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package org.apache.wink.common.internal.utils;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * 

* Concurrent implementation of the SimpleMap interface. The idea behind this * implementation that get is called more frequently than put or clear, * therefore ReentrantReadWriteLock is used: get is read operation, while put * and clear are write operations. * * @param * @param * @see java.util.concurrent.locks.ReentrantReadWriteLock */ public class SimpleConcurrentMap implements SimpleMap { private final Lock readersLock; private final Lock writersLock; private final Map map; public SimpleConcurrentMap() { this(new HashMap()); } /** * Provides the map implementation. Pay attention that get method is * synchronized using the read lock, therefore it must not change the * entire collection. * * @param map */ public SimpleConcurrentMap(Map map) { this.map = map; ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); readersLock = readWriteLock.readLock(); writersLock = readWriteLock.writeLock(); } public V get(K key) { readersLock.lock(); try { return map.get(key); } finally { readersLock.unlock(); } } public V put(K key, V val) { writersLock.lock(); try { return map.put(key, val); } finally { writersLock.unlock(); } } public void clear() { writersLock.lock(); try { map.clear(); } finally { writersLock.unlock(); } } }





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