LRUCache.java
/*
* Copyright (c) 2005-2011, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file except
* in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.wso2.carbon.governance.api.cache;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class LRUCache<K, V> extends LinkedHashMap<K, V> {
int maxSize;
private ReadWriteLock lock;
public LRUCache(int maxSize) {
super(maxSize + 1, 1, false);
this.maxSize = maxSize;
this.lock = new ReentrantReadWriteLock();
}
@Override
public V get(Object key) {
lock.readLock().lock();
try {
return super.get(key);
} finally {
lock.readLock().unlock();
}
}
@Override
public V put(K key, V value) {
lock.writeLock().lock();
try {
return super.put(key, value);
} finally {
lock.writeLock().unlock();
}
}
@Override
public V remove(Object key) {
lock.writeLock().lock();
try {
return super.remove(key);
} finally {
lock.writeLock().unlock();
}
}
@Override
public void clear() {
lock.writeLock().lock();
try {
super.clear();
} finally {
lock.writeLock().unlock();
}
}
@Override
protected boolean removeEldestEntry(Map.Entry eldest) {
boolean remove = size() > maxSize;
if (remove) {
handleRemovableEntry(eldest);
}
return remove;
}
protected void handleRemovableEntry(Map.Entry<K, V> entry) {
}
public void exclusiveLock() {
lock.writeLock().lock();
}
public void release() {
lock.writeLock().unlock();
}
}