Add support for custom entity selectors in commands (#3356)

src/main/java/net/minecraftforge/event/EntitySelectorEvent.java

@@ -0,0 +1,121 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.event;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.Lists;
+import net.minecraft.command.EntitySelector;
+import net.minecraft.command.ICommandSender;
+import net.minecraft.entity.Entity;
+import net.minecraft.util.math.Vec3d;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.fml.common.eventhandler.Event;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * EntitySelectorEvent is fired whenever Minecraft collects entity selectors.
+ * This happens (one or multiple times) when you use something like @a[gamemode=1] in a command.<br>
+ * This event is fired via {@link ForgeEventFactory#gatherEntitySelectors(Map, String, ICommandSender, Vec3d)},
+ * which is executed in {@link net.minecraft.command.EntitySelector#matchEntities(ICommandSender, String, Class)}<br>
+ * <br>
+ * This event is not cancelable and does not have a result.<br>
+ * <br>
+ * This event is fired on the {@link MinecraftForge#EVENT_BUS}
+ */
+public class EntitySelectorEvent extends Event
+{
+
+    private final Map<String, String> map;
+    private final String mainSelector;
+    private final ICommandSender sender;
+    private final Vec3d position;
+    private final List<Predicate<Entity>> selectors;
+
+    public EntitySelectorEvent(Map<String, String> map, String mainSelector, ICommandSender sender, Vec3d position)
+    {
+        this.map = map;
+        this.mainSelector = mainSelector;
+        this.sender = sender;
+        this.position = position;
+        selectors = Lists.newArrayList();
+    }
+
+    /**
+     * Add your custom selector.
+     * It is recommend to use "modid:name", if checking for own arguments, to avoid inter-mod interference (e.g.  "@a[Forge:timeplayed=100]").
+     *
+     * @param selector Your custom predicate
+     */
+    public void addPredicate(Predicate<Entity> selector)
+    {
+        if (selector == null)
+        {
+            throw new NullPointerException("Attempted to add null predicate as entity selector");
+        }
+        selectors.add(selector);
+    }
+
+    /**
+     * @return The main selector used (e.g. 'a' for all players or 'e' for all entities)
+     */
+    public String getMainSelector()
+    {
+        return mainSelector;
+    }
+
+    /**
+     * Example: "@a[test=true]" would result in a map with "test"=>"true"
+     *
+     * @return The argument map. Maps all given argument names with its value.
+     */
+    public Map<String, String> getArgumentMap()
+    {
+        return map;
+    }
+
+    /**
+     * See {@link EntitySelector#getPosFromArguments(Map, Vec3d)}
+     *
+     * @return A position either specified in the selector arguments or by the players position.
+     */
+    public Vec3d getPosition()
+    {
+        return position;
+    }
+
+    /**
+     * @return The sender of the command.
+     */
+    public ICommandSender getSender()
+    {
+        return sender;
+    }
+
+    /**
+     * @return The list of added custom selectors
+     */
+    List<Predicate<Entity>> getSelectors()
+    {
+        return selectors;
+    }
+
+}

src/main/java/net/minecraftforge/event/ForgeEventFactory.java

@@ -22,9 +22,12 @@ package net.minecraftforge.event;
 import java.io.File;
 import java.util.EnumSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Random;
 
+import com.google.common.base.Predicate;
 import net.minecraft.block.state.IBlockState;
+import net.minecraft.command.ICommandSender;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLiving;
 import net.minecraft.entity.EntityLivingBase;
@@ -242,6 +245,13 @@ public class ForgeEventFactory
         return event.getDisplayname();
     }
 
+    public static List<Predicate<Entity>> gatherEntitySelectors(Map<String, String> map, String mainSelector, ICommandSender sender, Vec3d position)
+    {
+        EntitySelectorEvent event=new EntitySelectorEvent(map, mainSelector, sender, position);
+        MinecraftForge.EVENT_BUS.post(event);
+        return event.getSelectors();
+    }
+
     public static float fireBlockHarvesting(List<ItemStack> drops, World world, BlockPos pos, IBlockState state, int fortune, float dropChance, boolean silkTouch, EntityPlayer player)
     {
         BlockEvent.HarvestDropsEvent event = new BlockEvent.HarvestDropsEvent(world, pos, state, fortune, dropChance, drops, player, silkTouch);