| /*
|
| * Copyright 1999-2011 Alibaba Group.
|
| *
|
| * Licensed 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 com.alibaba.dubbo.common.utils; |
| |
| import java.util.LinkedHashMap; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| public class LRUCache<K, V> extends LinkedHashMap<K, V> { |
| |
| private static final long serialVersionUID = -5167631809472116969L; |
| |
| private static final float DEFAULT_LOAD_FACTOR = 0.75f; |
| |
| private static final int DEFAULT_MAX_CAPACITY = 1000; |
| |
| private volatile int maxCapacity; |
| |
| private final Lock lock = new ReentrantLock(); |
| |
| public LRUCache() { |
| this(DEFAULT_MAX_CAPACITY); |
| } |
| |
| public LRUCache(int maxCapacity) { |
| super(16, DEFAULT_LOAD_FACTOR, true); |
| this.maxCapacity = maxCapacity; |
| } |
| |
| @Override |
| protected boolean removeEldestEntry(java.util.Map.Entry<K, V> eldest) { |
| return size() > maxCapacity; |
| } |
| |
| @Override |
| public boolean containsKey(Object key) { |
| try { |
| lock.lock(); |
| return super.containsKey(key); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public V get(Object key) { |
| try { |
| lock.lock(); |
| return super.get(key); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public V put(K key, V value) { |
| try { |
| lock.lock(); |
| return super.put(key, value); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public V remove(Object key) { |
| try { |
| lock.lock(); |
| return super.remove(key); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public int size() { |
| try { |
| lock.lock(); |
| return super.size(); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public void clear() { |
| try { |
| lock.lock(); |
| super.clear(); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| public int getMaxCapacity() { |
| return maxCapacity; |
| } |
| |
| public void setMaxCapacity(int maxCapacity) { |
| this.maxCapacity = maxCapacity; |
| } |
| |
| } |