dubbo LRUCache 源码

dubbo LRUCache 代码

文件路径：/dubbo-common/src/main/java/org/apache/dubbo/common/utils/LRUCache.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.dubbo.common.utils;

import java.util.LinkedHashMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * A 'least recently used' cache based on LinkedHashMap.
 *
 * @param <K> key
 * @param <V> value
 */
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 final Lock lock = new ReentrantLock();
    private volatile int maxCapacity;

    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) {
        lock.lock();
        try {
            return super.containsKey(key);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public V get(Object key) {
        lock.lock();
        try {
            return super.get(key);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public V put(K key, V value) {
        lock.lock();
        try {
            return super.put(key, value);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public V remove(Object key) {
        lock.lock();
        try {
            return super.remove(key);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public int size() {
        lock.lock();
        try {
            return super.size();
        } finally {
            lock.unlock();
        }
    }

    @Override
    public void clear() {
        lock.lock();
        try {
            super.clear();
        } finally {
            lock.unlock();
        }
    }

    public void lock() {
        lock.lock();
    }

    public void releaseLock() {
        lock.unlock();
    }

    public int getMaxCapacity() {
        return maxCapacity;
    }

    public void setMaxCapacity(int maxCapacity) {
        this.maxCapacity = maxCapacity;
    }

}

相关信息

dubbo 源码目录

相关文章

dubbo AnnotationUtils 源码

dubbo ArrayUtils 源码

dubbo Assert 源码

dubbo AtomicPositiveInteger 源码

dubbo CIDRUtils 源码

dubbo CharSequenceComparator 源码

dubbo ClassHelper 源码

dubbo ClassLoaderResourceLoader 源码

dubbo ClassUtils 源码

dubbo CollectionUtils 源码