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正文代码
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
/**
* 注册一个或多个消费线程的Map.
* 当缓存中存在数据就跑已注册的线程
* <p>
* 注册的线程中需要做删除该map中的元素处理
* </p>
* 否则就如果为空，就等待.
*
* @param <K>
* the key type
* @param <V>
* the value type
* @author ming.peng
* @date 2013-12-19
* @since 4.0.0
*/
@SuppressWarnings("serial")
public class ConsumConcurrentHashMap<K, V> extends ConcurrentHashMap<K, V> {
/** The lock, 用于当前线程changed值改变时同步所用. */
private final ReentrantLock lock = new ReentrantLock();
/** Condition for waiting takes */
private final Condition notEmpty = lock.newCondition();
/** 默认设置线程池,用于执行任务, 线程执行器. */
private ExecutorService executor = Executors.newFixedThreadPool(5);
/** The runnables. */
private final List<ConsumerRunnable> runnables = new CopyOnWriteArrayList<ConsumerRunnable>();
/**
* Instantiates a new drives concurrent hash map.
*/
public ConsumConcurrentHashMap() {
super();
}
/**
* Instantiates a new drives concurrent hash map.
*
* @param initialCapacity
* the initial capacity
* @param loadFactor
* the load factor
* @param concurrencyLevel
* the concurrency level
*/
public ConsumConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel) {
super(initialCapacity, loadFactor, concurrencyLevel);
}
/**
* Instantiates a new drives concurrent hash map.
*
* @param initialCapacity
* the initial capacity
* @param loadFactor
* the load factor
*/
public ConsumConcurrentHashMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Instantiates a new drives concurrent hash map.
*
* @param initialCapacity
* the initial capacity
*/
public ConsumConcurrentHashMap(int initialCapacity) {
super(initialCapacity);
}
/**
* Instantiates a new drives concurrent hash map.
*
* @param m
* the m
*/
public ConsumConcurrentHashMap(Map<? extends K, ? extends V> m) {
super(m);
}
/**
* Gets the executor.
*
* @return the executor
*/
public ExecutorService getExecutor() {
return executor;
}
/**
* Sets the executor.
*
* @param executor
* the new executor
*/
public void setExecutor(ExecutorService executor) {
this.executor = executor;
}
/**
* Regsiter runnable.
*
* @param runnable
* the runnable
*/
public void regsiterRunnable(Runnable runnable) {
ConsumerRunnable run = new ConsumerRunnable(runnable);
this.runnables.add(run);
executor.execute(run);
}
/**
* Regsiter runnable.
*
* @param runName
* the run name
* @param runnable
* the runnable
*/
public void regsiterRunnable(String runName, Runnable runnable) {
ConsumerRunnable run = new ConsumerRunnable(runName, runnable);
this.runnables.add(run);
executor.execute(run);
}
/**
* 删除线程，但不会立马结束线程
* Removes the runnable.
*
* @param runnable
* the runnable
*/
public void removeRunnable(String runName) {
for (ConsumerRunnable run : this.runnables) {
if (null != run.getRunName() && run.getRunName().equals(runName)) {
run.setActive(false); // 标记线程退出
this.runnables.remove(run); // 把线程对象从队列中删除
}
}
}
/**
* 删除线程，但不会立马结束线程
* Removes the runnable.
*
* @param runnable
* the runnable
*/
public void removeRunnable(Runnable runnable) {
for (ConsumerRunnable run : this.runnables) {
if (run.getRunnable().equals(runnable)) {
run.setActive(false); // 标记线程退出
this.runnables.remove(run); // 把线程对象从队列中删除
}
}
}
/*
* (non-Javadoc)
*
* @see java.util.concurrent.ConcurrentHashMap#put(java.lang.Object,
* java.lang.Object)
*/
@Override
public V put(K key, V value) {
V v = super.put(key, value);
notifyConsumerRunnables();
return v;
}
/*
* (non-Javadoc)
*
* @see java.util.concurrent.ConcurrentHashMap#putIfAbsent(java.lang.Object,
* java.lang.Object)
*/
@Override
public V putIfAbsent(K key, V value) {
V v = super.putIfAbsent(key, value);
notifyConsumerRunnables();
return v;
}
/*
* (non-Javadoc)
*
* @see java.util.concurrent.ConcurrentHashMap#putAll(java.util.Map)
*/
@Override
public void putAll(Map<? extends K, ? extends V> m) {
super.putAll(m);
notifyConsumerRunnables();
}
/**
* notify consumer threads
*/
private void notifyConsumerRunnables() {
lock.lock();
try{
if (this.size() > this.runnables.size() * 1000) {
notEmpty.signalAll();
} else {
notEmpty.signal();
}
}finally{
lock.unlock();
}
}
/**
* 消费线程
*
* @author rocca.peng@hunteron.com
* @Description
* @Date 2015年7月17日 下午6:00:46
*/
protected final class ConsumerRunnable implements Runnable {
/** The run name. */
private String runName;
/** The runnable. */
private Runnable runnable;
/** The isNow. 表示是否继续执行任务, false表示不执行任务，true执行 */
private boolean isNow = true;
/** The isActive, 标识线程是否运行, false停止运行， true运行. */
private boolean isActive = true;
/**
* Instantiates a new drives runnable.
*/
private ConsumerRunnable() {
}
/**
* Instantiates a new drives runnable.
*
* @param runnable
* the runnable
*/
private ConsumerRunnable(Runnable runnable) {
super();
this.runnable = runnable;
}
/**
* Instantiates a new drives runnable.
*
* @param runName
* the run name
* @param runnable
* the runnable
*/
private ConsumerRunnable(String runName, Runnable runnable) {
super();
this.runnable = runnable;
this.runName = runName;
}
/** 将注册进来的runnable执行#run()方法,完成后看是否需要有补充机制. */
public void run() {
while (this.isActive) {
lock.lock();
try {
if (ConsumConcurrentHashMap.this.isEmpty()) {
notEmpty.await();
}
if (isNow) {
runnable.run();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
public boolean isNow() {
return isNow;
}
public void setNow(boolean isNow) {
this.isNow = isNow;
}
/**
* Gets the Active.
*
* @return
*/
public boolean isActive() {
return isActive;
}
/**
* Sets the Active.
*
* @param isActive
*/
public void setActive(boolean isActive) {
this.isActive = isActive;
}
/**
* Gets the run name.
*
* @return the run name
*/
public String getRunName() {
return runName;
}
/**
* Sets the run name.
*
* @param runName
* the new run name
*/
public void setRunName(String runName) {
this.runName = runName;
}
/**
* Gets the runnable.
*
* @return the runnable
*/
public Runnable getRunnable() {
return runnable;
}
/**
* Sets the runnable.
*
* @param runnable
* the new runnable
*/
public void setRunnable(Runnable runnable) {
this.runnable = runnable;
}
}
/**
* 停止所有任务,正在执行的任务会继续执行,关闭线程池
*/
public void shutdown() {
// 将所有线程标记结束
for (ConsumerRunnable run : runnables) {
run.setActive(false);
}
// 如果存在休眠的线程，就唤醒所有线程，执行完毕，退出run方法
lock.lock();
try{
notEmpty.signalAll();
}finally{
lock.unlock();
}
// 关闭线程执行器
executor.shutdown();
}
/**
* 停止所有任务,尝试停止正在执行的线程，关闭线程池
*/
public List<Runnable> shutdownNow() {
// 将所有线程标记结束
for (ConsumerRunnable run : runnables) {
run.setActive(false);
run.setNow(false); // 在结束时是否执行任务
}
// 如果存在休眠的线程，就唤醒所有线程，执行完毕，退出run方法
lock.lock();
try{
notEmpty.signalAll();
}finally{
lock.unlock();
}
// 关闭线程执行器
return executor.shutdownNow();
}
}
2. 测试
import java.util.Map.Entry;
import java.util.Random;
import java.util.UUID;
import org.apache.commons.lang3.RandomStringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Test {
private static final Logger logger = LoggerFactory.getLogger(Test.class);
private static final ConsumConcurrentHashMap<String, String> map = new ConsumConcurrentHashMap<>();
public static void main(String[] args) {
Runnable runnable = new Runnable() {
Random r = new Random();
@Override
public void run() {
long s = System.currentTimeMillis();
long e = 0l;
while((e = System.currentTimeMillis()) - s < 10 * 60 * 1000) {
map.put(UUID.randomUUID().toString(), RandomStringUtils.randomAlphanumeric(5));
// try {
// long nextLong = r.nextInt(10);
// Thread.sleep(nextLong);
// } catch (InterruptedException es) {
// es.printStackTrace();
// }
}
}
};
Thread thread = new Thread(runnable);
thread.start();
map.regsiterRunnable(new Runnable() {
private int i = 0;
@Override
public void run() {
i++;
for (Entry<String, String> entry : map.entrySet()) {
logger.info(i + "\t" + entry.getKey() + "\t" + entry.getValue() + "\t" + map.size());
map.remove(entry.getKey());
}
}
});
map.regsiterRunnable(new Runnable() {
private int i = 0;
@Override
public void run() {
i++;
for (Entry<String, String> entry : map.entrySet()) {
logger.info(i + "\t" + entry.getKey() + "\t" + entry.getValue() + "\t" + map.size());
map.remove(entry.getKey());
}
}
});
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
map.shutdown();
}
}
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原文地址：http://my.oschina.net/mingpeng/blog/480852
