Cache now no longer locked from reading while writing.

Fixed another case where writing is followed by consecutive reading.

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

@@ -22,14 +22,15 @@ class CacheUsageStack<K, V> {
     }
 
     private void removeValueFromStack(CacheValue<K, V> value) {
+        if (value == null) throw new IllegalStateException("Current size is supposed to be " + size);
         if (value.front != null) {
             value.front.back = value.back;
-        } else if (first == value) {
+        } else {
             first = value.back;
         }
         if (value.back != null) {
             value.back.front = value.front;
-        } else if (last == value) {
+        } else {
             last = value.front;
         }
         value.front = null;
@@ -66,6 +67,7 @@ class CacheUsageStack<K, V> {
         lock.lock();
         try {
             addValueToStackTop(value);
+            value.detached = false;
         } finally {
             lock.unlock();
         }
@@ -98,4 +100,15 @@ class CacheUsageStack<K, V> {
     public int size() {
         return size;
     }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBulder = new StringBuilder();
+        CacheValue<K, V> current = first;
+        while (current != null) {
+            stringBulder.append(first + "\n");
+            current = current.back;
+        }
+        return stringBulder.toString();
+    }
 }

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

@@ -19,5 +19,6 @@ class CacheValue<KeyType, ValueType> {
     /**
      * Whether or not this value is detached from the cache's hashmap.
      */
-    public volatile boolean detached;
+    public volatile boolean detached = true;
+
 }