java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock Java Examples

@Override
public long count(String cacheName, OpType opType)
{
    ReadLock readLock = getReadLock(cacheName);
    readLock.lock();
    try
    {
        Map<OpType, OperationStats> cacheStats = cacheToStatsMap.get(cacheName);
        if (cacheStats == null)
        {
            throw new NoStatsForCache(cacheName);
        }
        OperationStats opStats = cacheStats.get(opType);
        return opStats.getCount();
    }
    finally
    {
        readLock.unlock();
    }
}
 

@Override
public double meanTime(String cacheName, OpType opType)
{
    ReadLock readLock = getReadLock(cacheName);
    readLock.lock();
    try
    {
        Map<OpType, OperationStats> cacheStats = cacheToStatsMap.get(cacheName);
        if (cacheStats == null)
        {
            throw new NoStatsForCache(cacheName);
        }
        OperationStats opStats = cacheStats.get(opType);
        return opStats.meanTime();
    }
    finally
    {
        readLock.unlock();
    }
}
 

@Override
public double hitMissRatio(String cacheName)
{
    ReadLock readLock = getReadLock(cacheName);
    readLock.lock();
    try
    {
        Map<OpType, OperationStats> cacheStats = cacheToStatsMap.get(cacheName);
        if (cacheStats == null)
        {
            throw new NoStatsForCache(cacheName);
        }
        long hits = cacheStats.get(OpType.GET_HIT).getCount();
        long misses = cacheStats.get(OpType.GET_MISS).getCount();
        return (double)hits / (hits+misses);
    }
    finally
    {
        readLock.unlock();
    }
}
 

@Override
public long numGets(String cacheName)
{
    ReadLock readLock = getReadLock(cacheName);
    readLock.lock();
    try
    {
        Map<OpType, OperationStats> cacheStats = cacheToStatsMap.get(cacheName);
        if (cacheStats == null)
        {
            throw new NoStatsForCache(cacheName);
        }
        long hits = cacheStats.get(OpType.GET_HIT).getCount();
        long misses = cacheStats.get(OpType.GET_MISS).getCount();
        return hits+misses;
    }
    finally
    {
        readLock.unlock();
    }
}
 

@Override
public Map<OpType, OperationStats> allStats(String cacheName)
{
    ReadLock readLock = getReadLock(cacheName);
    readLock.lock();
    try
    {
        Map<OpType, OperationStats> cacheStats = cacheToStatsMap.get(cacheName);
        if (cacheStats == null)
        {
            throw new NoStatsForCache(cacheName);
        }
        return new HashMap<>(cacheStats);
    }
    finally
    {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumIdle() {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return pool.getNumIdle();
    } finally {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumActive() {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return pool.getNumActive();
    } finally {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumIdle(final K key) {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return keyedPool.getNumIdle(key);
    } finally {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumActive(final K key) {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return keyedPool.getNumActive(key);
    } finally {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumIdle() {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return keyedPool.getNumIdle();
    } finally {
        readLock.unlock();
    }
}
 

/**
 * {@inheritDoc}
 */
@Override
public int getNumActive() {
    final ReadLock readLock = readWriteLock.readLock();
    readLock.lock();
    try {
        return keyedPool.getNumActive();
    } finally {
        readLock.unlock();
    }
}
 

/**
 * Simplest way to use the read mode
 * 
 * @return
 */
public String showContent() {
	ReadLock readLock = readWriteLock.readLock();
	readLock.lock();
	try {
		System.out.println("Reading state while holding a lock.");
		return myContent;
	} finally {
		readLock.unlock();
	}
}
 

/**
 * {@inheritDoc}
 * <p>
 * This store handles the {@link FileContentStore#SPOOF_PROTOCOL} so that underlying stores do not need
 * to implement anything <a href="https://issues.alfresco.com/jira/browse/ACE-4516">related to spoofing</a>.
 */
@Override
public ContentReader getReader(String contentUrl)
{
    // Handle the spoofed URL
    if (contentUrl.startsWith(FileContentStore.SPOOF_PROTOCOL))
    {
        return new SpoofedTextContentReader(contentUrl);
    }

    // Use pool of locks - which one is determined by a hash of the URL.
    // This will stop the content from being read/cached multiple times from the backing store
    // when it should only be read once - cached versions should be returned after that.
    ReadLock readLock = readWriteLock(contentUrl).readLock();
    readLock.lock();
    try
    {
        if (cache.contains(contentUrl))
        {
            return cache.getReader(contentUrl);
        }
    }
    catch(CacheMissException e)
    {
        // Fall through to cacheAndRead(url);
    }
    finally
    {
        readLock.unlock();
    }
    
    return cacheAndRead(contentUrl);
}
 

/**
 * 
 * @return
 * @author tanyaowu
 */
public int size() {
	ReadLock readLock = this.readLock();
	readLock.lock();
	try {
		List<T> list = this.getObj();
		return list.size();
	} finally {
		readLock.unlock();
	}
}
 

/**
 * 操作obj时，带上读锁
 * @param readLockHandler
 */
public void handle(ReadLockHandler<T> readLockHandler) {
	ReadLock readLock = lock.readLock();
	readLock.lock();
	try {
		readLockHandler.handler(obj);
	} catch (Throwable e) {
		log.error(e.getMessage(), e);
	} finally {
		readLock.unlock();
	}
}
 

/**
 * 
 * @param key
 * @return
 * @author tanyaowu
 */
public V get(K key) {
	ReadLock readLock = this.readLock();
	readLock.lock();
	try {
		Map<K, V> map = this.getObj();
		return map.get(key);
	} catch (Throwable e) {
		log.error(e.getMessage(), e);
	} finally {
		readLock.unlock();
	}
	return null;
}
 

/**
 * 
 * @return
 * @author tanyaowu
 */
public int size() {
	ReadLock readLock = this.readLock();
	readLock.lock();
	try {
		Map<K, V> map = this.getObj();
		return map.size();
	} finally {
		readLock.unlock();
	}
}
 

/**
 * 
 * @return 如果没值，则返回null，否则返回一个新map
 * @author tanyaowu
 */
public Map<K, V> copy() {
	ReadLock readLock = readLock();
	readLock.lock();
	try {
		if (this.getObj().size() > 0) {
			return new HashMap<>(getObj());
		}
		return null;
	} finally {
		readLock.unlock();
	}
}
 

/**
 * 
 * @return
 * @author tanyaowu
 */
public int size() {
	ReadLock readLock = this.readLock();
	readLock.lock();
	try {
		Set<T> set = this.getObj();
		return set.size();
	} finally {
		readLock.unlock();
	}
}
 

/**
	 * 运行write或者等待读锁<br>
	 * 1、能拿到写锁的线程会执行readWriteLockHandler.write()<br>
	 * 2、没拿到写锁的线程，会等待获取读锁，注：获取到读锁的线程，什么也不会执行<br>
	 * 3、当一段代码只允许被一个线程执行时，才用本函数，不要理解成同步等待了<br>
	 * <br>
	 * <strong>注意：对于一些需要判断null等其它条件才执行的操作，在write()方法中建议再检查一次，这个跟double check的原理是一样的</strong><br>
	 * @param key
	 * @param myLock 获取ReentrantReadWriteLock的锁，可以为null
	 * @param readWriteLockHandler 小心：该对象的write()方法并不一定会被执行
	 * @param readWaitTimeInSecond 没拿到写锁的线程，等读锁的时间，单位：秒
	 * @return
	 * @throws Exception
	 * @author tanyaowu
	 */
	public static void runWriteOrWaitRead(String key, Object myLock, ReadWriteLockHandler readWriteLockHandler, Long readWaitTimeInSecond) throws Exception {
		ReentrantReadWriteLock rwLock = getReentrantReadWriteLock(key, myLock);
//		ReadWriteRet ret = new ReadWriteRet();
		WriteLock writeLock = rwLock.writeLock();
		boolean tryWrite = writeLock.tryLock();
		if (tryWrite) {
			try {
				readWriteLockHandler.write();
//				ret.writeRet = writeRet;
			} finally {
//				ret.isWriteRunned = true;
				writeLock.unlock();
			}
		} else {
			ReadLock readLock = rwLock.readLock();
			boolean tryRead = false;
			try {
				tryRead = readLock.tryLock(readWaitTimeInSecond, TimeUnit.SECONDS);
				if (tryRead) {
//					try {
//						readWriteLockHandler.read();
//						ret.readRet = readRet;
//					} finally {
//						ret.isReadRunned = true;
						readLock.unlock();
//					}
				}
			} catch (InterruptedException e) {
				log.error(e.toString(), e);
			}
		}
//		return ret;
	}
 

@Override
public void run() {

	while (true) {
		try {
			Thread.sleep(10 * 1000);
		} catch (InterruptedException e1) {
			log.error(e1.toString(), e1);
		}

		SetWithLock<ChannelContext> setWithLock = serverTioConfig.connections;
		Set<ChannelContext> set = null;
		ReadLock readLock = setWithLock.readLock();
		readLock.lock();
		try {
			long now = SystemTimer.currTime;
			set = setWithLock.getObj();
			for (ChannelContext channelContext : set) {
				long interval = (now - channelContext.stat.timeFirstConnected);
				if (interval > 5000) {
					Tio.remove(channelContext, "已经连上来有" + interval + "ms了，该断开啦");
				}
			}
		} catch (java.lang.Throwable e) {
			log.error("", e);
		} finally {
			readLock.unlock();
		}
	}
}
 

/** Gets the value of the counter associated with a given key.
 *
 * @param array a byte array.
 * @param offset the first valid byte in {@code array}.
 * @param length the number of valid elements in {@code array}.
 * @return the current value of the counter associated with the specified key.
 */
public int get(final byte[] array, final int offset, final int length) {
	final long hash = MurmurHash3.hash(array, offset, length);
	final ReadLock readLock = lock[(int)(hash >>> shift)].readLock();
	try {
		readLock.lock();
		return stripe[(int)(hash >>> shift)].get(array, offset, length, hash);
	}
	finally {
		readLock.unlock();
	}
}
 

public IAutoCloseable lockForReading()
{
	// assume _lock is not null
	final ReadLock readLock = _lock.readLock();
	logger.debug("Acquiring read lock for {}: {}", this, readLock);
	readLock.lock();
	logger.debug("Acquired read lock for {}: {}", this, readLock);

	return () -> {
		readLock.unlock();
		logger.debug("Released read lock for {}: {}", this, readLock);
	};
}
 

IAutoCloseable lockForReading()
{
	final ReadLock readLock = readwriteLock.readLock();
	logger.debug("Acquiring read lock for {}: {}", this, readLock);
	readLock.lock();
	logger.debug("Acquired read lock for {}: {}", this, readLock);

	return () -> {
		readLock.unlock();
		logger.debug("Released read lock for {}: {}", this, readLock);
	};
}
 

IAutoCloseable lockForReading()
{
	// assume _lock is not null
	final ReadLock readLock = _lock.readLock();
	logger.debug("Acquiring read lock for {}: {}", this, readLock);
	readLock.lock();
	logger.debug("Acquired read lock for {}: {}", this, readLock);

	return () -> {
		readLock.unlock();
		logger.debug("Released read lock for {}: {}", this, readLock);
	};
}
 

public IAutoCloseable lockForReading()
{
	final ReadLock readLock = readwriteLock.readLock();
	logger.debug("Acquiring read lock for {}: {}", this, readLock);
	readLock.lock();
	logger.debug("Acquired read lock for {}: {}", this, readLock);

	return () -> {
		readLock.unlock();
		logger.debug("Released read lock for {}: {}", this, readLock);
	};
}
 

@NoWarning("UL_UNRELEASED_LOCK")
public void doTestA() {
    ReadLock readLock = rwLock.readLock();
    readLock.lock();

    System.out.println("testing");

}
 

@ExpectWarning("UL_UNRELEASED_LOCK_EXCEPTION_PATH")
public void doTest2A() {
    ReadLock readLock = rwLock.readLock();
    readLock.lock();

    System.out.println("testing");
    readLock.unlock();

}
 

@ExpectWarning("UL_UNRELEASED_LOCK")
public void doTest2A(boolean b) {
    ReadLock readLock = rwLock.readLock();
    readLock.lock();

    if (b)
        return;
    System.out.println("testing");
    readLock.unlock();

}
 

@ExpectWarning("UL_UNRELEASED_LOCK_EXCEPTION_PATH")
public void doTest2A(OutputStream o) throws IOException {
    ReadLock readLock = rwLock.readLock();
    readLock.lock();

    o.write(0);
    readLock.unlock();

}