/**
* Copyright (C) 2012 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.util.map;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
/**
* Implementation of {@link Map2} that holds its values by weak reference. Keys are held by strong reference.
*
* @param <K1> key 1 type
* @param <K2> key 2 type
* @param <V> value type
*/
public class WeakValueHashMap2<K1, K2, V> extends ReferenceHashMap2<K1, K2, V> {
private static final class Ref<K1, K2, V> extends WeakReference<V> {
private final ReferenceHashMap2<K1, K2, V>.ReferenceMap _map;
private final K2 _key;
private Ref(final V value, final ReferenceHashMap2<K1, K2, V>.ReferenceMap map, final K2 key, final ReferenceQueue<V> queue) {
super(value, queue);
_map = map;
_key = key;
}
private void housekeep() {
_map.housekeep(_key, this);
}
}
public WeakValueHashMap2(final KeyStrategy key1Strategy) {
super(key1Strategy);
}
@Override
protected Reference<? extends V> createReference(final ReferenceHashMap2<K1, K2, V>.ReferenceMap map, final K2 key, final V value) {
return new Ref<K1, K2, V>(value, map, key, getGarbageQueue());
}
@SuppressWarnings("unchecked")
@Override
protected void housekeep(final Reference<? extends V> ref) {
((Ref<K1, K2, V>) ref).housekeep();
}
}