update

Co-authored-by: kstvr32 <kstvr32@gmail.com>
Co-authored-by: Martin Robertz <dream-master@gmx.net>

dependencies.gradle

@@ -1,8 +1,8 @@
 // Add your dependencies here
 
 dependencies {
-    api("com.github.GTNewHorizons:GTNHLib:0.0.13:dev")
-    runtimeOnly("com.github.GTNewHorizons:NotEnoughItems:2.5.3-GTNH:dev")
+    api("com.github.GTNewHorizons:GTNHLib:0.5.22:dev")
+    runtimeOnly("com.github.GTNewHorizons:NotEnoughItems:2.6.51-GTNH:dev")
 
     testImplementation(platform('org.junit:junit-bom:5.9.2'))
     testImplementation('org.junit.jupiter:junit-jupiter')

gradle.properties

@@ -33,7 +33,7 @@ channel = stable
 mappingsVersion = 12
 
 # Defines other MCP mappings for dependency deobfuscation.
-remoteMappings = https://raw.githubusercontent.com/MinecraftForge/FML/1.7.10/conf/
+remoteMappings = https\://raw.githubusercontent.com/MinecraftForge/FML/1.7.10/conf/
 
 # Select a default username for testing your mod. You can always override this per-run by running
 # `./gradlew runClient --username=AnotherPlayer`, or configuring this command in your IDE.
@@ -41,19 +41,19 @@ developmentEnvironmentUserName = "Developer"
 
 # Enables using modern Java syntax (up to version 17) via Jabel, while still targeting JVM 8.
 # See https://github.com/bsideup/jabel for details on how this works.
-enableModernJavaSyntax = false
+enableModernJavaSyntax = true
 
 # Enables injecting missing generics into the decompiled source code for a better coding experience.
 # Turns most publicly visible List, Map, etc. into proper List<E>, Map<K, V> types.
-enableGenericInjection = false
+enableGenericInjection = true
 
 # Generate a class with a String field for the mod version named as defined below.
 # If generateGradleTokenClass is empty or not missing, no such class will be generated.
 # If gradleTokenVersion is empty or missing, the field will not be present in the class.
-generateGradleTokenClass =
+generateGradleTokenClass = com.gtnewhorizon.structurelib.Tags
 
 # Name of the token containing the project's current version to generate/replace.
-gradleTokenVersion = GRADLETOKEN_VERSION
+gradleTokenVersion = VERSION
 
 # [DEPRECATED] Mod ID replacement token.
 gradleTokenModId =
@@ -61,13 +61,16 @@ gradleTokenModId =
 # [DEPRECATED] Mod name replacement token.
 gradleTokenModName =
 
+# [DEPRECATED] Mod Group replacement token.
+gradleTokenGroupName =
+
 # [DEPRECATED]
 # Multiple source files can be defined here by providing a comma-separated list: Class1.java,Class2.java,Class3.java
 # public static final String VERSION = "GRADLETOKEN_VERSION";
 # The string's content will be replaced with your mod's version when compiled. You should use this to specify your mod's
 # version in @Mod([...], version = VERSION, [...]).
 # Leave these properties empty to skip individual token replacements.
-replaceGradleTokenInFile = StructureLib.java
+replaceGradleTokenInFile =
 
 # In case your mod provides an API for other mods to implement you may declare its package here. Otherwise, you can
 # leave this property empty.
@@ -80,7 +83,12 @@ apiPackage =
 accessTransformersFile =
 
 # Provides setup for Mixins if enabled. If you don't know what mixins are: Keep it disabled!
-usesMixins = false
+usesMixins = true
+
+# Set to a non-empty string to configure mixins in a separate source set under src/VALUE, instead of src/main.
+# This can speed up compile times thanks to not running the mixin annotation processor on all input sources.
+# Mixin classes will have access to "main" classes, but not the other way around.
+separateMixinSourceSet =
 
 # Adds some debug arguments like verbose output and class export.
 usesMixinDebug = false
@@ -89,12 +97,12 @@ usesMixinDebug = false
 mixinPlugin =
 
 # Specify the package that contains all of your Mixins. You may only place Mixins in this package or the build will fail!
-mixinsPackage =
+mixinsPackage = mixins
 
 # Specify the core mod entry class if you use a core mod. This class must implement IFMLLoadingPlugin!
 # This parameter is for legacy compatibility only
 # Example value: (coreModClass = asm.FMLPlugin) + (modGroup = com.myname.mymodid) -> com.myname.mymodid.asm.FMLPlugin
-coreModClass =
+coreModClass = core.StructureLibCore
 
 # If your project is only a consolidation of mixins or a core mod and does NOT contain a 'normal' mod ( = some class
 # that is annotated with @Mod) you want this to be true. When in doubt: leave it on false!
@@ -114,16 +122,22 @@ minimizeShadowedDependencies = true
 # If disabled, won't rename the shadowed classes.
 relocateShadowedDependencies = true
 
-# Adds the GTNH maven, CurseMaven, IC2/Player maven, and some more well-known 1.7.10 repositories.
+# Adds CurseMaven, Modrinth, and some more well-known 1.7.10 repositories.
 includeWellKnownRepositories = true
 
+# A list of repositories to exclude from the includeWellKnownRepositories setting. Should be a space separated
+# list of strings, with the acceptable keys being(case does not matter):
+# cursemaven
+# modrinth
+excludeWellKnownRepositories =
+
 # Change these to your Maven coordinates if you want to publish to a custom Maven repository instead of the default GTNH Maven.
 # Authenticate with the MAVEN_USER and MAVEN_PASSWORD environment variables.
 # If you need a more complex setup disable maven publishing here and add a publishing repository to addon.gradle.
 usesMavenPublishing = true
 
 # Maven repository to publish the mod to.
-# mavenPublishUrl = https://nexus.gtnewhorizons.com/repository/releases/
+# mavenPublishUrl = https\://nexus.gtnewhorizons.com/repository/releases/
 
 # Publishing to Modrinth requires you to set the MODRINTH_TOKEN environment variable to your current Modrinth API token.
 #
@@ -173,7 +187,7 @@ curseForgeRelations =
 # disableSpotless = true
 
 # Uncomment this to disable Checkstyle checks (currently wildcard import check).
-disableCheckstyle = true
+# disableCheckstyle = true
 
 # Override the IDEA build type. Valid values are: "" (leave blank, do not override), "idea" (force use native IDEA build), "gradle"
 # (force use delegated build).
@@ -187,5 +201,3 @@ disableCheckstyle = true
 # This is meant to be set in $HOME/.gradle/gradle.properties.
 # ideaCheckSpotlessOnBuild = true
 
-# Non-GTNH properties
-gradleTokenGroupName = 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

gradlew

@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -84,7 +86,8 @@ done
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
 # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum

gradlew.bat

@@ -13,6 +13,8 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################

settings.gradle

@@ -17,7 +17,7 @@ pluginManagement {
 }
 
 plugins {
-    id 'com.gtnewhorizons.gtnhsettingsconvention' version '1.0.8'
+    id 'com.gtnewhorizons.gtnhsettingsconvention' version '1.0.30'
 }
 
 

src/main/java/com/gtnewhorizon/structurelib/ClientProxy.java

@@ -2,15 +2,24 @@ package com.gtnewhorizon.structurelib;
 
 import static com.gtnewhorizon.structurelib.StructureLib.RANDOM;
 
-import java.util.*;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
 
 import net.minecraft.block.Block;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.entity.EntityClientPlayerMP;
 import net.minecraft.client.gui.GuiNewChat;
 import net.minecraft.client.particle.EntityFX;
 import net.minecraft.client.renderer.Tessellator;
 import net.minecraft.client.renderer.culling.Frustrum;
 import net.minecraft.client.renderer.texture.TextureMap;
+import net.minecraft.client.resources.I18n;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
@@ -23,18 +32,27 @@ import net.minecraft.util.Vec3;
 import net.minecraft.world.World;
 import net.minecraftforge.client.event.RenderWorldLastEvent;
 import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.common.config.ConfigElement;
+import net.minecraftforge.event.entity.EntityJoinWorldEvent;
 import net.minecraftforge.event.world.WorldEvent;
 
+import org.apache.commons.lang3.tuple.Pair;
 import org.lwjgl.opengl.GL11;
 
 import com.gtnewhorizon.structurelib.entity.fx.WeightlessParticleFX;
+import com.gtnewhorizon.structurelib.net.RegistryOrderSyncMessage;
 import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
 
+import cpw.mods.fml.client.config.GuiConfig;
+import cpw.mods.fml.client.event.ConfigChangedEvent;
 import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.event.FMLLoadCompleteEvent;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+import cpw.mods.fml.common.eventhandler.EventPriority;
 import cpw.mods.fml.common.eventhandler.SubscribeEvent;
 import cpw.mods.fml.common.gameevent.TickEvent.ClientTickEvent;
 import cpw.mods.fml.common.gameevent.TickEvent.Phase;
+import cpw.mods.fml.common.network.FMLNetworkEvent;
 
 public class ClientProxy extends CommonProxy {
 
@@ -246,6 +264,47 @@ public class ClientProxy extends CommonProxy {
             ((IStructureCompat) StructureLib.COMPAT).markTextureUsed(icon);
     }
 
+    static void sendRegistryOrderToServer() {
+        if (FMLEventHandler.configSent) return;
+        FMLEventHandler.configSent = true;
+        for (String s : SortedRegistry.ALL_REGISTRIES.keySet()) {
+            Pair<List<String>, List<String>> registryOrder = ConfigurationHandler.INSTANCE.getRegistryOrder(s);
+            if (registryOrder == null || registryOrder.getKey().isEmpty() && registryOrder.getValue().isEmpty())
+                continue;
+            StructureLib.net
+                    .sendToServer(new RegistryOrderSyncMessage(s, registryOrder.getKey(), registryOrder.getValue()));
+        }
+    }
+
+    @Override
+    public void loadComplete(FMLLoadCompleteEvent evt) {
+        super.loadComplete(evt);
+        for (Map.Entry<String, WeakReference<SortedRegistry<?>>> e : SortedRegistry.ALL_REGISTRIES.entrySet()) {
+            SortedRegistry<?> r = e.getValue().get();
+            if (r == null) continue;
+            Pair<List<String>, List<String>> p = ConfigurationHandler.INSTANCE.getRegistryOrder(e.getKey());
+            r.registerOrdering(getSPPlayerUUID(), p.getKey(), p.getValue());
+        }
+    }
+
+    public UUID getSPPlayerUUID() {
+        return EntityPlayer.func_146094_a(Minecraft.getMinecraft().getSession().func_148256_e());
+    }
+
+    public void displayConfigGUI(String category) {
+        ConfigElement<Object> element = new ConfigElement<>(
+                ConfigurationHandler.INSTANCE.getConfig().getCategory(category));
+        GuiConfig guiConfig = new GuiConfig(
+                null,
+                element.getChildElements(),
+                StructureLibAPI.MOD_ID,
+                null,
+                false,
+                false,
+                I18n.format(element.getLanguageKey()));
+        Minecraft.getMinecraft().displayGuiScreen(guiConfig);
+    }
+
     private static class HintGroup {
 
         private final List<HintParticleInfo> hints = new LinkedList<>();
@@ -434,12 +493,34 @@ public class ClientProxy extends CommonProxy {
 
     public static class FMLEventHandler {
 
+        static boolean connected = false;
+        static boolean configSent = false;
+
         private void resetPlayerLocation() {
             lastPlayerPos.xCoord = Minecraft.getMinecraft().thePlayer.posX;
             lastPlayerPos.yCoord = Minecraft.getMinecraft().thePlayer.posY;
             lastPlayerPos.zCoord = Minecraft.getMinecraft().thePlayer.posZ;
         }
 
+        @SubscribeEvent
+        public void onPlayerLogIn(FMLNetworkEvent.ClientConnectedToServerEvent e) {
+            connected = true;
+            configSent = false;
+        }
+
+        @SubscribeEvent
+        public void onPlayerLogOut(FMLNetworkEvent.ClientDisconnectionFromServerEvent e) {
+            connected = false;
+        }
+
+        @SubscribeEvent(priority = EventPriority.LOWEST)
+        public void onConfigChange(ConfigChangedEvent.PostConfigChangedEvent e) {
+            if (connected && e.modID.equals(StructureLibAPI.MOD_ID)) {
+                configSent = false;
+                sendRegistryOrderToServer();
+            }
+        }
+
         @SubscribeEvent
         public void onClientTick(ClientTickEvent e) {
             if (e.phase == Phase.END && Minecraft.getMinecraft().thePlayer != null) {
@@ -483,6 +564,13 @@ public class ClientProxy extends CommonProxy {
 
     public static class ForgeEventHandler {
 
+        @SubscribeEvent
+        public void onEntityJoinWorld(EntityJoinWorldEvent e) {
+            if (e.world.isRemote && e.entity instanceof EntityClientPlayerMP) {
+                sendRegistryOrderToServer();
+            }
+        }
+
         @SubscribeEvent
         public void onWorldLoad(WorldEvent.Load e) {
             if (e.world.isRemote) {

src/main/java/com/gtnewhorizon/structurelib/CommonProxy.java

@@ -12,14 +12,23 @@ import net.minecraft.server.MinecraftServer;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
+import net.minecraftforge.common.MinecraftForge;
 
 import com.gtnewhorizon.structurelib.net.ErrorHintParticleMessage;
 import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
 
+import cpw.mods.fml.common.event.FMLLoadCompleteEvent;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+import cpw.mods.fml.common.gameevent.TickEvent;
 
 public class CommonProxy {
 
+    public CommonProxy() {
+        super();
+        MinecraftForge.EVENT_BUS.register(new ForgeEventHandler());
+    }
+
     public void hintParticleTinted(World w, int x, int y, int z, IIcon[] icons, short[] RGBa) {}
 
     public void hintParticleTinted(World w, int x, int y, int z, Block block, int meta, short[] RGBa) {}
@@ -70,6 +79,10 @@ public class CommonProxy {
         }
     }
 
+    public void loadComplete(FMLLoadCompleteEvent e) {
+        ConfigurationHandler.INSTANCE.loadRegistryOrder();
+    }
+
     private final Map<EntityPlayerMP, Map<Object, Long>> throttleMap = new WeakHashMap<>();
 
     public void addThrottledChat(Object throttleKey, EntityPlayer player, IChatComponent text, short intervalRequired,
@@ -94,4 +107,22 @@ public class CommonProxy {
             if (!forceUpdateLastSend) submap.put(throttleKey, now);
         }
     }
+
+    public void displayConfigGUI(String category) {}
+
+    public static class ForgeEventHandler {
+
+        private int ticksSinceLastPurge;
+
+        @SubscribeEvent
+        public void onServerTickEnd(TickEvent.ServerTickEvent e) {
+            if (e.phase != TickEvent.Phase.END) return;
+            if (++ticksSinceLastPurge < 20 * 60 * 10) return;
+            ticksSinceLastPurge = 0;
+            MinecraftServer server = MinecraftServer.getServer();
+            // it's hard to tell why server could be null in a server tick handler, but who knows?
+            if (server == null) return;
+            SortedRegistry.cleanup(server);
+        }
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/ConfigurationHandler.java

@@ -1,15 +1,26 @@
 package com.gtnewhorizon.structurelib;
 
 import java.io.File;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import net.minecraftforge.common.config.ConfigCategory;
 import net.minecraftforge.common.config.Configuration;
 import net.minecraftforge.common.config.Property;
 
+import org.apache.commons.lang3.tuple.Pair;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+
 import cpw.mods.fml.client.event.ConfigChangedEvent;
 import cpw.mods.fml.common.FMLCommonHandler;
 import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+import cpw.mods.fml.relauncher.FMLLaunchHandler;
 
 public enum ConfigurationHandler {
 
@@ -22,6 +33,7 @@ public enum ConfigurationHandler {
     private int hintTransparency;
     private int autoPlaceBudget;
     private int autoPlaceInterval;
+    private Map<String, Pair<List<String>, List<String>>> registryOrders;
 
     ConfigurationHandler() {
         FMLCommonHandler.instance().bus().register(this);
@@ -86,8 +98,50 @@ public enum ConfigurationHandler {
                         + "Note this relates to the wall clock, not in game ticks.\n"
                         + "Value smaller than default is likely to be perceived as no minimal interval whatsoever.");
 
+        loadRegistryOrder();
+
+        saveConfig();
+    }
+
+    void loadRegistryOrder() {
+        loadRegistryOrderImpl();
+        setLanguageKeys();
+        saveConfig();
+    }
+
+    private void loadRegistryOrderImpl() {
+        registryOrders = new HashMap<>();
+        for (Map.Entry<String, WeakReference<SortedRegistry<?>>> e : SortedRegistry.ALL_REGISTRIES.entrySet()) {
+            SortedRegistry<?> r = e.getValue().get();
+            if (r == null) continue;
+            String category = "registries." + e.getKey();
+            if (FMLLaunchHandler.side().isClient()) {
+                // only meaningful on client, and would crash on server
+                config.setCategoryConfigEntryClass(category, RegistryOrderEntry.class);
+            }
+            Property pOrder = config.get(
+                    category,
+                    "ordering",
+                    Iterables.toArray(r.getCurrentOrdering(), String.class),
+                    "stuff not in this list will be automatically available after all entries listed here in their natural order, unless explicitly disabled in disabled config below.");
+            Property pDisable = config.get(category, "disabled", new String[0], "stuff in this list will be disabled");
+            List<String> all = Lists.newArrayList(r.getCurrentOrdering());
+            List<String> curVal = new ArrayList<>(Arrays.asList(pOrder.getStringList()));
+            List<String> disabled = new ArrayList<>(Arrays.asList(pDisable.getStringList()));
+            curVal.removeAll(disabled);
+            all.removeAll(disabled);
+            curVal.removeIf(s -> !all.remove(s));
+            curVal.addAll(all);
+            pOrder.set(curVal.toArray(new String[0]));
+            registryOrders.put(e.getKey(), Pair.of(curVal, disabled));
+        }
+        saveConfig();
+    }
+
+    private void saveConfig() {
         if (config.hasChanged()) {
             config.save();
+            config.load();
         }
     }
 
@@ -122,7 +176,12 @@ public enum ConfigurationHandler {
         return autoPlaceInterval;
     }
 
+    public Pair<List<String>, List<String>> getRegistryOrder(String name) {
+        return registryOrders.get(name);
+    }
+
     Configuration getConfig() {
         return config;
     }
+
 }

src/main/java/com/gtnewhorizon/structurelib/GuiEditRegistryConfig.java

@@ -0,0 +1,702 @@
+/*
+ * Forge Mod Loader Copyright (c) 2012-2014 cpw. All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the GNU Lesser Public License v2.1 which accompanies this distribution, and is
+ * available at http://www.gnu.org/licenses/old-licenses/gpl-2.0.html Contributors (this class): bspkrs - implementation
+ */
+
+package com.gtnewhorizon.structurelib;
+
+import static cpw.mods.fml.client.config.GuiUtils.RESET_CHAR;
+import static cpw.mods.fml.client.config.GuiUtils.UNDO_CHAR;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.WeakHashMap;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.FontRenderer;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiListExtended;
+import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.gui.ScaledResolution;
+import net.minecraft.client.renderer.OpenGlHelper;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.resources.I18n;
+import net.minecraft.util.EnumChatFormatting;
+import net.minecraft.util.MathHelper;
+import net.minecraft.util.ResourceLocation;
+
+import org.lwjgl.input.Keyboard;
+import org.lwjgl.opengl.GL11;
+
+import cpw.mods.fml.client.config.GuiButtonExt;
+import cpw.mods.fml.client.config.GuiConfig;
+import cpw.mods.fml.client.config.GuiUnicodeGlyphButton;
+import cpw.mods.fml.client.config.GuiUtils;
+import cpw.mods.fml.client.config.HoverChecker;
+import cpw.mods.fml.client.config.IConfigElement;
+import cpw.mods.fml.client.event.ConfigChangedEvent;
+import cpw.mods.fml.client.event.ConfigChangedEvent.OnConfigChangedEvent;
+import cpw.mods.fml.client.event.ConfigChangedEvent.PostConfigChangedEvent;
+import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.Loader;
+import cpw.mods.fml.common.eventhandler.Event.Result;
+
+/**
+ * This class is the base GuiScreen for all config GUI screens. It can be extended by mods to provide the top-level
+ * config screen that will be called when the Config button is clicked from the Main Menu Mods list.
+ *
+ * @author bspkrs
+ */
+public class GuiEditRegistryConfig extends GuiScreen {
+
+    public static final String OMITTED = "..";
+    public static final int LIST_WINDOW_PADDING = 20;
+    public static final int MID_SECTION_WIDTH = 10;
+    /**
+     * A reference to the screen object that created this. Used for navigating between screens.
+     */
+    public final GuiScreen parentScreen;
+    private final IConfigElement<String> disabledElement;
+    private final String[] beforeDisabledValue;
+    private final IConfigElement<String> orderElement;
+    private final String[] beforeOrderValue;
+    final Collection<EntriesList> lists;
+    private final String registryName;
+    EntriesList disabledEntries;
+    EntriesList orderEntries;
+    public String title = "Config GUI";
+    public String titleLine2;
+    private GuiButtonExt btnDefault;
+    private GuiButtonExt btnUndoAll;
+    public final String modID;
+    /**
+     * When set to a non-null value the OnConfigChanged and PostConfigChanged events will be posted when the Done button
+     * is pressed if any configElements were changed (includes child screens). If not defined, the events will be posted
+     * if the parent gui is null or if the parent gui is not an instance of GuiConfig.
+     */
+    public final String configID;
+    public final boolean isWorldRunning;
+    public final boolean allRequireWorldRestart;
+    public final boolean allRequireMcRestart;
+    public boolean needsRefresh = true;
+    private HoverChecker undoHoverChecker;
+    private HoverChecker resetHoverChecker;
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public GuiEditRegistryConfig(GuiScreen parentScreen, IConfigElement disabled, IConfigElement order,
+            String registryName, String modID, String configID, boolean allRequireWorldRestart,
+            boolean allRequireMcRestart, String title, String titleLine2) {
+        this.mc = parentScreen.mc;
+        this.lists = Collections.newSetFromMap(new WeakHashMap<>());
+        this.disabledElement = disabled;
+        this.beforeDisabledValue = (String[]) this.disabledElement.getList();
+        this.orderElement = order;
+        this.beforeOrderValue = (String[]) this.orderElement.getList();
+        this.parentScreen = parentScreen;
+        this.allRequireWorldRestart = allRequireWorldRestart;
+        this.allRequireMcRestart = allRequireMcRestart;
+        this.registryName = registryName;
+        this.modID = modID;
+        this.configID = configID;
+        this.isWorldRunning = mc.theWorld != null;
+        if (title != null) this.title = title;
+        this.titleLine2 = titleLine2;
+        if (this.titleLine2 != null && this.titleLine2.startsWith(" > "))
+            this.titleLine2 = this.titleLine2.replaceFirst(" > ", "");
+    }
+
+    /**
+     * Adds the buttons (and other controls) to the screen in question.
+     */
+    @SuppressWarnings("unchecked")
+    @Override
+    public void initGui() {
+        Keyboard.enableRepeatEvents(true);
+        if (this.disabledEntries == null || this.needsRefresh) {
+            this.disabledEntries = new EntriesList(
+                    (width - MID_SECTION_WIDTH) / 2 - LIST_WINDOW_PADDING,
+                    LIST_WINDOW_PADDING,
+                    I18n.format("structurelib.configgui.disabled"));
+            this.disabledEntries.initEntries(Arrays.asList(disabledElement.getList()));
+        } else {
+            this.disabledEntries.reinit((width - MID_SECTION_WIDTH) / 2 - LIST_WINDOW_PADDING, LIST_WINDOW_PADDING);
+        }
+        if (this.orderEntries == null || this.needsRefresh) {
+            this.orderEntries = new EntriesList(
+                    (width - MID_SECTION_WIDTH) / 2 - LIST_WINDOW_PADDING,
+                    (width + MID_SECTION_WIDTH) / 2,
+                    I18n.format("structurelib.configgui.enabled"));
+            this.orderEntries.initEntries(Arrays.asList(orderElement.getList()));
+        } else {
+            this.orderEntries
+                    .reinit((width - MID_SECTION_WIDTH) / 2 - LIST_WINDOW_PADDING, (width + MID_SECTION_WIDTH) / 2);
+        }
+        this.needsRefresh = false;
+
+        int undoGlyphWidth = mc.fontRenderer.getStringWidth(UNDO_CHAR) * 2;
+        int resetGlyphWidth = mc.fontRenderer.getStringWidth(RESET_CHAR) * 2;
+        int doneWidth = Math.max(mc.fontRenderer.getStringWidth(I18n.format("gui.done")) + 20, 100);
+        int undoWidth = mc.fontRenderer.getStringWidth(" " + I18n.format("fml.configgui.tooltip.undoChanges"))
+                + undoGlyphWidth
+                + 20;
+        int resetWidth = mc.fontRenderer.getStringWidth(" " + I18n.format("fml.configgui.tooltip.resetToDefault"))
+                + resetGlyphWidth
+                + 20;
+        int buttonWidthHalf = (doneWidth + 5 + undoWidth + 5 + resetWidth + 5) / 2;
+        this.buttonList.add(
+                new GuiButtonExt(
+                        2000,
+                        this.width / 2 - buttonWidthHalf,
+                        this.height - 29,
+                        doneWidth,
+                        20,
+                        I18n.format("gui.done")));
+        this.buttonList.add(
+                this.btnDefault = new GuiUnicodeGlyphButton(
+                        2001,
+                        this.width / 2 - buttonWidthHalf + doneWidth + 5 + undoWidth + 5,
+                        this.height - 29,
+                        resetWidth,
+                        20,
+                        " " + I18n.format("fml.configgui.tooltip.resetToDefault"),
+                        RESET_CHAR,
+                        2.0F));
+        this.buttonList.add(
+                btnUndoAll = new GuiUnicodeGlyphButton(
+                        2002,
+                        this.width / 2 - buttonWidthHalf + doneWidth + 5,
+                        this.height - 29,
+                        undoWidth,
+                        20,
+                        " " + I18n.format("fml.configgui.tooltip.undoChanges"),
+                        UNDO_CHAR,
+                        2.0F));
+
+        this.undoHoverChecker = new HoverChecker(this.btnUndoAll, 800);
+        this.resetHoverChecker = new HoverChecker(this.btnDefault, 800);
+    }
+
+    /**
+     * Called when the screen is unloaded. Used to disable keyboard repeat events
+     */
+    @Override
+    public void onGuiClosed() {
+        if (this.configID != null && this.parentScreen instanceof GuiConfig) {
+            GuiConfig parentGuiConfig = (GuiConfig) this.parentScreen;
+            parentGuiConfig.needsRefresh = true;
+            parentGuiConfig.initGui();
+        }
+
+        if (!(this.parentScreen instanceof GuiConfig)) Keyboard.enableRepeatEvents(false);
+    }
+
+    public boolean saveConfigElements() {
+        if (isChanged()) {
+            disabledElement.set(disabledEntries.entries.stream().map(e -> e.name).toArray(String[]::new));
+            orderElement.set(orderEntries.entries.stream().map(e -> e.name).toArray(String[]::new));
+        }
+        return false;
+    }
+
+    @Override
+    protected void actionPerformed(GuiButton button) {
+        if (button.id == 2000) {
+            try {
+                if ((configID != null || this.parentScreen == null || !(this.parentScreen instanceof GuiConfig))
+                        && isChanged()) {
+                    saveConfigElements();
+                    if (Loader.isModLoaded(modID)) {
+                        ConfigChangedEvent event = new OnConfigChangedEvent(modID, configID, isWorldRunning, false);
+                        FMLCommonHandler.instance().bus().post(event);
+                        if (!event.getResult().equals(Result.DENY)) FMLCommonHandler.instance().bus()
+                                .post(new PostConfigChangedEvent(modID, configID, isWorldRunning, false));
+
+                        if (this.parentScreen instanceof GuiConfig) ((GuiConfig) this.parentScreen).needsRefresh = true;
+                    }
+                }
+            } catch (Throwable e) {
+                e.printStackTrace();
+            }
+
+            this.mc.displayGuiScreen(this.parentScreen);
+        } else if (button.id == 2001) {
+            setToDefault();
+        } else if (button.id == 2002) {
+            undoChanges();
+        }
+    }
+
+    public boolean isInitialized() {
+        return disabledEntries != null && orderEntries != null;
+    }
+
+    public void undoChanges() {
+        disabledEntries.initEntries(Arrays.asList(beforeDisabledValue));
+        orderEntries.initEntries(Arrays.asList(beforeOrderValue));
+    }
+
+    public void setToDefault() {
+        disabledEntries.initEntries(Arrays.asList(disabledElement.getList()));
+        orderEntries.initEntries(Arrays.asList(orderElement.getList()));
+    }
+
+    public boolean isDefault() {
+        return !orderEntries.areContentEqual(orderElement.getDefaults())
+                || !disabledEntries.areContentEqual(disabledElement.getDefaults());
+    }
+
+    public boolean isChanged() {
+        return !orderEntries.areContentEqual(beforeOrderValue) || !disabledEntries.areContentEqual(beforeDisabledValue);
+    }
+
+    /**
+     * Called when the mouse is clicked.
+     */
+    @Override
+    protected void mouseClicked(int x, int y, int mouseEvent) {
+        if (mouseEvent != 0 || !this.disabledEntries.func_148179_a(x, y, mouseEvent)
+                && !this.orderEntries.func_148179_a(x, y, mouseEvent)) {
+            super.mouseClicked(x, y, mouseEvent);
+        }
+    }
+
+    /**
+     * Called when the mouse is moved or a mouse button is released. Signature: (mouseX, mouseY, which) which==-1 is
+     * mouseMove, which==0 or which==1 is mouseUp
+     */
+    @Override
+    protected void mouseMovedOrUp(int x, int y, int mouseEvent) {
+        if (mouseEvent != 0 || !this.disabledEntries.func_148181_b(x, y, mouseEvent)
+                && !this.orderEntries.func_148181_b(x, y, mouseEvent)) {
+            super.mouseMovedOrUp(x, y, mouseEvent);
+        }
+    }
+
+    /**
+     * Fired when a key is typed. This is the equivalent of KeyListener.keyTyped(KeyEvent e).
+     */
+    @Override
+    protected void keyTyped(char eventChar, int eventKey) {
+        if (eventKey == Keyboard.KEY_ESCAPE) this.mc.displayGuiScreen(parentScreen);
+    }
+
+    String trimStringToWidth(String str, int width) {
+        int strwidth = mc.fontRenderer.getStringWidth(str);
+        int elipsisWidth = mc.fontRenderer.getStringWidth(OMITTED);
+        if (strwidth > width - elipsisWidth && elipsisWidth > strwidth) {
+            return mc.fontRenderer.trimStringToWidth(str, width - elipsisWidth).trim() + OMITTED;
+        }
+        return str;
+    }
+
+    /**
+     * Draws the screen and all the components in it.
+     */
+    @Override
+    public void drawScreen(int mouseX, int mouseY, float partialTicks) {
+        for (EntriesList list : lists) {
+            list.handleDrag(mouseX, mouseY, partialTicks);
+        }
+        this.drawDefaultBackground();
+        for (EntriesList list : lists) {
+            list.drawScreen(mouseX, mouseY, partialTicks);
+        }
+        this.drawCenteredString(this.fontRendererObj, this.title, this.width / 2, 8, 16777215);
+        String title2 = this.titleLine2;
+
+        if (title2 != null) {
+            title2 = trimStringToWidth(title2, width - 6);
+            this.drawCenteredString(this.fontRendererObj, title2, this.width / 2, 18, 16777215);
+        }
+
+        this.btnUndoAll.enabled = isChanged();
+        this.btnDefault.enabled = isDefault();
+        super.drawScreen(mouseX, mouseY, partialTicks);
+        for (EntriesList list : lists) {
+            list.drawScreenPost(mouseX, mouseY, partialTicks);
+        }
+        if (this.undoHoverChecker.checkHover(mouseX, mouseY)) this.drawToolTip(
+                this.mc.fontRenderer.listFormattedStringToWidth(I18n.format("fml.configgui.tooltip.undoAll"), 300),
+                mouseX,
+                mouseY);
+        if (this.resetHoverChecker.checkHover(mouseX, mouseY)) this.drawToolTip(
+                this.mc.fontRenderer.listFormattedStringToWidth(I18n.format("fml.configgui.tooltip.resetAll"), 300),
+                mouseX,
+                mouseY);
+    }
+
+    @SuppressWarnings("rawtypes")
+    public void drawToolTip(List stringList, int x, int y) {
+        this.func_146283_a(stringList, x, y);
+    }
+
+    private class EntriesList extends GuiListExtended {
+
+        final String heading;
+        final List<ListEntry> entries = new ArrayList<>();
+        int controlX;
+
+        public EntriesList(int width, int left, String heading) {
+            super(
+                    mc,
+                    width,
+                    GuiEditRegistryConfig.this.height,
+                    titleLine2 != null ? 33 : 23,
+                    GuiEditRegistryConfig.this.height - 32,
+                    20);
+            this.heading = heading;
+            if (heading != null) {
+                setHasListHeader(true, mc.fontRenderer.FONT_HEIGHT + 4);
+            }
+            setSlotXBoundsFromLeft(left);
+            this.controlX = this.getScrollBarX() - 20;
+            lists.add(this);
+        }
+
+        @Override
+        public void drawScreen(int p_148128_1_, int p_148128_2_, float p_148128_3_) {
+            GL11.glEnable(GL11.GL_SCISSOR_TEST);
+            ScaledResolution scaledresolution = new ScaledResolution(mc, mc.displayWidth, mc.displayHeight);
+            GL11.glScissor(
+                    (left - 4) * scaledresolution.getScaleFactor(),
+                    (int) ((scaledresolution.getScaledHeight_double() - (bottom + 4))
+                            * scaledresolution.getScaleFactor()),
+                    (width + 8) * scaledresolution.getScaleFactor(),
+                    (height + 8) * scaledresolution.getScaleFactor());
+            super.drawScreen(p_148128_1_, p_148128_2_, p_148128_3_);
+            GL11.glDisable(GL11.GL_SCISSOR_TEST);
+        }
+
+        @Override
+        public void overlayBackground(int p_148136_1_, int p_148136_2_, int p_148136_3_, int p_148136_4_) {}
+
+        @Override
+        protected void drawContainerBackground(Tessellator tessellator) {
+            GL11.glEnable(GL11.GL_BLEND);
+            OpenGlHelper.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, 0, 1);
+            GL11.glDisable(GL11.GL_ALPHA_TEST);
+            GL11.glShadeModel(GL11.GL_SMOOTH);
+            GL11.glDisable(GL11.GL_TEXTURE_2D);
+            tessellator.startDrawingQuads();
+            tessellator.setColorRGBA_I(0, 64);
+            tessellator.addVertex(left, bottom, 0);
+            tessellator.addVertex(right, bottom, 0);
+            tessellator.addVertex(right, top, 0);
+            tessellator.addVertex(left, top, 0);
+            tessellator.draw();
+            GL11.glEnable(GL11.GL_TEXTURE_2D);
+            GL11.glShadeModel(GL11.GL_FLAT);
+            GL11.glEnable(GL11.GL_ALPHA_TEST);
+            GL11.glDisable(GL11.GL_BLEND);
+        }
+
+        @Override
+        protected void drawListHeader(int p_148129_1_, int p_148129_2_, Tessellator p_148129_3_) {
+            if (heading == null) {
+                return;
+            }
+            FontRenderer fr = mc.fontRenderer;
+            fr.drawString(
+                    this.heading,
+                    p_148129_1_ + this.width / 2 - fr.getStringWidth(this.heading) / 2,
+                    Math.min(this.top + 3, p_148129_2_),
+                    0xffffff);
+        }
+
+        void reinit(int width, int left) {
+            this.width = width;
+            this.bottom = GuiEditRegistryConfig.this.height - 32;
+            this.setSlotXBoundsFromLeft(left);
+            this.controlX = this.getScrollBarX() - 20;
+        }
+
+        void initEntries(Iterable<?> entries) {
+            this.controlX = this.getScrollBarX() - 20;
+            this.entries.clear();
+            for (Object entry : entries) {
+                addEntry(new ListEntry(entry.toString()));
+            }
+        }
+
+        void addEntry(ListEntry entry) {
+            entry.entriesList = this;
+            this.entries.add(entry);
+            this.controlX = Math.min(this.controlX, this.getScrollBarX() - entry.getControlSetWidth() - 2);
+        }
+
+        @Override
+        public IGuiListEntry getListEntry(int i) {
+            return entries.get(i);
+        }
+
+        @Override
+        protected int getSize() {
+            return entries.size();
+        }
+
+        int getLabelX() {
+            return left + 2;
+        }
+
+        int getControlX() {
+            return controlX;
+        }
+
+        @Override
+        public int getListWidth() {
+            return width;
+        }
+
+        @Override
+        protected int getScrollBarX() {
+            return left + getListWidth() - 6;
+        }
+
+        public void handleDrag(int mouseX, int mouseY, float partialTicks) {
+            for (int i = 0, entriesSize = entries.size(); i < entriesSize; i++) {
+                ListEntry entry = entries.get(i);
+                if (entry.handleDrag(i, mouseX, mouseY, partialTicks)) {
+                    return;
+                }
+            }
+        }
+
+        public void drawScreenPost(int mouseX, int mouseY, float partialTicks) {
+            for (ListEntry entry : entries) {
+                entry.drawToolTip(mouseX, mouseY);
+            }
+        }
+
+        public boolean areContentEqual(Object[] vals) {
+            if (vals.length != entries.size()) return false;
+            for (int i = 0; i < entries.size(); i++) {
+                ListEntry entry = entries.get(i);
+                if (!entry.name.equals(vals[i])) return false;
+            }
+            return true;
+        }
+    }
+
+    class ListEntry implements GuiListExtended.IGuiListEntry {
+
+        private EntriesList entriesList;
+        private final HoverChecker hoverCheckerText = new HoverChecker(0, 0, 0, 0, 0);
+        final String name;
+        final String localizedName;
+        private final String tooltip;
+        public boolean modified = false;
+
+        private final GuiButtonExt btnDrag = new GuiButtonDrag(1, 0, 0, 20, 20);
+        private final HoverChecker hoverCheckerBtnDrag = new HoverChecker(btnDrag, 800);
+        private boolean isDragging = false;
+        private long lastScroll = 0;
+
+        ListEntry(String name) {
+            this.name = name;
+            String nameKey = "structurelib.sortedregistry." + registryName + "." + name;
+            this.localizedName = trans(nameKey, name);
+
+            String tooltipKey = nameKey + ".tooltip";
+            String tooltip = trans(tooltipKey, null);
+            StringBuilder tooltipBuilder = new StringBuilder();
+            tooltipBuilder.append(EnumChatFormatting.GREEN);
+            tooltipBuilder.append(this.localizedName);
+            if (tooltip != null) {
+                tooltipBuilder.append('\n').append(EnumChatFormatting.YELLOW).append(tooltip);
+            }
+            tooltipBuilder.append('\n');
+            tooltipBuilder.append(EnumChatFormatting.DARK_GRAY);
+            tooltipBuilder.append(this.name);
+            this.tooltip = tooltipBuilder.toString();
+        }
+
+        @Override
+        public void drawEntry(int slotIndex, int x, int y, int listWidth, int slotHeight, Tessellator tessellator,
+                int mouseX, int mouseY, boolean isSelected) {
+            drawOutlineBox(x, y, listWidth, slotHeight, tessellator);
+            drawLabel(y, slotHeight);
+            drawControlSet(y, slotHeight, mouseX, mouseY);
+        }
+
+        private void drawOutlineBox(int x, int y, int listWidth, int slotHeight, Tessellator tessellator) {
+            if (isDragging) {
+                // left x, right x, top y, bottom y
+                int lx = x, rx = entriesList.getScrollBarX() - 4, ty = y, by = y + slotHeight;
+                GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
+                GL11.glDisable(GL11.GL_TEXTURE_2D);
+                tessellator.startDrawingQuads();
+                tessellator.setColorOpaque_I(0x808080);
+                tessellator.addVertexWithUV(lx - 4, by + 4, 0.0D, 0.0D, 1.0D);
+                tessellator.addVertexWithUV(rx + 4, by + 4, 0.0D, 1.0D, 1.0D);
+                tessellator.addVertexWithUV(rx + 4, ty - 4, 0.0D, 1.0D, 0.0D);
+                tessellator.addVertexWithUV(lx - 4, ty - 4, 0.0D, 0.0D, 0.0D);
+                tessellator.setColorOpaque_I(0x202020);
+                tessellator.addVertexWithUV(lx - 2, by + 2, 0.0D, 0.0D, 1.0D);
+                tessellator.addVertexWithUV(rx + 2, by + 2, 0.0D, 1.0D, 1.0D);
+                tessellator.addVertexWithUV(rx + 2, ty - 2, 0.0D, 1.0D, 0.0D);
+                tessellator.addVertexWithUV(lx - 2, ty - 2, 0.0D, 0.0D, 0.0D);
+                tessellator.draw();
+                GL11.glEnable(GL11.GL_TEXTURE_2D);
+            }
+        }
+
+        private void drawControlSet(int y, int slotHeight, int mouseX, int mouseY) {
+            btnDrag.xPosition = entriesList.getControlX();
+            btnDrag.yPosition = y + (slotHeight - btnDrag.height) / 2;
+            btnDrag.drawButton(mc, mouseX, mouseY);
+        }
+
+        private void drawLabel(int y, int slotHeight) {
+            String label = modified ? EnumChatFormatting.ITALIC + localizedName : localizedName;
+            int allowedWidth = entriesList.getControlX() - entriesList.getLabelX() - 4;
+            // probably not very wise to recompute this every render tick, but it doesn't matter for now
+            String toDraw = trimStringToWidth(label, allowedWidth);
+            hoverCheckerText.updateBounds(
+                    y + slotHeight / 2 - mc.fontRenderer.FONT_HEIGHT / 2,
+                    y + slotHeight / 2 + mc.fontRenderer.FONT_HEIGHT / 2,
+                    entriesList.getLabelX(),
+                    entriesList.getLabelX() + mc.fontRenderer.getStringWidth(toDraw));
+
+            mc.fontRenderer.drawString(
+                    toDraw,
+                    entriesList.getLabelX(),
+                    y + slotHeight / 2 - mc.fontRenderer.FONT_HEIGHT / 2,
+                    getLabelColor());
+        }
+
+        void drawToolTip(int mouseX, int mouseY) {
+            // ensure checkHover() is always called, or the hover threshold might fail under certain corner cases
+            if (hoverCheckerText.checkHover(mouseX, mouseY)) {
+                GuiEditRegistryConfig.this.drawToolTip(
+                        mc.fontRenderer.listFormattedStringToWidth(tooltip, entriesList.getListWidth()),
+                        mouseX,
+                        mouseY);
+            }
+            if (hoverCheckerBtnDrag.checkHover(mouseX, mouseY) && !isDragging) {
+                GuiEditRegistryConfig.this.drawToolTip(
+                        mc.fontRenderer.listFormattedStringToWidth(
+                                I18n.format("structurelib.configgui.drag.tooltip"),
+                                entriesList.getListWidth()),
+                        mouseX,
+                        mouseY);
+            }
+        }
+
+        protected int getLabelColor() {
+            return isDragging ? 0x888888 : 0xffffff;
+        }
+
+        int getControlSetWidth() {
+            return this.btnDrag.getButtonWidth();
+        }
+
+        public boolean handleDrag(int index, int mouseX, int mouseY, float partialTicks) {
+            if (!isDragging) {
+                return false;
+            }
+            for (EntriesList list : lists) {
+                if (list == entriesList) continue;
+                if (mouseX > list.left && mouseX < list.right && mouseY > list.top && mouseY < list.bottom) {
+                    int l;
+                    if (list.entries.isEmpty()) l = 0;
+                    else l = list.func_148124_c(mouseX, mouseY);
+                    if (l < 0) {
+                        if (mouseY < (list.bottom + list.top) / 2) {
+                            l = 0;
+                        } else {
+                            l = list.entries.size();
+                        }
+                    }
+                    entriesList.func_148143_b(true);
+                    entriesList.entries.remove(index);
+                    list.func_148143_b(false);
+                    list.entries.add(l, this);
+                    this.entriesList = list;
+                    return true;
+                }
+            }
+            long now = System.currentTimeMillis();
+            if (now - lastScroll > 20) {
+                if (mouseY < entriesList.top) {
+                    entriesList.scrollBy(-3);
+                    lastScroll = now;
+                } else if (mouseY > entriesList.bottom) {
+                    entriesList.scrollBy(3);
+                    lastScroll = now;
+                }
+            }
+            int l = entriesList.func_148124_c(
+                    MathHelper.clamp_int(mouseX, entriesList.left, entriesList.right),
+                    MathHelper.clamp_int(mouseY, entriesList.top, entriesList.bottom));
+            if (l < 0 || l == index) return true;
+            entriesList.entries.remove(index);
+            entriesList.entries.add(l, this);
+            return true;
+        }
+
+        @Override
+        public void mouseReleased(int index, int x, int y, int mouseEvent, int relativeX, int relativeY) {
+            isDragging = false;
+        }
+
+        @Override
+        public boolean mousePressed(int index, int x, int y, int mouseEvent, int relativeX, int relativeY) {
+            if (btnDrag.mousePressed(mc, x, y)) {
+                isDragging = true;
+                return true;
+            }
+            return false;
+        }
+    }
+
+    private static String trans(String transKey, String fallback) {
+        String translated = I18n.format(transKey);
+        return translated.equals(transKey) ? fallback : translated;
+    }
+
+    private static class GuiButtonDrag extends GuiButtonExt {
+
+        public GuiButtonDrag(int id, int xPos, int yPos, int width, int height) {
+            super(id, xPos, yPos, width, height, null);
+        }
+
+        @Override
+        public void drawButton(Minecraft mc, int mouseX, int mouseY) {
+            if (this.visible) {
+                this.field_146123_n = mouseX >= this.xPosition && mouseY >= this.yPosition
+                        && mouseX < this.xPosition + this.width
+                        && mouseY < this.yPosition + this.height;
+                int k = this.getHoverState(this.field_146123_n);
+                GuiUtils.drawContinuousTexturedBox(
+                        buttonTextures,
+                        this.xPosition,
+                        this.yPosition,
+                        0,
+                        46 + k * 20,
+                        this.width,
+                        this.height,
+                        200,
+                        20,
+                        2,
+                        3,
+                        2,
+                        2,
+                        this.zLevel);
+                mc.renderEngine.bindTexture(new ResourceLocation("structurelib", "textures/gui/fourwayarrow2.png"));
+                int x = this.xPosition + (this.width - 12) / 2;
+                int y = this.yPosition + (this.height - 12) / 2;
+                Tessellator tessellator = Tessellator.instance;
+                tessellator.startDrawingQuads();
+                tessellator.addVertexWithUV(x, y + 12, zLevel, 0, 1);
+                tessellator.addVertexWithUV(x + 12, y + 12, zLevel, 1, 1);
+                tessellator.addVertexWithUV(x + 12, y, zLevel, 1, 0);
+                tessellator.addVertexWithUV(x, y, zLevel, 0, 0);
+                tessellator.draw();
+            }
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/RegistryOrderEntry.java

@@ -0,0 +1,77 @@
+package com.gtnewhorizon.structurelib;
+
+import java.util.List;
+
+import net.minecraft.client.gui.GuiScreen;
+
+import cpw.mods.fml.client.config.GuiConfig;
+import cpw.mods.fml.client.config.GuiConfigEntries;
+import cpw.mods.fml.client.config.IConfigElement;
+
+@SuppressWarnings({ "unchecked" })
+public final class RegistryOrderEntry extends GuiConfigEntries.CategoryEntry {
+
+    public RegistryOrderEntry(GuiConfig owningScreen, GuiConfigEntries owningEntryList,
+            IConfigElement<?> configElement) {
+        super(owningScreen, owningEntryList, configElement);
+    }
+
+    @Override
+    protected GuiScreen buildChildScreen() {
+        List<IConfigElement<?>> childElements = this.configElement.getChildElements();
+        IConfigElement<?> disabled = null, order = null;
+        for (IConfigElement<?> e : childElements) {
+            if (e.getName().equals("disabled")) disabled = e;
+            else if (e.getName().equals("ordering")) order = e;
+        }
+        if (disabled == null || order == null) {
+            throw new IllegalArgumentException("Did not find expected config entires");
+        }
+        return new GuiEditRegistryConfig(
+                this.owningScreen,
+                disabled,
+                order,
+                configElement.getName(),
+                this.owningScreen.modID,
+                null,
+                owningScreen.allRequireWorldRestart || this.configElement.requiresWorldRestart(),
+                owningScreen.allRequireMcRestart || this.configElement.requiresMcRestart(),
+                this.owningScreen.title,
+                ((this.owningScreen.titleLine2 == null ? "" : this.owningScreen.titleLine2) + " > " + this.name));
+    }
+
+    private GuiEditRegistryConfig getChildScreen() {
+        return (GuiEditRegistryConfig) childScreen;
+    }
+
+    @Override
+    public boolean saveConfigElement() {
+        GuiEditRegistryConfig c = getChildScreen();
+        if (c != null && c.isInitialized()) return c.saveConfigElements();
+        return false;
+    }
+
+    @Override
+    public boolean isChanged() {
+        GuiEditRegistryConfig c = getChildScreen();
+        return c != null && c.isInitialized() && c.isChanged();
+    }
+
+    @Override
+    public boolean isDefault() {
+        GuiEditRegistryConfig c = getChildScreen();
+        return c != null && c.isInitialized() && c.isDefault();
+    }
+
+    @Override
+    public void setToDefault() {
+        GuiEditRegistryConfig c = getChildScreen();
+        if (c != null && c.isInitialized()) c.setToDefault();
+    }
+
+    @Override
+    public void undoChanges() {
+        GuiEditRegistryConfig c = getChildScreen();
+        if (c != null && c.isInitialized()) c.undoChanges();
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/SortedRegistry.java

@@ -0,0 +1,198 @@
+package com.gtnewhorizon.structurelib;
+
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.NavigableMap;
+import java.util.Set;
+import java.util.Spliterator;
+import java.util.TreeMap;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import javax.annotation.Nullable;
+
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.server.MinecraftServer;
+
+import org.apache.commons.lang3.tuple.Pair;
+
+import com.gtnewhorizon.structurelib.net.RegistryOrderSyncMessage;
+
+import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+import cpw.mods.fml.common.gameevent.PlayerEvent;
+
+public class SortedRegistry<V> implements Iterable<V> {
+
+    static final ConcurrentHashMap<String, WeakReference<SortedRegistry<?>>> ALL_REGISTRIES = new ConcurrentHashMap<>();
+    static {
+        RegistryOrderSyncMessage.Handler.setAllRegistries(ALL_REGISTRIES);
+    }
+    private final NavigableMap<String, V> store = new TreeMap<>();
+    /**
+     * Store stuff in an array for faster iteration access than a red black tree
+     */
+    private List<V> baked = Collections.emptyList();
+
+    private final Map<UUID, Pair<List<String>, List<String>>> playerOrdering = new HashMap<>();
+    private final Map<UUID, List<V>> playerBaked = new HashMap<>();
+
+    /**
+     * Construct an unsynchronized registry
+     */
+    public SortedRegistry() {}
+
+    /**
+     * Construct a synchronized registry whose ordering will be synced to the server
+     *
+     * @param name network name
+     */
+
+    public SortedRegistry(String name) {
+        WeakReference<SortedRegistry<?>> oldValue = ALL_REGISTRIES.put(name, new WeakReference<>(this));
+        if (oldValue != null && oldValue.get() != null) {
+            throw new IllegalArgumentException("duplicate name");
+        }
+        FMLCommonHandler.instance().bus().register(this);
+    }
+
+    public static Set<String> getRegistryNames() {
+        return ALL_REGISTRIES.keySet();
+    }
+
+    public static SortedRegistry<?> getRegistry(String name) {
+        WeakReference<SortedRegistry<?>> ref = ALL_REGISTRIES.get(name);
+        return ref != null ? ref.get() : null;
+    }
+
+    static void cleanup(MinecraftServer server) {
+        @SuppressWarnings("unchecked")
+        List<EntityPlayerMP> players = server.getConfigurationManager().playerEntityList;
+        Set<UUID> onlinePlayerIDs = players.stream().map(EntityPlayerMP::getUniqueID).collect(Collectors.toSet());
+        int removed = 0;
+        for (WeakReference<SortedRegistry<?>> ref : ALL_REGISTRIES.values()) {
+            SortedRegistry<?> registry = ref.get();
+            if (registry == null) continue;
+            for (Iterator<UUID> iterator = registry.playerOrdering.keySet().iterator(); iterator.hasNext();) {
+                UUID uuid = iterator.next();
+                if (!onlinePlayerIDs.contains(uuid)) {
+                    iterator.remove();
+                    registry.playerBaked.remove(uuid);
+                    removed++;
+                }
+            }
+        }
+        if (removed > 0) {
+            StructureLib.LOGGER.debug("Removed {} registry record for logged out players", removed);
+        }
+    }
+
+    @SubscribeEvent
+    public void onPlayerLogOut(PlayerEvent.PlayerLoggedOutEvent e) {
+        playerOrdering.remove(e.player.getUniqueID());
+        playerBaked.remove(e.player.getUniqueID());
+    }
+
+    public void register(String key, V val) {
+        if (key == null || val == null) throw new NullPointerException();
+        V old = store.putIfAbsent(key, val);
+        if (old != null) {
+            throw new IllegalArgumentException("Duplicate key: " + key);
+        }
+        baked = new ArrayList<>(store.values());
+        for (Map.Entry<UUID, Pair<List<String>, List<String>>> e : playerOrdering.entrySet()) {
+            makePlayerBaked(e.getKey(), e.getValue().getKey(), e.getValue().getValue());
+        }
+    }
+
+    public void registerOrdering(EntityPlayerMP player, List<String> ordering, List<String> disabled) {
+        registerOrdering(player.getUniqueID(), ordering, disabled);
+    }
+
+    public void registerOrdering(UUID playerID, List<String> ordering, List<String> disabled) {
+        playerOrdering.put(playerID, Pair.of(ordering, disabled));
+        makePlayerBaked(playerID, ordering, disabled);
+    }
+
+    private void makePlayerBaked(UUID player, List<String> ordering, List<String> disabled) {
+        TreeMap<String, V> copy = new TreeMap<>(store);
+        for (String s : disabled) {
+            copy.remove(s);
+        }
+        List<V> b = new ArrayList<>();
+        for (String k : ordering) {
+            V v = copy.remove(k);
+            if (v != null) {
+                b.add(v);
+            }
+        }
+        b.addAll(copy.values());
+        playerBaked.put(player, b);
+    }
+
+    public int size() {
+        return store.size();
+    }
+
+    public boolean isEmpty() {
+        return store.isEmpty();
+    }
+
+    public boolean containsKey(String key) {
+        return store.containsKey(key);
+    }
+
+    public boolean containsValue(V value) {
+        return store.containsValue(value);
+    }
+
+    public V get(String key) {
+        return store.get(key);
+    }
+
+    public Iterable<V> getPlayerOrdering(@Nullable EntityPlayerMP player) {
+        if (player == null) return baked;
+        List<V> playerPreference = playerBaked.get(player.getUniqueID());
+        if (playerPreference == null) return baked;
+        return playerPreference;
+    }
+
+    public Stream<String> getPlayerOrderingKeys(@Nullable EntityPlayerMP player) {
+        if (player == null) return store.keySet().stream();
+        List<V> playerOrder = playerBaked.get(player.getUniqueID());
+        if (playerOrder == null) return store.keySet().stream();
+
+        // rebuild the order from the baked map
+        Map<V, String> reverseMap = new IdentityHashMap<>();
+        store.forEach((k, v) -> reverseMap.put(v, k));
+        return playerOrder.stream().map(reverseMap::get);
+    }
+
+    Iterable<String> getCurrentOrdering() {
+        return store.keySet();
+    }
+
+    @Override
+    public Iterator<V> iterator() {
+        return baked.iterator();
+    }
+
+    @Override
+    public void forEach(Consumer<? super V> action) {
+        baked.forEach(action);
+    }
+
+    @Override
+    public Spliterator<V> spliterator() {
+        return baked.spliterator();
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/StructureLib.java

@@ -12,18 +12,22 @@ import org.apache.logging.log4j.Logger;
 
 import com.gtnewhorizon.structurelib.block.BlockHint;
 import com.gtnewhorizon.structurelib.command.CommandConfigureChannels;
+import com.gtnewhorizon.structurelib.command.CommandRegistryDebug;
 import com.gtnewhorizon.structurelib.item.ItemBlockHint;
 import com.gtnewhorizon.structurelib.item.ItemConstructableTrigger;
 import com.gtnewhorizon.structurelib.item.ItemFrontRotationTool;
 import com.gtnewhorizon.structurelib.net.AlignmentMessage;
 import com.gtnewhorizon.structurelib.net.ErrorHintParticleMessage;
+import com.gtnewhorizon.structurelib.net.RegistryOrderSyncMessage;
 import com.gtnewhorizon.structurelib.net.SetChannelDataMessage;
 import com.gtnewhorizon.structurelib.net.UpdateHintParticleMessage;
+import com.gtnewhorizon.structurelib.util.InventoryUtility;
 import com.gtnewhorizon.structurelib.util.XSTR;
 
 import cpw.mods.fml.common.Loader;
 import cpw.mods.fml.common.Mod;
 import cpw.mods.fml.common.SidedProxy;
+import cpw.mods.fml.common.event.FMLLoadCompleteEvent;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
 import cpw.mods.fml.common.event.FMLServerStartingEvent;
 import cpw.mods.fml.common.network.NetworkRegistry;
@@ -38,7 +42,7 @@ import cpw.mods.fml.relauncher.SideOnly;
 @Mod(
         modid = StructureLibAPI.MOD_ID,
         name = "StructureLib",
-        version = "GRADLETOKEN_VERSION",
+        version = Tags.VERSION,
         acceptableRemoteVersions = "*",
         guiFactory = "com.gtnewhorizon.structurelib.GuiFactory")
 public class StructureLib {
@@ -65,6 +69,7 @@ public class StructureLib {
         net.registerMessage(UpdateHintParticleMessage.Handler.class, UpdateHintParticleMessage.class, 2, Side.CLIENT);
         net.registerMessage(SetChannelDataMessage.Handler.class, SetChannelDataMessage.class, 3, Side.SERVER);
         net.registerMessage(ErrorHintParticleMessage.Handler.class, ErrorHintParticleMessage.class, 4, Side.CLIENT);
+        net.registerMessage(RegistryOrderSyncMessage.Handler.class, RegistryOrderSyncMessage.class, 5, Side.SERVER);
 
         try {
             DEBUG_MODE = Boolean.parseBoolean(System.getProperty("structurelib.debug"));
@@ -95,6 +100,8 @@ public class StructureLib {
         }
     };
 
+    public static boolean isGTLoaded;
+
     @Mod.EventHandler
     public void preInit(FMLPreInitializationEvent e) {
         ConfigurationHandler.INSTANCE.init(e.getSuggestedConfigurationFile());
@@ -109,14 +116,23 @@ public class StructureLib {
         proxy.preInit(e);
         NetworkRegistry.INSTANCE.registerGuiHandler(instance(), new GuiHandler());
 
+        InventoryUtility.init();
         if (Loader.isModLoaded(STRUCTURECOMPAT_MODID)) {
             COMPAT = Loader.instance().getIndexedModList().get(STRUCTURECOMPAT_MODID).getMod();
         }
+
+        isGTLoaded = Loader.isModLoaded("gregtech");
+    }
+
+    @Mod.EventHandler
+    public void loadComplete(FMLLoadCompleteEvent e) {
+        proxy.loadComplete(e);
     }
 
     @Mod.EventHandler
     public void serverStarting(FMLServerStartingEvent e) {
         e.registerServerCommand(new CommandConfigureChannels());
+        e.registerServerCommand(new CommandRegistryDebug());
     }
 
     public static void addClientSideChatMessages(String... messages) {

src/main/java/com/gtnewhorizon/structurelib/StructureLibAPI.java

@@ -72,7 +72,7 @@ public class StructureLibAPI {
      */
     public static void enableInstrument(Object identifier) {
         if (isInstrumentEnabled()) throw new IllegalStateException();
-        instrument.set(instrument);
+        instrument.set(identifier);
     }
 
     /**

src/main/java/com/gtnewhorizon/structurelib/alignment/enumerable/ExtendedFacing.java

@@ -4,9 +4,18 @@ import static com.gtnewhorizon.structurelib.alignment.IAlignment.FLIPS_COUNT;
 import static com.gtnewhorizon.structurelib.alignment.IAlignment.ROTATIONS_COUNT;
 import static java.lang.Math.abs;
 import static java.util.Arrays.stream;
-import static java.util.stream.Collectors.*;
+import static java.util.stream.Collectors.collectingAndThen;
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.toMap;
+import static java.util.stream.Collectors.toSet;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Random;
 
 import net.minecraft.util.StatCollector;
 import net.minecraft.util.Vec3;

src/main/java/com/gtnewhorizon/structurelib/command/CommandConfigureChannels.java

@@ -35,7 +35,7 @@ public class CommandConfigureChannels extends CommandBase {
     }
 
     @Override
-    public List<?> addTabCompletionOptions(ICommandSender p_71516_1_, String[] p_71516_2_) {
+    public List<String> addTabCompletionOptions(ICommandSender p_71516_1_, String[] p_71516_2_) {
         if (p_71516_2_.length == 1)
             return getListOfStringsMatchingLastWord(p_71516_2_, "get", "set", "unset", "wipe", "getall");
         return null;

src/main/java/com/gtnewhorizon/structurelib/command/CommandRegistryDebug.java

@@ -0,0 +1,52 @@
+package com.gtnewhorizon.structurelib.command;
+
+import java.util.List;
+
+import net.minecraft.command.CommandBase;
+import net.minecraft.command.ICommandSender;
+import net.minecraft.command.WrongUsageException;
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.util.ChatComponentText;
+
+import com.gtnewhorizon.structurelib.SortedRegistry;
+
+public class CommandRegistryDebug extends CommandBase {
+
+    @Override
+    public String getCommandName() {
+        return "sl_registry_debug";
+    }
+
+    @Override
+    public String getCommandUsage(ICommandSender p_71518_1_) {
+        return "/sl_registry_debug <registry name>";
+    }
+
+    @Override
+    public int getRequiredPermissionLevel() {
+        return 0;
+    }
+
+    @Override
+    public List<String> addTabCompletionOptions(ICommandSender p_71516_1_, String[] p_71516_2_) {
+        if (p_71516_2_.length == 1) return getListOfStringsMatchingLastWord(
+                p_71516_2_,
+                SortedRegistry.getRegistryNames().toArray(new String[0]));
+        return null;
+    }
+
+    @Override
+    public void processCommand(ICommandSender sender, String[] args) {
+        if (args.length != 1) throw new WrongUsageException(getCommandUsage(sender));
+
+        if (!(sender instanceof EntityPlayerMP)) throw new WrongUsageException("must be a player");
+
+        EntityPlayerMP player = (EntityPlayerMP) sender;
+
+        SortedRegistry<?> registry = SortedRegistry.getRegistry(args[0]);
+        if (registry == null) throw new WrongUsageException("registry not found");
+
+        player.addChatMessage(new ChatComponentText("Current order:"));
+        registry.getPlayerOrderingKeys(player).map(ChatComponentText::new).forEach(player::addChatMessage);
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/core/StructureLibCore.java

@@ -0,0 +1,53 @@
+package com.gtnewhorizon.structurelib.core;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import com.gtnewhorizon.gtnhmixins.IEarlyMixinLoader;
+import com.gtnewhorizon.structurelib.mixins.Mixins;
+
+import cpw.mods.fml.relauncher.IFMLLoadingPlugin;
+
+public class StructureLibCore implements IFMLLoadingPlugin, IEarlyMixinLoader {
+
+    public static final Logger log = LogManager.getLogger("StructureLibCore");
+
+    @Override
+    public String getMixinConfig() {
+        return "mixins.structurelib.early.json";
+    }
+
+    @Override
+    public List<String> getMixins(Set<String> loadedCoreMods) {
+        return Mixins.getEarlyMixins(loadedCoreMods);
+    }
+
+    @Override
+    public String[] getASMTransformerClass() {
+        return new String[0];
+    }
+
+    @Override
+    public String getModContainerClass() {
+        return null;
+    }
+
+    @Override
+    public String getSetupClass() {
+        return null;
+    }
+
+    @Override
+    public void injectData(Map<String, Object> data) {
+
+    }
+
+    @Override
+    public String getAccessTransformerClass() {
+        return null;
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/event/BlockChangeListener.java

@@ -0,0 +1,11 @@
+package com.gtnewhorizon.structurelib.event;
+
+import net.minecraft.block.Block;
+import net.minecraft.world.World;
+import net.minecraft.world.chunk.Chunk;
+
+public interface BlockChangeListener {
+
+    void onBlockChange(World world, Chunk chunk, int x, int y, int z, Block oldBlock, Block newBlock, int oldMeta,
+            int newMeta);
+}

src/main/java/com/gtnewhorizon/structurelib/event/BlockChangeNotifier.java

@@ -0,0 +1,33 @@
+package com.gtnewhorizon.structurelib.event;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import net.minecraft.block.Block;
+import net.minecraft.world.World;
+import net.minecraft.world.chunk.Chunk;
+
+@SuppressWarnings("ForLoopReplaceableByForEach")
+public class BlockChangeNotifier {
+
+    private static final List<BlockChangeListener> listeners = new ArrayList<>();
+
+    public static synchronized void addListener(BlockChangeListener listener) {
+        listeners.add(listener);
+    }
+
+    public static void onBlockChange(World world, Chunk chunk, int x, int y, int z, Block oldBlock, Block newBlock,
+            int oldMeta, int newMeta) {
+        if (oldBlock == newBlock && oldMeta == newMeta) return;
+
+        if (chunk == null) {
+            chunk = world.getChunkFromBlockCoords(x, z);
+        }
+
+        final int numListeners = listeners.size();
+        for (int i = 0; i < numListeners; i++) {
+            final BlockChangeListener listener = listeners.get(i);
+            listener.onBlockChange(world, chunk, x, y, z, oldBlock, newBlock, oldMeta, newMeta);
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScreenConfigureChannels.java

@@ -25,6 +25,15 @@ import com.gtnewhorizon.structurelib.gui.GuiScrollableList.IGuiScreen;
 
 public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen {
 
+    private static final int ADD_BTN = 0;
+    private static final int UNSET_BTN = 1;
+    private static final int WIPE_BTN = 2;
+    private static final int SHOW_ERROR_BTN = 3;
+    private static final int GT_NO_HATCH_BTN = 4;
+
+    private static final String SHOW_ERROR_CHANNEL = "show_error";
+    private static final String GT_NO_HATCH_CHANNEL = "gt_no_hatch";
+
     private static final int KEY_MAX_WIDTH = 50;
     private final ItemStack trigger;
     private final GuiChannelsList list;
@@ -128,7 +137,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
 
         addButton(
                 new GuiButton(
-                        0,
+                        ADD_BTN,
                         guiLeft + 12,
                         guiTop + 157,
                         47,
@@ -136,7 +145,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
                         I18n.format("item.structurelib.constructableTrigger.gui.add")));
         addButton(
                 new GuiButton(
-                        1,
+                        UNSET_BTN,
                         guiLeft + 65,
                         guiTop + 157,
                         47,
@@ -144,13 +153,27 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
                         I18n.format("item.structurelib.constructableTrigger.gui.unset")));
         addButton(
                 new GuiButton(
-                        2,
+                        WIPE_BTN,
                         guiLeft + 118,
                         guiTop + 157,
                         47,
                         20,
                         I18n.format("item.structurelib.constructableTrigger.gui.wipe")));
 
+        addButton(
+                new GuiButton(
+                        SHOW_ERROR_BTN,
+                        StructureLib.isGTLoaded ? guiLeft + 12 : guiLeft + 52,
+                        guiTop + 180,
+                        73,
+                        20,
+                        ""));
+
+        // only show GT hatch button if GT is loaded
+        if (StructureLib.isGTLoaded) {
+            addButton(new GuiButton(GT_NO_HATCH_BTN, guiLeft + 92, guiTop + 180, 73, 20, ""));
+        }
+
         updateButtons();
     }
 
@@ -171,7 +194,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
 
     @Override
     public int getYSize() {
-        return 188;
+        return 211;
     }
 
     @Override
@@ -250,10 +273,27 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
         // STACKOVERFLOW!
         String keyText = key.getText();
         boolean existing = !StringUtils.isEmpty(keyText) && ChannelDataAccessor.hasSubChannel(trigger, keyText);
-        getButtonList().get(0).displayString = existing ? I18n.format("item.structurelib.constructableTrigger.gui.set")
+        getButtonList().get(ADD_BTN).displayString = existing
+                ? I18n.format("item.structurelib.constructableTrigger.gui.set")
                 : I18n.format("item.structurelib.constructableTrigger.gui.add");
-        getButtonList().get(0).enabled = !StringUtils.isBlank(value.getText());
-        getButtonList().get(1).enabled = existing && !StringUtils.isBlank(value.getText());
+        getButtonList().get(ADD_BTN).enabled = !StringUtils.isBlank(value.getText());
+        getButtonList().get(UNSET_BTN).enabled = existing && !StringUtils.isBlank(value.getText());
+
+        if (ChannelDataAccessor.hasSubChannel(trigger, SHOW_ERROR_CHANNEL)) {
+            getButtonList().get(SHOW_ERROR_BTN).displayString = "Hide Errors";
+        } else {
+            getButtonList().get(SHOW_ERROR_BTN).displayString = "Show Errors";
+        }
+
+        // this button only exists if GT is loaded.
+        if (StructureLib.isGTLoaded) {
+            if (ChannelDataAccessor.hasSubChannel(trigger, GT_NO_HATCH_CHANNEL)) {
+                getButtonList().get(GT_NO_HATCH_BTN).displayString = "Hatches";
+            } else {
+                getButtonList().get(GT_NO_HATCH_BTN).displayString = "No Hatch";
+            }
+        }
+
     }
 
     private int getValue() {
@@ -268,18 +308,35 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
     protected void actionPerformed(GuiButton btn) {
         if (btn == null) return;
         switch (btn.id) {
-            case 0:
+            case ADD_BTN:
                 int value = getValue();
                 if (value <= 0) return;
                 ChannelDataAccessor.setChannelData(trigger, key.getText(), value);
                 break;
-            case 1:
+            case UNSET_BTN:
                 ChannelDataAccessor.unsetChannelData(trigger, key.getText());
                 break;
-            case 2:
+            case WIPE_BTN:
                 ChannelDataAccessor.wipeChannelData(trigger);
                 break;
+            case SHOW_ERROR_BTN:
+                if (ChannelDataAccessor.hasSubChannel(trigger, SHOW_ERROR_CHANNEL)) {
+                    ChannelDataAccessor.unsetChannelData(trigger, SHOW_ERROR_CHANNEL);
+                } else {
+                    ChannelDataAccessor.setChannelData(trigger, SHOW_ERROR_CHANNEL, 1);
+                }
+                break;
+            case GT_NO_HATCH_BTN:
+                if (ChannelDataAccessor.hasSubChannel(trigger, GT_NO_HATCH_CHANNEL)) {
+                    ChannelDataAccessor.unsetChannelData(trigger, GT_NO_HATCH_CHANNEL);
+                } else {
+                    ChannelDataAccessor.setChannelData(trigger, GT_NO_HATCH_CHANNEL, 1);
+                }
+                break;
         }
+
+        updateButtons();
+
         super.actionPerformed(btn);
     }
 
@@ -350,6 +407,7 @@ public class GuiScreenConfigureChannels extends GuiScreen implements IGuiScreen
                 Entry<String, Integer> e = getElementAt(elementIndex);
                 if (e != null) {
                     ChannelDataAccessor.unsetChannelData(trigger, e.getKey());
+                    updateButtons();
                     return false;
                 }
             }

src/main/java/com/gtnewhorizon/structurelib/item/ItemConstructableTrigger.java

@@ -28,8 +28,13 @@ public class ItemConstructableTrigger extends Item {
 
     @Override
     public ItemStack onItemRightClick(ItemStack stack, World world, EntityPlayer player) {
-        if (world.isRemote && getMovingObjectPositionFromPlayer(world, player, true) == null)
-            player.openGui(StructureLib.instance(), 0, world, player.inventory.currentItem, 0, 0);
+        if (world.isRemote && getMovingObjectPositionFromPlayer(world, player, true) == null) {
+            if (player.isSneaking()) {
+                StructureLib.instance().proxy().displayConfigGUI("registries");
+            } else {
+                player.openGui(StructureLib.instance(), 0, world, player.inventory.currentItem, 0, 0);
+            }
+        }
         return super.onItemRightClick(stack, world, player);
     }
 

src/main/java/com/gtnewhorizon/structurelib/item/ItemFrontRotationTool.java

@@ -34,7 +34,7 @@ public class ItemFrontRotationTool extends Item {
 
     @Override
     @SideOnly(Side.CLIENT)
-    public void addInformation(ItemStack p_77624_1_, EntityPlayer p_77624_2_, List aList, boolean p_77624_4_) {
+    public void addInformation(ItemStack p_77624_1_, EntityPlayer p_77624_2_, List<String> aList, boolean p_77624_4_) {
         aList.add(translateToLocal("item.structurelib.frontRotationTool.desc.0")); // Triggers Front Rotation Interface
         aList.add(EnumChatFormatting.BLUE + translateToLocal("item.structurelib.frontRotationTool.desc.1")); // Rotates
                                                                                                              // only the

src/main/java/com/gtnewhorizon/structurelib/mixins/Mixins.java

@@ -0,0 +1,188 @@
+package com.gtnewhorizon.structurelib.mixins;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Supplier;
+
+import com.gtnewhorizon.structurelib.core.StructureLibCore;
+
+import cpw.mods.fml.relauncher.FMLLaunchHandler;
+
+public enum Mixins {
+
+    BLOCK_CHANGE_NOTIFIER(new Builder("Block Change Notifier").setPhase(Phase.EARLY)
+            .addMixinClasses("blockChangeNotifier.MixinForgeHooks", "blockChangeNotifier.MixinWorld")
+            .addTargetedMod(TargetedMod.VANILLA).setSide(Side.BOTH).setApplyIf(() -> true));
+
+    private final List<String> mixinClasses;
+    private final List<TargetedMod> targetedMods;
+    private final List<TargetedMod> excludedMods;
+    private final Supplier<Boolean> applyIf;
+    private final Phase phase;
+    private final Side side;
+
+    Mixins(Builder builder) {
+        this.mixinClasses = builder.mixinClasses;
+        this.targetedMods = builder.targetedMods;
+        this.excludedMods = builder.excludedMods;
+        this.applyIf = builder.applyIf;
+        this.phase = builder.phase;
+        this.side = builder.side;
+        if (this.mixinClasses.isEmpty()) {
+            throw new RuntimeException("No mixin class specified for Mixin : " + this.name());
+        }
+        if (this.targetedMods.isEmpty()) {
+            throw new RuntimeException("No targeted mods specified for Mixin : " + this.name());
+        }
+        if (this.applyIf == null) {
+            throw new RuntimeException("No ApplyIf function specified for Mixin : " + this.name());
+        }
+        if (this.phase == null) {
+            throw new RuntimeException("No Phase specified for Mixin : " + this.name());
+        }
+        if (this.side == null) {
+            throw new RuntimeException("No Side function specified for Mixin : " + this.name());
+        }
+    }
+
+    public static List<String> getEarlyMixins(Set<String> loadedCoreMods) {
+        final List<String> mixins = new ArrayList<>();
+        final List<String> notLoading = new ArrayList<>();
+        for (Mixins mixin : Mixins.values()) {
+            if (mixin.phase == Phase.EARLY) {
+                if (mixin.shouldLoad(loadedCoreMods, Collections.emptySet())) {
+                    mixins.addAll(mixin.mixinClasses);
+                } else {
+                    notLoading.addAll(mixin.mixinClasses);
+                }
+            }
+        }
+        StructureLibCore.log.info("Not loading the following EARLY mixins: {}", notLoading.toString());
+        return mixins;
+    }
+
+    public static List<String> getLateMixins(Set<String> loadedMods) {
+        // NOTE: Any targetmod here needs a modid, not a coremod id
+        final List<String> mixins = new ArrayList<>();
+        final List<String> notLoading = new ArrayList<>();
+        for (Mixins mixin : Mixins.values()) {
+            if (mixin.phase == Phase.LATE) {
+                if (mixin.shouldLoad(Collections.emptySet(), loadedMods)) {
+                    mixins.addAll(mixin.mixinClasses);
+                } else {
+                    notLoading.addAll(mixin.mixinClasses);
+                }
+            }
+        }
+        StructureLibCore.log.info("Not loading the following LATE mixins: {}", notLoading.toString());
+        return mixins;
+    }
+
+    private boolean shouldLoadSide() {
+        return side == Side.BOTH || (side == Side.SERVER && FMLLaunchHandler.side().isServer())
+                || (side == Side.CLIENT && FMLLaunchHandler.side().isClient());
+    }
+
+    private boolean allModsLoaded(List<TargetedMod> targetedMods, Set<String> loadedCoreMods, Set<String> loadedMods) {
+        if (targetedMods.isEmpty()) return false;
+
+        for (TargetedMod target : targetedMods) {
+            if (target == TargetedMod.VANILLA) continue;
+
+            // Check coremod first
+            if (!loadedCoreMods.isEmpty() && target.coreModClass != null
+                    && !loadedCoreMods.contains(target.coreModClass))
+                return false;
+            else if (!loadedMods.isEmpty() && target.modId != null && !loadedMods.contains(target.modId)) return false;
+        }
+
+        return true;
+    }
+
+    private boolean noModsLoaded(List<TargetedMod> targetedMods, Set<String> loadedCoreMods, Set<String> loadedMods) {
+        if (targetedMods.isEmpty()) return true;
+
+        for (TargetedMod target : targetedMods) {
+            if (target == TargetedMod.VANILLA) continue;
+
+            // Check coremod first
+            if (!loadedCoreMods.isEmpty() && target.coreModClass != null
+                    && loadedCoreMods.contains(target.coreModClass))
+                return false;
+            else if (!loadedMods.isEmpty() && target.modId != null && loadedMods.contains(target.modId)) return false;
+        }
+
+        return true;
+    }
+
+    private boolean shouldLoad(Set<String> loadedCoreMods, Set<String> loadedMods) {
+        return (shouldLoadSide() && applyIf.get()
+                && allModsLoaded(targetedMods, loadedCoreMods, loadedMods)
+                && noModsLoaded(excludedMods, loadedCoreMods, loadedMods));
+    }
+
+    private static class Builder {
+
+        private final String name;
+        private final List<String> mixinClasses = new ArrayList<>();
+        private final List<TargetedMod> targetedMods = new ArrayList<>();
+        private final List<TargetedMod> excludedMods = new ArrayList<>();
+        private Supplier<Boolean> applyIf = null;
+        private Phase phase = null;
+        private Side side = null;
+
+        public Builder(String name) {
+            this.name = name;
+        }
+
+        public Builder addMixinClasses(String... mixinClasses) {
+            this.mixinClasses.addAll(Arrays.asList(mixinClasses));
+            return this;
+        }
+
+        public Builder setPhase(Phase phase) {
+            if (this.phase != null) {
+                throw new RuntimeException("Trying to define Phase twice for " + this.name);
+            }
+            this.phase = phase;
+            return this;
+        }
+
+        public Builder setSide(Side side) {
+            if (this.side != null) {
+                throw new RuntimeException("Trying to define Side twice for " + this.name);
+            }
+            this.side = side;
+            return this;
+        }
+
+        public Builder setApplyIf(Supplier<Boolean> applyIf) {
+            this.applyIf = applyIf;
+            return this;
+        }
+
+        public Builder addTargetedMod(TargetedMod mod) {
+            this.targetedMods.add(mod);
+            return this;
+        }
+
+        public Builder addExcludedMod(TargetedMod mod) {
+            this.excludedMods.add(mod);
+            return this;
+        }
+    }
+
+    private enum Side {
+        BOTH,
+        CLIENT,
+        SERVER
+    }
+
+    private enum Phase {
+        EARLY,
+        LATE,
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/mixins/TargetedMod.java

@@ -0,0 +1,30 @@
+package com.gtnewhorizon.structurelib.mixins;
+
+import cpw.mods.fml.common.Mod;
+
+public enum TargetedMod {
+
+    VANILLA("Minecraft", null);
+
+    /** The "name" in the {@link Mod @Mod} annotation */
+    public final String modName;
+    /** Class that implements the IFMLLoadingPlugin interface */
+    public final String coreModClass;
+    /** The "modid" in the {@link Mod @Mod} annotation */
+    public final String modId;
+
+    TargetedMod(String modName, String coreModClass) {
+        this(modName, coreModClass, null);
+    }
+
+    TargetedMod(String modName, String coreModClass, String modId) {
+        this.modName = modName;
+        this.coreModClass = coreModClass;
+        this.modId = modId;
+    }
+
+    @Override
+    public String toString() {
+        return "TargetedMod{modName='" + modName + "', coreModClass='" + coreModClass + "', modId='" + modId + "'}";
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/mixins/early/blockChangeNotifier/MixinForgeHooks.java

@@ -0,0 +1,44 @@
+package com.gtnewhorizon.structurelib.mixins.early.blockChangeNotifier;
+
+import net.minecraft.block.Block;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.item.ItemStack;
+import net.minecraft.world.World;
+import net.minecraftforge.common.ForgeHooks;
+import net.minecraftforge.common.util.BlockSnapshot;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import com.gtnewhorizon.structurelib.event.BlockChangeNotifier;
+import com.llamalad7.mixinextras.sugar.Local;
+
+@Mixin(ForgeHooks.class)
+public class MixinForgeHooks {
+
+    @Inject(
+            method = "onPlaceItemIntoWorld",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/World;markAndNotifyBlock(IIILnet/minecraft/world/chunk/Chunk;Lnet/minecraft/block/Block;Lnet/minecraft/block/Block;I)V",
+                    shift = At.Shift.AFTER),
+            remap = false)
+    private static void onBlockChange(ItemStack itemstack, EntityPlayer player, World world, int x, int y, int z,
+            int side, float hitX, float hitY, float hitZ, CallbackInfoReturnable<Boolean> cir,
+            @Local(name = "blocksnapshot") BlockSnapshot blocksnapshot, @Local(name = "newBlock") Block newBlock,
+            @Local(name = "metadata") int newMetadata) {
+        BlockChangeNotifier.onBlockChange(
+                world,
+                null,
+                blocksnapshot.x,
+                blocksnapshot.y,
+                blocksnapshot.z,
+                blocksnapshot.replacedBlock,
+                newBlock,
+                blocksnapshot.meta,
+                newMetadata);
+    }
+
+}

src/main/java/com/gtnewhorizon/structurelib/mixins/early/blockChangeNotifier/MixinWorld.java

@@ -0,0 +1,55 @@
+package com.gtnewhorizon.structurelib.mixins.early.blockChangeNotifier;
+
+import net.minecraft.block.Block;
+import net.minecraft.world.World;
+import net.minecraft.world.chunk.Chunk;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import com.gtnewhorizon.structurelib.event.BlockChangeNotifier;
+import com.llamalad7.mixinextras.sugar.Local;
+import com.llamalad7.mixinextras.sugar.Share;
+import com.llamalad7.mixinextras.sugar.ref.LocalIntRef;
+import com.llamalad7.mixinextras.sugar.ref.LocalRef;
+
+@Mixin(World.class)
+public class MixinWorld {
+
+    @Inject(
+            method = "Lnet/minecraft/world/World;setBlock(IIILnet/minecraft/block/Block;II)Z",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/World;markAndNotifyBlock(IIILnet/minecraft/world/chunk/Chunk;Lnet/minecraft/block/Block;Lnet/minecraft/block/Block;I)V",
+                    shift = At.Shift.AFTER,
+                    remap = false))
+    public void setBlockObserve(int x, int y, int z, Block newBlock, int newMeta, int flags,
+            CallbackInfoReturnable<Boolean> cir, @Local(name = "block1") Block originalBlock,
+            @Share("originalMeta") LocalIntRef originalMeta, @Share("chunk") LocalRef<Chunk> chunkLocalRef) {
+        BlockChangeNotifier.onBlockChange(
+                (World) ((Object) (this)),
+                chunkLocalRef.get(),
+                x,
+                y,
+                z,
+                originalBlock,
+                newBlock,
+                originalMeta.get(),
+                newMeta);
+    }
+
+    @Inject(
+            method = "Lnet/minecraft/world/World;setBlock(IIILnet/minecraft/block/Block;II)Z",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/chunk/Chunk;func_150807_a(IIILnet/minecraft/block/Block;I)Z",
+                    shift = At.Shift.BEFORE))
+    public void captureChunkAndOriginalMetadata(int x, int y, int z, Block blockIn, int metadataIn, int flags,
+            CallbackInfoReturnable<Boolean> cir, @Local(name = "chunk") Chunk chunk,
+            @Share("originalMeta") LocalIntRef originalMeta, @Share("chunk") LocalRef<Chunk> chunkLocalRef) {
+        chunkLocalRef.set(chunk);
+        originalMeta.set(chunk.getBlockMetadata(x & 15, y, z & 15));
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/net/RegistryOrderSyncMessage.java

@@ -0,0 +1,77 @@
+package com.gtnewhorizon.structurelib.net;
+
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+
+import com.gtnewhorizon.structurelib.SortedRegistry;
+
+import cpw.mods.fml.common.network.ByteBufUtils;
+import cpw.mods.fml.common.network.simpleimpl.IMessage;
+import cpw.mods.fml.common.network.simpleimpl.IMessageHandler;
+import cpw.mods.fml.common.network.simpleimpl.MessageContext;
+import io.netty.buffer.ByteBuf;
+
+public class RegistryOrderSyncMessage implements IMessage {
+
+    private String name;
+    private List<String> order;
+    private List<String> disabled;
+
+    public RegistryOrderSyncMessage() {}
+
+    public RegistryOrderSyncMessage(String name, List<String> order, List<String> disabled) {
+        this.name = name;
+        this.order = order;
+        this.disabled = disabled;
+    }
+
+    @Override
+    public void fromBytes(ByteBuf buf) {
+        name = ByteBufUtils.readUTF8String(buf);
+        int size = ByteBufUtils.readVarInt(buf, 2);
+        order = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            order.add(ByteBufUtils.readUTF8String(buf));
+        }
+        size = ByteBufUtils.readVarInt(buf, 2);
+        disabled = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            disabled.add(ByteBufUtils.readUTF8String(buf));
+        }
+    }
+
+    @Override
+    public void toBytes(ByteBuf buf) {
+        ByteBufUtils.writeUTF8String(buf, name);
+        ByteBufUtils.writeVarInt(buf, order.size(), 2);
+        for (String s : order) {
+            ByteBufUtils.writeUTF8String(buf, s);
+        }
+        ByteBufUtils.writeVarInt(buf, disabled.size(), 2);
+        for (String s : disabled) {
+            ByteBufUtils.writeUTF8String(buf, s);
+        }
+    }
+
+    public static class Handler implements IMessageHandler<RegistryOrderSyncMessage, IMessage> {
+
+        private static ConcurrentHashMap<String, WeakReference<SortedRegistry<?>>> ALL_REGISTRIES;
+
+        public static void setAllRegistries(ConcurrentHashMap<String, WeakReference<SortedRegistry<?>>> r) {
+            if (ALL_REGISTRIES == null) ALL_REGISTRIES = r;
+        }
+
+        @Override
+        public IMessage onMessage(RegistryOrderSyncMessage message, MessageContext ctx) {
+            if (ALL_REGISTRIES == null) return null;
+            WeakReference<SortedRegistry<?>> ref = ALL_REGISTRIES.get(message.name);
+            if (ref == null) return null;
+            SortedRegistry<?> r = ref.get();
+            if (r == null) return null;
+            r.registerOrdering(ctx.getServerHandler().playerEntity, message.order, message.disabled);
+            return null;
+        }
+    }
+}

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureDefinition.java

@@ -12,6 +12,7 @@ import net.minecraft.world.World;
 
 import com.gtnewhorizon.structurelib.StructureLib;
 import com.gtnewhorizon.structurelib.StructureLibAPI;
+import com.gtnewhorizon.structurelib.alignment.constructable.ChannelDataAccessor;
 import com.gtnewhorizon.structurelib.alignment.constructable.ISurvivalConstructable;
 import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
 
@@ -50,7 +51,7 @@ import com.gtnewhorizon.structurelib.alignment.enumerable.ExtendedFacing;
  * itself.</li>
  * <li>The "C" position would be the number of blocks between you and controller, not counting controller itself.</li>
  * </ul>
- * 
+ *
  * @param <T> Type of the context object. Usually this will be the multiblock controller.
  */
 public interface IStructureDefinition<T> {
@@ -72,7 +73,7 @@ public interface IStructureDefinition<T> {
 
     /**
      * Run a structure check.
-     * 
+     *
      * @param object              context object. usually multiblock controller.
      * @param piece               the structure piece's string identifier.
      * @param world               the world object this check takes place in.
@@ -107,7 +108,7 @@ public interface IStructureDefinition<T> {
 
     /**
      * Spawn hint particles. Should not be called on server side.
-     * 
+     *
      * @param object         context object. usually multiblock controller.
      * @param piece          the structure piece's string identifier.
      * @param world          the world object this check takes place in.
@@ -320,7 +321,7 @@ public interface IStructureDefinition<T> {
 
     /**
      * Low level utility.
-     * 
+     *
      * @param object                                  context object. usually multiblock controller.
      * @param trigger                                 The trigger item that contains channel data.
      * @param elements                                the structure piece
@@ -394,6 +395,10 @@ public interface IStructureDefinition<T> {
                         basePositionC,
                         ignoreBlockUnloaded((e, w, x, y, z, a, b, c) -> {
                             e.spawnHint(object, world, x, y, z, trigger);
+                            if (ChannelDataAccessor.hasSubChannel(trigger, "show_error")
+                                    && !e.couldBeValid(object, world, x, y, z, trigger)) {
+                                StructureLibAPI.markHintParticleError(StructureLib.getCurrentPlayer(), world, x, y, z);
+                            }
                             return true;
                         }),
                         "spawnHint");
@@ -420,7 +425,7 @@ public interface IStructureDefinition<T> {
 
     /**
      * Create a new instance of builder.
-     * 
+     *
      * @param <T> type of context object
      */
     static <T> StructureDefinition.Builder<T> builder() {

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElement.java

@@ -32,6 +32,16 @@ public interface IStructureElement<T> {
 
     boolean check(T t, World world, int x, int y, int z);
 
+    /**
+     * Pure (stateless and side effect free) function to test if current block could be valid. Used to give user hints
+     * about incorrectly placed blocks given a controller and trigger item. If couldBeValid(...) == false for a set of
+     * channels, with those same tiers, check(...) == false. Not required, defaults to true which is always safe but
+     * won't give the user error hints.
+     */
+    default boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+        return true;
+    }
+
     boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger);
 
     boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger);
@@ -185,6 +195,11 @@ public interface IStructureElement<T> {
                 return IStructureElement.this.check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return IStructureElement.this.couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return IStructureElement.this.spawnHint(t, world, x, y, z, trigger);

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementChain.java

@@ -31,6 +31,16 @@ public interface IStructureElementChain<T> extends IStructureElement<T> {
         return false;
     }
 
+    @Override
+    default boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+        for (IStructureElement<T> fallback : fallbacks()) {
+            if (fallback.couldBeValid(t, world, x, y, z, trigger)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @Override
     default boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
         for (IStructureElement<T> fallback : fallbacks()) {
@@ -62,7 +72,8 @@ public interface IStructureElementChain<T> extends IStructureElement<T> {
             if (e == null) continue;
             if (predicate == null) predicate = e.getPredicate();
             else predicate = predicate.or(e.getPredicate());
-            is.add(e.getStacks());
+            Iterable<ItemStack> stacks = e.getStacks();
+            if (stacks != null) is.add(stacks);
         }
         if (predicate == null) return null;
         return new BlocksToPlace(predicate, Iterables.concat(is));

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementCheckOnly.java

@@ -14,6 +14,11 @@ public interface IStructureElementCheckOnly<T> extends IStructureElement<T> {
         return false;
     }
 
+    @Override
+    default boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+        return true;
+    }
+
     @Override
     default boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
         return false;

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureNavigate.java

@@ -17,6 +17,11 @@ interface IStructureNavigate<T> extends IStructureElement<T> {
         return true;
     }
 
+    @Override
+    default boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+        return true;
+    }
+
     @Override
     default boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
         return true;

src/main/java/com/gtnewhorizon/structurelib/structure/LazyStructureElement.java

@@ -32,6 +32,11 @@ class LazyStructureElement<T> implements IStructureElementDeferred<T> {
         return get(t).check(t, world, x, y, z);
     }
 
+    @Override
+    public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+        return get(t).couldBeValid(t, world, x, y, z, trigger);
+    }
+
     @Override
     public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
         return get(t).placeBlock(t, world, x, y, z, trigger);

src/main/java/com/gtnewhorizon/structurelib/structure/StructureDefinition.java

@@ -1,8 +1,15 @@
 package com.gtnewhorizon.structurelib.structure;
 
-import static com.gtnewhorizon.structurelib.structure.StructureUtility.*;
+import static com.gtnewhorizon.structurelib.structure.StructureUtility.isAir;
+import static com.gtnewhorizon.structurelib.structure.StructureUtility.notAir;
+import static com.gtnewhorizon.structurelib.structure.StructureUtility.step;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 import com.gtnewhorizon.structurelib.util.Vec3Impl;

src/main/java/com/gtnewhorizon/structurelib/structure/StructureUtility.java

@@ -2,9 +2,26 @@ package com.gtnewhorizon.structurelib.structure;
 
 import static java.lang.Integer.MIN_VALUE;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
 import java.util.Map.Entry;
-import java.util.function.*;
+import java.util.Objects;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.BiPredicate;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
 
 import javax.annotation.Nullable;
 
@@ -138,6 +155,11 @@ public class StructureUtility {
             return world.isAirBlock(x, y, z);
         }
 
+        @Override
+        public boolean couldBeValid(Object t, World world, int x, int y, int z, ItemStack trigger) {
+            return check(t, world, x, y, z);
+        }
+
         @Override
         public boolean spawnHint(Object o, World world, int x, int y, int z, ItemStack trigger) {
             StructureLibAPI.hintParticle(world, x, y, z, StructureLibAPI.getBlockHint(), 13);
@@ -169,6 +191,11 @@ public class StructureUtility {
             return !world.isAirBlock(x, y, z);
         }
 
+        @Override
+        public boolean couldBeValid(Object t, World world, int x, int y, int z, ItemStack trigger) {
+            return check(t, world, x, y, z);
+        }
+
         @Override
         public boolean spawnHint(Object o, World world, int x, int y, int z, ItemStack trigger) {
             StructureLibAPI.hintParticle(world, x, y, z, StructureLibAPI.getBlockHint(), 14);
@@ -208,6 +235,11 @@ public class StructureUtility {
             return false;
         }
 
+        @Override
+        public boolean couldBeValid(Object t, World world, int x, int y, int z, ItemStack trigger) {
+            return check(t, world, x, y, z);
+        }
+
         @Override
         public boolean spawnHint(Object o, World world, int x, int y, int z, ItemStack trigger) {
             StructureLibAPI.hintParticle(world, x, y, z, StructureLibAPI.getBlockHint(), 15);
@@ -462,6 +494,11 @@ public class StructureUtility {
                 return true;
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, StructureLibAPI.getBlockHint(), meta);
@@ -482,6 +519,11 @@ public class StructureUtility {
                 return true;
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, icons.get());
@@ -502,6 +544,11 @@ public class StructureUtility {
                 return true;
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticleTinted(world, x, y, z, icons.get(), RGBa);
@@ -577,6 +624,9 @@ public class StructureUtility {
      * Implementation wise, this allows a block only when we don't yet have a tier, or the block at that location has
      * the same tier as we already have.
      * <p>
+     * Notice that if your tier extractor function returns null on any (Block, meta) pair, then it means this block is
+     * rejected, since null can never be a valid tier.
+     * <p>
      * There is yet no TileEntity counterpart of this utility. Feel free to submit a PR to add it.
      * <p>
      * For most typical use cases, you will NOT want to return notSet from your tierExtractor. If you do so, we will
@@ -620,7 +670,8 @@ public class StructureUtility {
      * </pre>
      *
      * @param tierExtractor a function to extract tier info from a block. This function can return null and will never
-     *                      be passed a null block or an invalid block meta.
+     *                      be passed a null block or an invalid block meta. If this function returns null, then the
+     *                      block would be considered invalid.
      * @param allKnownTiers A list of all known tiers as of calling. Can be empty or null. No hint will be spawned if
      *                      empty or null. Cannot have null elements. First element denotes the most primitive tier.
      *                      Last element denotes the most advanced tier. If not all tiers are available at definition
@@ -646,9 +697,23 @@ public class StructureUtility {
             }
 
             private Pair<Block, Integer> getHint(ItemStack trigger) {
+                if (hints.isEmpty()) return null;
                 return hints.get(Math.min(Math.max(trigger.stackSize, 1), hints.size()) - 1);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                Pair<Block, Integer> hint = getHint(trigger);
+                if (hint == null) return true;
+                TIER hintTier = tierExtractor.convert(hint.getKey(), hint.getValue());
+                Block block = world.getBlock(x, y, z);
+                int meta = world.getBlockMetadata(x, y, z);
+                TIER worldTier = tierExtractor.convert(block, meta);
+
+                // if the block is in the same tier as the hint block, this could be valid
+                return Objects.equals(hintTier, worldTier);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 Pair<Block, Integer> hint = getHint(trigger);
@@ -746,6 +811,11 @@ public class StructureUtility {
                 return world.getBlock(x, y, z) == getBlock() && (wildcard || world.getBlockMetadata(x, y, z) == meta);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 if (getBlock() == null) return error().spawnHint(t, world, x, y, z, trigger);
@@ -820,10 +890,16 @@ public class StructureUtility {
 
             @Override
             public boolean check(T t, World world, int x, int y, int z) {
-                if (init()) return world.getBlock(x, y, z) != block && world.getBlockMetadata(x, y, z) == meta;
+                if (init()) return world.getBlock(x, y, z) == block && world.getBlockMetadata(x, y, z) == meta;
                 else return fallback.check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                if (init()) return world.getBlock(x, y, z) == block && world.getBlockMetadata(x, y, z) == meta;
+                else return fallback.couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 if (init()) {
@@ -900,6 +976,11 @@ public class StructureUtility {
                 return blocsMap.getOrDefault(worldBlock, MIN_VALUE) == worldBlock.getDamageValue(world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -937,6 +1018,11 @@ public class StructureUtility {
                         .contains(worldBlock.getDamageValue(world, x, y, z));
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -961,6 +1047,11 @@ public class StructureUtility {
                 return block == worldBlock && meta == worldBlock.getDamageValue(world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return check(t, world, x, y, z);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -995,6 +1086,13 @@ public class StructureUtility {
                 return iBlockAdder.apply(t, worldBlock, worldBlock.getDamageValue(world, x, y, z));
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                // calling iBlockAdder can potentially modify external state
+                // therefore we assume this can always be valid.
+                return true;
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -1028,6 +1126,11 @@ public class StructureUtility {
                     return blocsMap.getOrDefault(worldBlock, MIN_VALUE) == worldBlock.getDamageValue(world, x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     ((ICustomBlockSetting) defaultBlock).setBlock(world, x, y, z, defaultMeta);
@@ -1072,6 +1175,11 @@ public class StructureUtility {
                     return blocsMap.getOrDefault(worldBlock, MIN_VALUE) == worldBlock.getDamageValue(world, x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     world.setBlock(x, y, z, defaultBlock, defaultMeta, 2);
@@ -1137,6 +1245,11 @@ public class StructureUtility {
                             .contains(worldBlock.getDamageValue(world, x, y, z));
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     ((ICustomBlockSetting) defaultBlock).setBlock(world, x, y, z, defaultMeta);
@@ -1182,6 +1295,11 @@ public class StructureUtility {
                             .contains(worldBlock.getDamageValue(world, x, y, z));
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     world.setBlock(x, y, z, defaultBlock, defaultMeta, 2);
@@ -1239,6 +1357,11 @@ public class StructureUtility {
                     return block == worldBlock && meta == worldBlock.getDamageValue(world, x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     ((ICustomBlockSetting) defaultBlock).setBlock(world, x, y, z, defaultMeta);
@@ -1266,6 +1389,11 @@ public class StructureUtility {
                     return block == worldBlock && meta == worldBlock.getDamageValue(world, x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     world.setBlock(x, y, z, defaultBlock, defaultMeta, 2);
@@ -1302,6 +1430,11 @@ public class StructureUtility {
                     return block == world.getBlock(x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     ((ICustomBlockSetting) defaultBlock).setBlock(world, x, y, z, defaultMeta);
@@ -1329,6 +1462,11 @@ public class StructureUtility {
                     return block == world.getBlock(x, y, z);
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    return check(t, world, x, y, z);
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     world.setBlock(x, y, z, defaultBlock, defaultMeta, 2);
@@ -1395,6 +1533,13 @@ public class StructureUtility {
                     return iBlockAdder.apply(t, worldBlock, worldBlock.getDamageValue(world, x, y, z));
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    // calling iBlockAdder can potentially modify external state
+                    // therefore we assume this can always be valid.
+                    return true;
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     ((ICustomBlockSetting) defaultBlock).setBlock(world, x, y, z, defaultMeta);
@@ -1434,6 +1579,13 @@ public class StructureUtility {
                     return iBlockAdder.apply(t, worldBlock, worldBlock.getDamageValue(world, x, y, z));
                 }
 
+                @Override
+                public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                    // calling iBlockAdder can potentially modify external state
+                    // therefore we assume this can always be valid.
+                    return true;
+                }
+
                 @Override
                 public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                     world.setBlock(x, y, z, defaultBlock, defaultMeta, 2);
@@ -1489,6 +1641,13 @@ public class StructureUtility {
                 return iTileAdder.apply(t, tileEntity);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                // calling iTileAdder can potentially modify external state
+                // therefore we assume this can always be valid.
+                return true;
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -1515,6 +1674,13 @@ public class StructureUtility {
                 return tileClass.isInstance(tileEntity) && iTileAdder.test(t, tileClass.cast(tileEntity));
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                // calling iTileAdder can potentially modify external state
+                // therefore we assume this can always be valid.
+                return true;
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 StructureLibAPI.hintParticle(world, x, y, z, hintBlock, hintMeta);
@@ -1548,6 +1714,11 @@ public class StructureUtility {
                 return check;
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return element.couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return element.placeBlock(t, world, x, y, z, trigger);
@@ -1599,6 +1770,11 @@ public class StructureUtility {
                 return check;
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return element.couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return element.placeBlock(t, world, x, y, z, trigger);
@@ -1657,6 +1833,13 @@ public class StructureUtility {
                 return predicate.test(t) && downstream.check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                // this COULD potentially impact external state
+                // but predicate really should not have side effects
+                return predicate.test(t) && downstream.couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return predicate.test(t) && downstream.spawnHint(t, world, x, y, z, trigger);
@@ -1753,6 +1936,11 @@ public class StructureUtility {
                 return elem.check(t.getCurrentContext(), world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return elem.couldBeValid(t.getCurrentContext(), world, x, y, z, trigger);
+            }
+
             @Override
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return elem.spawnHint(t.getCurrentContext(), world, x, y, z, trigger);
@@ -1840,6 +2028,11 @@ public class StructureUtility {
                 return to.get().check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return to.get().couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return to.get().placeBlock(t, world, x, y, z, trigger);
@@ -1893,6 +2086,11 @@ public class StructureUtility {
                 return to.apply(t).check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return to.apply(t).couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return to.apply(t).placeBlock(t, world, x, y, z, trigger);
@@ -2105,6 +2303,11 @@ public class StructureUtility {
                 return to.apply(t, null).check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return to.apply(t, trigger).couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return to.apply(t, trigger).placeBlock(t, world, x, y, z, trigger);
@@ -2297,6 +2500,11 @@ public class StructureUtility {
                 return toCheck.apply(t).check(t, world, x, y, z);
             }
 
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return to.apply(t, trigger).couldBeValid(t, world, x, y, z, trigger);
+            }
+
             @Override
             public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return to.apply(t, trigger).placeBlock(t, world, x, y, z, trigger);
@@ -2541,6 +2749,11 @@ public class StructureUtility {
                 return backing.check(t, world, x, y, z);
             }
 
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                ItemStack newTrigger = ChannelDataAccessor.withChannel(trigger, channel);
+                return backing.couldBeValid(t, world, x, y, z, newTrigger);
+            }
+
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 ItemStack newTrigger = ChannelDataAccessor.withChannel(trigger, channel);
                 // We know spawnHint will only be called on client side, so the lack of player isn't quite an issue

src/main/java/com/gtnewhorizon/structurelib/util/InventoryUtility.java

@@ -14,7 +14,10 @@
  */
 package com.gtnewhorizon.structurelib.util;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -30,6 +33,7 @@ import net.minecraft.inventory.InventoryEnderChest;
 import net.minecraft.item.ItemStack;
 
 import com.gtnewhorizon.gtnhlib.util.map.ItemStackMap;
+import com.gtnewhorizon.structurelib.SortedRegistry;
 import com.gtnewhorizon.structurelib.util.InventoryUtility.ItemStackExtractor.APIType;
 import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
 
@@ -38,12 +42,13 @@ import com.gtnewhorizon.structurelib.util.ItemStackPredicate.NBTMode;
  */
 public class InventoryUtility {
 
-    private static final SortedRegistry<ItemStackExtractor> stackExtractors = new SortedRegistry<>();
+    private static final SortedRegistry<ItemStackExtractor> stackExtractors = new SortedRegistry<>("stackExtractors");
     private static final List<Predicate<? super EntityPlayerMP>> enableEnder = new CopyOnWriteArrayList<>();
     /**
      * The remove() of the Iterable returned must be implemented!
      */
-    private static final SortedRegistry<InventoryProvider<?>> inventoryProviders = new SortedRegistry<>();
+    private static final SortedRegistry<InventoryProvider<?>> inventoryProviders = new SortedRegistry<>(
+            "inventoryProviders");
 
     static {
         inventoryProviders.register("5000-main-inventory", new InventoryProvider<InventoryIterable<InventoryPlayer>>() {
@@ -102,8 +107,8 @@ public class InventoryUtility {
         registerInventoryProvider(key, newInventoryProvider(extractor));
     }
 
-    public static Iterator<? extends ItemStackExtractor> getStackExtractors() {
-        return stackExtractors.iterator();
+    public static Iterator<? extends ItemStackExtractor> getStackExtractors(EntityPlayerMP player) {
+        return stackExtractors.getPlayerOrdering(player).iterator();
     }
 
     public static <Inv extends IInventory> InventoryProvider<InventoryIterable<Inv>> newInventoryProvider(
@@ -165,7 +170,7 @@ public class InventoryUtility {
             boolean simulate, int count) {
         ItemStackCounterImpl store = new ItemStackCounterImpl();
         int sum = 0;
-        for (InventoryProvider<?> provider : inventoryProviders) {
+        for (InventoryProvider<?> provider : inventoryProviders.getPlayerOrdering(player)) {
             sum += takeFromPlayer(player, predicate, simulate, count - sum, store, provider, null);
             if (sum >= count) return store.getStore();
         }
@@ -186,7 +191,7 @@ public class InventoryUtility {
         int count = filter.stackSize;
         ItemStackPredicate predicate = ItemStackPredicate.from(filter, NBTMode.EXACT);
         ItemStackCounterImpl store = new ItemStackCounterImpl();
-        for (InventoryProvider<?> provider : inventoryProviders) {
+        for (InventoryProvider<?> provider : inventoryProviders.getPlayerOrdering(player)) {
             sum += takeFromPlayer(player, predicate, simulate, count - sum, store, provider, filter);
             if (sum >= count) return sum;
         }
@@ -212,7 +217,7 @@ public class InventoryUtility {
      * @param predicate item stack filter
      * @param simulate  whether to do removal
      * @param count     let's hope int size is enough...
-     * @param recursive do recursive lookup using {@link #getStackExtractors() stack extractors}
+     * @param recursive do recursive lookup using {@link #getStackExtractors(EntityPlayerMP) stack extractors}
      * @return amount taken. never negative nor bigger than count...
      */
     public static Map<ItemStack, Integer> takeFromInventory(Iterable<ItemStack> inv, Predicate<ItemStack> predicate,
@@ -252,7 +257,7 @@ public class InventoryUtility {
                 if (found == count) return count;
             }
             if (!recursive) continue;
-            for (ItemStackExtractor f : stackExtractors) {
+            for (ItemStackExtractor f : stackExtractors.getPlayerOrdering(player)) {
                 boolean end = f.isAPIImplemented(APIType.IS_VALID_SOURCE);
                 if (!f.isValidSource(stack, player)) continue;
                 if (filter != null && f.isAPIImplemented(APIType.EXTRACT_ONE_STACK)) {
@@ -268,6 +273,10 @@ public class InventoryUtility {
         return found;
     }
 
+    public static void init() {
+        // dummy method to init static final fields
+    }
+
     public interface OptimizedExtractor {
 
         /**

src/main/java/com/gtnewhorizon/structurelib/util/SortedRegistry.java

@@ -1,6 +1,12 @@
 package com.gtnewhorizon.structurelib.util;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NavigableMap;
+import java.util.Spliterator;
+import java.util.TreeMap;
 import java.util.function.Consumer;
 
 public class SortedRegistry<V> implements Iterable<V> {

src/main/javadoc/overview.html

@@ -251,5 +251,42 @@ The code for placeBlock() and spawnHint() will be left as an exercise for the re
 <p>
     Please refer to {@link com.gtnewhorizon.structurelib.StructureEvent} to see what events are available.
 </p>
+<h1>Extending Inventory Utility</h1>
+{@link com.gtnewhorizon.structurelib.util.InventoryUtility} is how structurelib survival autoplace pulls item for autoplacing.
+It has two key concepts: inventory providers and stack extractors.
+<p>
+    Inventory Providers are classes that retrieve an Iterable of ItemStacks for examination, given an EntityPlayerMP as identifier.
+    They are also responsible for marking the relevant item container as dirty, so changes can be commited to disk properly when world save happens.
+    Examples include: main player inventory, vanilla ender chest, baubles inventory. StructureLib comes with main player inventory and vanilla ender chest built in.
+</p>
+<p>
+    Stack Extractors are classes that retrieve items from another item.
+    Examples include: Forestry backpacks, ME network over ME Wireless Terminals.
+</p>
+<p>
+Both of these are managed internally by {@link com.gtnewhorizon.structurelib.SortedRegistry}.
+By default, elements registered will be sorted in lexicographical order in ascending order.
+However, facilities in StructureLib will allow an end user to tweak these registries as their wish.
+They can disable, reorder, reenable any element within the registry, either in game, at main menu or with the game stopped,
+Their changes will be synced to server as well, should they be playing on a dedicated server.
+</p>
+<p>
+    This has the following important implications
+</p>
+<ul>
+    <li>Not all inventory providers or stack extractors may be called during a survival autoplace session</li>
+    <li>One player could have stack extractor 001 ordered before 002, while the other having a completely reversed order</li>
+</ul>
+Therefore, if your stack extractor can somehow correlate with aonther one, make sure it still works if the calling order is inverted.
+At the very least, inform the player about this ordering constraint.
+A future StructrueLib refactor to specify this dependency info is possible, but the chance is low.
+<h2>Localization</h2>
+Both of these would show up in config GUI of StructureLib. Structurelib uses the following localization keys in that GUI.
+<ul>
+    <li><code>structurelib.sortedregistry.inventoryproviders.&lt;registry_key&gt;</code>: This is the name shown on the button for inventory providers. If this is not provided, then registry_key will be used instead.</li>
+    <li><code>structurelib.sortedregistry.inventoryproviders.&lt;registry_key&gt;.tooltip</code>: This is the tooltip shown when user hover over the button for inventory providers. If this is not provided, then no explicit tooltip will be shown.</li>
+    <li><code>structurelib.sortedregistry.stackextractors.&lt;registry_key&gt;</code>: This is the name shown on the button for stack extractors. If this is not provided, then registry_key will be used instead.</li>
+    <li><code>structurelib.sortedregistry.stackextractors.&lt;registry_key&gt;.tooltip</code>: This is the tooltip shown when user hover over the button for stack extractors. If this is not provided, then no explicit tooltip will be shown.</li>
+</ul>
 </BODY>
 </HTML>

src/main/resources/assets/structurelib/lang/en_US.lang

@@ -172,3 +172,19 @@ structurelib.config.client.hologram.maxCoexisting=Max Coexisting Holograms
 structurelib.config.client.hologram.maxCoexisting.tooltip=Number of holograms that can coexist. Usually all hints generated by one right click belongs to one hologram. An attempt will be made to prune old holograms when a new hologram is about to be projected and this limit would be exceeded.
 structurelib.config.client.hologram.removeColliding=Remove Colliding Holograms
 structurelib.config.client.hologram.removeColliding.tooltip=Whether an attempt will be made to remove any existing hologram that collides with a new hologram.
+
+structurelib.config.registries=Sorted Registries
+structurelib.config.registries.tooltip=Sorted Registry is how StructureLib internally keep track of certain features. Each individual elements may be reordered, disabled and enabled at user's command. Changes will be synced to server if needed.\nThis gui can also be accessed in game by shift right clicking air with Multiblock Structure Hologram Projector.
+structurelib.config.registries.stackextractors=Stack Extractors
+structurelib.config.registries.stackextractors.tooltip=Controls which inventory-from-stack functions are enabled during survival autoplace
+structurelib.config.registries.inventoryproviders=Inventory Providers
+structurelib.config.registries.inventoryproviders.tooltip=Controls which inventories functions are enabled during survival autoplace
+
+structurelib.configgui.enabled=Enabled Entry
+structurelib.configgui.disabled=Disabled Entry
+structurelib.configgui.drag.tooltip=Drag this button to reorder this element.
+
+structurelib.sortedregistry.inventoryproviders.5000-main-inventory=Main Player Inventory
+structurelib.sortedregistry.inventoryproviders.5000-main-inventory.tooltip=36 slots of item in your main inventory. Armor slots excluded.
+structurelib.sortedregistry.inventoryproviders.7000-ender-inventory=Ender Chest Inventory
+structurelib.sortedregistry.inventoryproviders.7000-ender-inventory.tooltip=Links to your vanilla ender chest inventory. Require at least one "ender backpack like" item in main inventory to work.

src/main/resources/assets/structurelib/lang/zh_CN.lang

@@ -172,3 +172,19 @@ structurelib.config.client.hologram.maxCoexisting=最多可以同时存在的全
 structurelib.config.client.hologram.maxCoexisting.tooltip=这决定最多可以同时存在多少台机器的全息投影。一般一次使用全息投影仪右键生成的所有机器结构细节被视为一个全息投影。当同时存在多个全息投影，并超过此数量时，再次使用全息投影仪会移除旧有的全息投影。
 structurelib.config.client.hologram.removeColliding=移除冲突的全息投影
 structurelib.config.client.hologram.removeColliding.tooltip=当新的全息投影与已存在的全息投影冲突时，开启此选项时会移除已存在的全息投影。
+
+structurelib.config.registries=注册表
+structurelib.config.registries.tooltip=StructureLib 使用注册表来管理其部分功能。每个注册表中的每一个元素都可以被单独排序、禁用。需要时，注册表的内容将被同步至服务端。
+structurelib.config.registries.stackextractors=物品提取器
+structurelib.config.registries.stackextractors.tooltip=该注册表控制在生存模式自动放置时，如何从物品（如林业背包）提取库存。
+structurelib.config.registries.inventoryproviders=物品栏定位
+structurelib.config.registries.inventoryproviders.tooltip=该注册表控制在生存模式自动放置时，可用的物品栏来源。
+
+structurelib.configgui.enabled=已启用
+structurelib.configgui.disabled=已禁用
+structurelib.configgui.drag.tooltip=拖动该按钮以重排。
+
+structurelib.sortedregistry.inventoryproviders.5000-main-inventory=玩家物品栏
+structurelib.sortedregistry.inventoryproviders.5000-main-inventory.tooltip=不包括护甲栏以外的36格。
+structurelib.sortedregistry.inventoryproviders.7000-ender-inventory=末影箱
+structurelib.sortedregistry.inventoryproviders.7000-ender-inventory.tooltip=当前玩家的末影箱。需要在主物品栏中存在类似于末影背包的东西才会实际生效。

src/main/resources/mixins.structurelib.early.json

@@ -0,0 +1,8 @@
+{
+  "required": true,
+  "minVersion": "0.8.5-GTNH",
+  "package": "com.gtnewhorizon.structurelib.mixins.early",
+  "refmap": "mixins.structurelib.refmap.json",
+  "target": "@env(DEFAULT)",
+  "compatibilityLevel": "JAVA_8"
+}

src/main/resources/mixins.structurelib.json

@@ -0,0 +1,8 @@
+{
+  "required": true,
+  "minVersion": "0.8.5-GTNH",
+  "package": "com.gtnewhorizon.structurelib.mixins",
+  "refmap": "mixins.structurelib.refmap.json",
+  "target": "@env(DEFAULT)",
+  "compatibilityLevel": "JAVA_8"
+}

src/main/resources/mixins.structurelib.late.json

@@ -0,0 +1,8 @@
+{
+  "required": true,
+  "minVersion": "0.8.5-GTNH",
+  "package": "com.gtnewhorizon.structurelib.mixins.late",
+  "refmap": "mixins.structurelib.refmap.json",
+  "target": "@env(DEFAULT)",
+  "compatibilityLevel": "JAVA_8"
+}

src/main/resources/structurelib_at.cfg

@@ -0,0 +1 @@
+public net.minecraft.client.gui.GuiSlot func_148136_c(IIII)V # overlayBackground