com.star.cache.simple.SimpleCache Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of utils Show documentation
some utility class for java develop
The newest version!
package com.star.cache.simple;

import com.star.cache.Cache;
import com.star.exception.CacheException;

import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * 缓存简单实现
 *
 * @param  键
 * @param  值
 * @author starhq
 */
public class SimpleCache implements Cache {

    /**
     * 池，存放缓存
     */
    private final Map CACHE = new WeakHashMap<>();

    /**
     * 锁
     */
    private final ReentrantReadWriteLock cacheLock = new ReentrantReadWriteLock(false);
    /**
     * 写锁
     */
    private final ReentrantReadWriteLock.WriteLock writeLock = cacheLock.writeLock();
    /**
     * 读锁
     */
    private final ReentrantReadWriteLock.ReadLock readLock = cacheLock.readLock();

    /**
     * 从缓存中获得值
     *
     * @param key 键
     * @return 值
     * @throws CacheException 缓存异常
     */
    @Override
    public V get(K key) throws CacheException {
        readLock.lock();
        try {
            return CACHE.get(key);
        } finally {
            readLock.unlock();
        }
    }

    /**
     * 数据存入缓存
     *
     * @param key   键
     * @param value 值
     * @return 值
     * @throws CacheException 缓存异常
     */
    @Override
    public V put(K key, V value) throws CacheException {
        writeLock.lock();
        try {
            CACHE.put(key, value);
        } finally {
            writeLock.unlock();
        }
        return value;
    }

    /**
     * 删除缓存
     *
     * @param key 键
     * @return 从缓存删除的值
     * @throws CacheException 缓存异常
     */
    @Override
    public V remove(K key) throws CacheException {
        writeLock.lock();
        try {
            return CACHE.remove(key);
        } finally {
            writeLock.unlock();
        }
    }

    /**
     * 清空缓存
     *
     * @throws CacheException 缓存异常
     */
    @Override
    public void clear() throws CacheException {
        writeLock.lock();
        try {
            CACHE.clear();
        } finally {
            writeLock.unlock();
        }
    }
}