CacheHashMap:

-New class extending from the HashMap class, only takes CacheHashMap.CachedObject as values, which itself is a template class.
-On every call to get(), it goes through its values and removes any that are past a set age in millis.

ClientCache:
-New class with static CacheHashMap and function to get image data, will do more caching later on.

src/main/java/noppes/npcs/client/ClientCache.java

@@ -0,0 +1,16 @@
+package noppes.npcs.client;
+
+import noppes.npcs.client.renderer.customitem.ImageData;
+import noppes.npcs.util.CacheHashMap;
+
+public class ClientCache {
+    private static final CacheHashMap<String, CacheHashMap.CachedObject<ImageData>> imageDataCache = new CacheHashMap<>(10*1000);
+
+    public static ImageData getImageData(String directory) {
+        if (!imageDataCache.containsKey(directory)) {
+            ImageData imageData = new ImageData(directory);
+            imageDataCache.put(directory, new CacheHashMap.CachedObject<>(imageData));
+        }
+        return imageDataCache.get(directory).getObject();
+    }
+}