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- /* *******************************************************************
- * Copyright (c) 2017 Contributors
- * All rights reserved.
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- * ******************************************************************/package org.aspectj.util;
-
- import java.lang.ref.ReferenceQueue;
- import java.lang.ref.SoftReference;
- import java.util.AbstractMap;
- import java.util.Collections;
- import java.util.HashMap;
- import java.util.Map;
-
- public class SoftHashMap<K,V> extends AbstractMap<K,V> {
- private Map<K, SpecialValue> map;
- private ReferenceQueue<? super V> rq = new ReferenceQueue();
-
- public SoftHashMap() {
- this.map = new HashMap<K,SpecialValue>();
- }
-
- class SpecialValue extends SoftReference<V> {
- private final K key;
-
- SpecialValue(K k, V v) {
- super(v, rq);
- this.key = k;
- }
- }
-
- @SuppressWarnings("unchecked")
- private void processQueue() {
- SpecialValue sv = null;
- while ((sv = (SpecialValue)rq.poll()) != null) {
- map.remove(sv.key);
- }
- }
-
- @Override
- public V get(Object key) {
- SpecialValue ref = map.get(key);
- if (ref == null) {
- map.remove(key);
- return null;
- }
- V value = ref.get();
- if (value == null) {
- map.remove(ref.key);
- return null;
- }
- return value;
- }
-
- @Override
- public V put(K k, V v) {
- processQueue();
- SpecialValue sv = new SpecialValue(k, v);
- SpecialValue result = map.put(k, sv);
- return (result == null ? null : result.get());
- }
-
- @Override
- public java.util.Set<Map.Entry<K,V>> entrySet() {
- if (map.isEmpty()) { return Collections.<K,V>emptyMap().entrySet(); }
- Map<K,V> currentContents = new HashMap<K,V>();
- for (Map.Entry<K,SpecialValue> entry: map.entrySet()) {
- V currentValueForEntry = entry.getValue().get();
- if (currentValueForEntry != null) {
- currentContents.put(entry.getKey(), currentValueForEntry);
- }
- }
- return currentContents.entrySet();
- }
-
- @Override
- public void clear() {
- processQueue();
- map.clear();
- }
-
- @Override
- public int size() {
- processQueue();
- return map.size();
- }
-
- @Override
- public V remove(Object k) {
- processQueue();
- SpecialValue ref = map.remove(k);
- if (ref == null) {
- return null;
- }
- return ref.get();
- }
- }
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