Attempted to make cache system thread compatible.

src/main/java/ca/recrown/islandsurvivalcraft/caching/Cache.java

@@ -14,7 +14,7 @@ public class Cache <CacheValueType> {
         this.maxCacheSize = maxCacheSize;
     }
 
-    public CacheValue<CacheValueType> retrieveCache(Identifier identifier) {        
+    public synchronized CacheValue<CacheValueType> retrieveCache(Identifier identifier) {        
         if (dataCache.containsKey(identifier)) {
             ids.remove(identifier);
             dataCache.get(identifier);

src/main/java/ca/recrown/islandsurvivalcraft/caching/CacheValue.java

@@ -1,9 +1,9 @@
 package ca.recrown.islandsurvivalcraft.caching;
 
 public class CacheValue <ValueType> {
-    private ValueType value;
+    private volatile ValueType value;
     protected final Identifier identifier;
-    private boolean fresh = true;
+    private volatile boolean fresh = true;
 
     public CacheValue(Identifier identifier) {
         this.identifier = identifier;
@@ -13,9 +13,10 @@ public class CacheValue <ValueType> {
         return fresh;
     }
 
-    public void setValue(ValueType value) {
+    public synchronized void setValue(ValueType value) {
         this.fresh = false;
         this.value = value;
+        identifier.usage ++;
     }
 
     public ValueType getValue() {

src/main/java/ca/recrown/islandsurvivalcraft/caching/CoordinateIdentifier.java

@@ -5,10 +5,12 @@ import java.util.Objects;
 public class CoordinateIdentifier extends Identifier {
     private final int x;
     private final int y;
+    private final int hash;
 
     public CoordinateIdentifier(int x, int y) {
         this.x = x;
         this.y = y;
+        hash = Objects.hash(x, y);
     }
 
     @Override
@@ -22,7 +24,20 @@ public class CoordinateIdentifier extends Identifier {
 
     @Override
     public int hashCode() {
-        return Objects.hash(x, y);
+        return hash;
     }
 
+    /**
+     * @return the x
+     */
+    public int getX() {
+        return x;
+    }
+
+    /**
+     * @return the y
+     */
+    public int getY() {
+        return y;
+    }
 }

src/main/java/ca/recrown/islandsurvivalcraft/caching/Identifier.java

@@ -1,7 +1,7 @@
 package ca.recrown.islandsurvivalcraft.caching;
 
 public abstract class Identifier implements Comparable<Identifier> {
-    protected int usage;
+    protected volatile int usage;
 
     @Override
     public abstract boolean equals(Object obj);
@@ -10,7 +10,7 @@ public abstract class Identifier implements Comparable<Identifier> {
     public abstract int hashCode();
 
     @Override
-    public int compareTo(Identifier o) {
+    public synchronized int compareTo(Identifier o) {
         return usage - o.usage;
     }
 }