Java Code Examples for java.util.concurrent.locks.StampedLock#writeLock()

/**
 * Update configuration of group in route table.
 *
 * @param groupId raft group id
 * @param conf    configuration to update
 * @return true on success
 */
public boolean updateConfiguration(final String groupId, final Configuration conf) {
    Requires.requireTrue(!StringUtils.isBlank(groupId), "Blank group id");
    Requires.requireNonNull(conf, "Null configuration");

    final GroupConf gc = getOrCreateGroupConf(groupId);
    final StampedLock stampedLock = gc.stampedLock;
    final long stamp = stampedLock.writeLock();
    try {
        gc.conf = conf;
        if (gc.leader != null && !gc.conf.contains(gc.leader)) {
            gc.leader = null;
        }
    } finally {
        stampedLock.unlockWrite(stamp);
    }
    return true;
}
 

/**
 * Update leader info.
 *
 * @param groupId raft group id
 * @param leader  peer of leader
 * @return true on success
 */
public boolean updateLeader(final String groupId, final PeerId leader) {
    Requires.requireTrue(!StringUtils.isBlank(groupId), "Blank group id");

    if (leader != null) {
        // If leader presents, it should not be empty.
        Requires.requireTrue(!leader.isEmpty(), "Empty leader");
    }

    final GroupConf gc = getOrCreateGroupConf(groupId);
    final StampedLock stampedLock = gc.stampedLock;
    final long stamp = stampedLock.writeLock();
    try {
        gc.leader = leader;
    } finally {
        stampedLock.unlockWrite(stamp);
    }
    return true;
}
 

/**
 * interruptible operations throw InterruptedException when write locked and interrupted
 */
public void testInterruptibleOperationsThrowInterruptedExceptionWriteLockedInterrupted() {
    final StampedLock lock = new StampedLock();
    long s = lock.writeLock();

    Action[] interruptibleLockBlockingActions = {
        () -> lock.writeLockInterruptibly(),
        () -> lock.tryWriteLock(Long.MAX_VALUE, DAYS),
        () -> lock.readLockInterruptibly(),
        () -> lock.tryReadLock(Long.MAX_VALUE, DAYS),
        () -> lock.asWriteLock().lockInterruptibly(),
        () -> lock.asWriteLock().tryLock(Long.MAX_VALUE, DAYS),
        () -> lock.asReadLock().lockInterruptibly(),
        () -> lock.asReadLock().tryLock(Long.MAX_VALUE, DAYS),
    };
    shuffle(interruptibleLockBlockingActions);

    assertThrowInterruptedExceptionWhenInterrupted(interruptibleLockBlockingActions);
}
 

/**
 * readLock() succeed only after a writing thread unlocks
 */
public void testReadAfterWriteLock() {
    final StampedLock lock = new StampedLock();
    final CountDownLatch threadsStarted = new CountDownLatch(2);
    final long s = lock.writeLock();
    final Runnable acquireReleaseReadLock = new CheckedRunnable() {
        public void realRun() {
            threadsStarted.countDown();
            long rs = lock.readLock();
            assertTrue(lock.isReadLocked());
            assertFalse(lock.isWriteLocked());
            lock.unlockRead(rs);
        }};
    Thread t1 = newStartedThread(acquireReleaseReadLock);
    Thread t2 = newStartedThread(acquireReleaseReadLock);

    await(threadsStarted);
    waitForThreadToEnterWaitState(t1);
    waitForThreadToEnterWaitState(t2);
    assertTrue(lock.isWriteLocked());
    assertFalse(lock.isReadLocked());
    releaseWriteLock(lock, s);
    awaitTermination(t1);
    awaitTermination(t2);
    assertUnlocked(lock);
}
 

public void addOrUpdateRegion(final Region region) {
    Requires.requireNonNull(region, "region");
    Requires.requireNonNull(region.getRegionEpoch(), "regionEpoch");
    final long regionId = region.getId();
    final byte[] startKey = BytesUtil.nullToEmpty(region.getStartKey());
    final StampedLock stampedLock = this.stampedLock;
    final long stamp = stampedLock.writeLock();
    try {
        this.regionTable.put(regionId, region.copy());
        this.rangeTable.put(startKey, regionId);
    } finally {
        stampedLock.unlockWrite(stamp);
    }
}
 

public void splitRegion(final long leftId, final Region right) {
    Requires.requireNonNull(right, "right");
    Requires.requireNonNull(right.getRegionEpoch(), "right.regionEpoch");
    final StampedLock stampedLock = this.stampedLock;
    final long stamp = stampedLock.writeLock();
    try {
        final Region left = this.regionTable.get(leftId);
        Requires.requireNonNull(left, "left");
        final byte[] leftStartKey = BytesUtil.nullToEmpty(left.getStartKey());
        final byte[] leftEndKey = left.getEndKey();
        final long rightId = right.getId();
        final byte[] rightStartKey = right.getStartKey();
        final byte[] rightEndKey = right.getEndKey();
        Requires.requireNonNull(rightStartKey, "rightStartKey");
        Requires.requireTrue(BytesUtil.compare(leftStartKey, rightStartKey) < 0,
            "leftStartKey must < rightStartKey");
        if (leftEndKey == null || rightEndKey == null) {
            Requires.requireTrue(leftEndKey == rightEndKey, "leftEndKey must == rightEndKey");
        } else {
            Requires.requireTrue(BytesUtil.compare(leftEndKey, rightEndKey) == 0, "leftEndKey must == rightEndKey");
            Requires.requireTrue(BytesUtil.compare(rightStartKey, rightEndKey) < 0,
                "rightStartKey must < rightEndKey");
        }
        final RegionEpoch leftEpoch = left.getRegionEpoch();
        leftEpoch.setVersion(leftEpoch.getVersion() + 1);
        left.setEndKey(rightStartKey);
        this.regionTable.put(rightId, right.copy());
        this.rangeTable.put(rightStartKey, rightId);
    } finally {
        stampedLock.unlockWrite(stamp);
    }
}
 

public boolean removeRegion(final long regionId) {
    final StampedLock stampedLock = this.stampedLock;
    final long stamp = stampedLock.writeLock();
    try {
        final Region region = this.regionTable.remove(regionId);
        if (region != null) {
            final byte[] startKey = BytesUtil.nullToEmpty(region.getStartKey());
            return this.rangeTable.remove(startKey) != null;
        }
    } finally {
        stampedLock.unlockWrite(stamp);
    }
    return false;
}
 

/**
 * tryWriteLock fails if locked
 */
public void testTryWriteLockWhenLocked() {
    final StampedLock lock = new StampedLock();
    long s = lock.writeLock();
    Thread t = newStartedThread(new CheckedRunnable() {
        public void realRun() {
            assertEquals(0L, lock.tryWriteLock());
        }});

    assertEquals(0L, lock.tryWriteLock());
    awaitTermination(t);
    releaseWriteLock(lock, s);
}
 

/**
 * tryReadLock fails if write-locked
 */
public void testTryReadLockWhenLocked() {
    final StampedLock lock = new StampedLock();
    long s = lock.writeLock();
    Thread t = newStartedThread(new CheckedRunnable() {
        public void realRun() {
            assertEquals(0L, lock.tryReadLock());
        }});

    assertEquals(0L, lock.tryReadLock());
    awaitTermination(t);
    releaseWriteLock(lock, s);
}
 

/**
 * A serialized lock deserializes as unlocked
 */
public void testSerialization() {
    StampedLock lock = new StampedLock();
    lock.writeLock();
    StampedLock clone = serialClone(lock);
    assertTrue(lock.isWriteLocked());
    assertFalse(clone.isWriteLocked());
    long s = clone.writeLock();
    assertTrue(clone.isWriteLocked());
    clone.unlockWrite(s);
    assertFalse(clone.isWriteLocked());
}
 

/**
 * toString indicates current lock state
 */
public void testToString() {
    StampedLock lock = new StampedLock();
    assertTrue(lock.toString().contains("Unlocked"));
    long s = lock.writeLock();
    assertTrue(lock.toString().contains("Write-locked"));
    lock.unlockWrite(s);
    s = lock.readLock();
    assertTrue(lock.toString().contains("Read-locks"));
}
 

@Override
protected void process(int chainId, ChainContext context, NulsLogger commonLog) {
    StampedLock lock = context.getLock();
    long stamp = lock.tryOptimisticRead();
    try {
        for (; ; stamp = lock.writeLock()) {
            if (stamp == 0L) {
                continue;
            }
            // possibly racy reads
            SortedSet<Chain> forkChains = BlockChainManager.getForkChains(chainId);
            if (!lock.validate(stamp)) {
                continue;
            }
            if (forkChains.isEmpty()) {
                break;
            }
            context.printChains();
            //遍历当前分叉链,与主链进行比对,找出最大高度差,与默认参数chainSwtichThreshold对比,确定要切换的分叉链
            Chain masterChain = BlockChainManager.getMasterChain(chainId);
            ChainParameters parameters = context.getParameters();
            int chainSwtichThreshold = parameters.getChainSwtichThreshold();
            Chain switchChain = new Chain();
            int maxHeightDifference = 0;
            for (Chain forkChain : forkChains) {
                int temp = (int) (forkChain.getEndHeight() - masterChain.getEndHeight());
                if (temp > maxHeightDifference) {
                    maxHeightDifference = temp;
                    switchChain = forkChain;
                }
            }
            commonLog.debug("chainId-" + chainId + ", maxHeightDifference:" + maxHeightDifference + ", chainSwtichThreshold:" + chainSwtichThreshold);
            //高度差不够
            if (maxHeightDifference < chainSwtichThreshold) {
                break;
            }
            stamp = lock.tryConvertToWriteLock(stamp);
            if (stamp == 0L) {
                continue;
            }
            // exclusive access
            //进行切换,切换前变更模块运行状态
            context.setStatus(StatusEnum.SWITCHING);
            ConsensusCall.notice(chainId, MODULE_WAITING);
            TransactionCall.notice(chainId, MODULE_WAITING);
            if (BlockChainManager.switchChain(chainId, masterChain, switchChain)) {
                commonLog.info("chainId-" + chainId + ", switchChain success");
            } else {
                commonLog.info("chainId-" + chainId + ", switchChain fail, auto rollback success");
            }
            context.printChains();
            ConsensusCall.notice(chainId, MODULE_WORKING);
            TransactionCall.notice(chainId, MODULE_WORKING);
            break;
        }
    } finally {
        context.setStatus(StatusEnum.RUNNING);
        if (StampedLock.isWriteLockStamp(stamp)) {
            lock.unlockWrite(stamp);
        }
    }
}
 

@Override
protected void process(int chainId, ChainContext context, NulsLogger commonLog) {
    ChainParameters parameters = context.getParameters();
    int orphanChainMaxAge = parameters.getOrphanChainMaxAge();

    StampedLock lock = context.getLock();
    long stamp = lock.tryOptimisticRead();
    try {
        for (; ; stamp = lock.writeLock()) {
            if (stamp == 0L) {
                continue;
            }
            // possibly racy reads
            SortedSet<Chain> orphanChains = BlockChainManager.getOrphanChains(chainId);
            if (!lock.validate(stamp)) {
                continue;
            }
            if (orphanChains.isEmpty()) {
                break;
            }
            stamp = lock.tryConvertToWriteLock(stamp);
            if (stamp == 0L) {
                continue;
            }
            // exclusive access
            List<Node> availableNodes = NetworkCall.getAvailableNodes(chainId);
            //维护现有孤儿链,尝试在链首增加区块
            context.setStatus(UPDATE_ORPHAN_CHAINS);
            long l = System.nanoTime();
            for (Chain orphanChain : orphanChains) {
                maintainOrphanChain(chainId, orphanChain, availableNodes, orphanChainMaxAge);
                //孤儿链维护时间超过十秒，就退出
                if (System.nanoTime() - l > 10000000000L) {
                    break;
                }
            }
            break;
        }
    } finally {
        context.setStatus(RUNNING);
        if (StampedLock.isWriteLockStamp(stamp)) {
            lock.unlockWrite(stamp);
        }
    }
}
 

/**
 * 清理分叉链
 *
 * @param chainId
 * @param heightRange
 * @param context
 */
private void forkChainsCleaner(int chainId, int heightRange, ChainContext context) {
    StampedLock lock = context.getLock();
    long stamp = lock.tryOptimisticRead();
    NulsLogger logger = context.getLogger();
    try {
        for (; ; stamp = lock.writeLock()) {
            if (stamp == 0L) {
                continue;
            }
            // possibly racy reads
            //1.清理链起始高度位于主链最新高度增减30(可配置)范围外的分叉链
            SortedSet<Chain> forkChains = BlockChainManager.getForkChains(chainId);
            if (!lock.validate(stamp)) {
                continue;
            }
            if (forkChains.isEmpty()) {
                break;
            }
            stamp = lock.tryConvertToWriteLock(stamp);
            if (stamp == 0L) {
                continue;
            }
            // exclusive access
            Chain masterChain = BlockChainManager.getMasterChain(chainId);
            long latestHeight = masterChain.getEndHeight();
            SortedSet<Chain> deleteSet = new TreeSet<>(Chain.COMPARATOR);
            //1.标记
            for (Chain forkChain : forkChains) {
                if (latestHeight - forkChain.getStartHeight() > heightRange || masterChain.getHashList().contains(forkChain.getEndHash())) {
                    //清理orphanChain,并递归清理orphanChain的所有子链
                    deleteSet.add(forkChain);
                }
            }
            //2.清理
            for (Chain chain : deleteSet) {
                BlockChainManager.deleteForkChain(chainId, chain, true);
                logger.info("remove fork chain, chain:" + chain);
            }
            break;
        }
    } finally {
        if (StampedLock.isWriteLockStamp(stamp)) {
            lock.unlockWrite(stamp);
        }
    }
}
 

/**
 * 清理孤儿链
 * @param chainId
 * @param heightRange
 * @param context
 * @param orphanChainMaxAge
 */
private void orphanChainsCleaner(int chainId, int heightRange, ChainContext context, int orphanChainMaxAge) {
    StampedLock lock = context.getLock();
    long stamp = lock.tryOptimisticRead();
    NulsLogger logger = context.getLogger();
    try {
        for (; ; stamp = lock.writeLock()) {
            if (stamp == 0L) {
                continue;
            }
            // possibly racy reads
            //1.清理链起始高度位于主链最新高度增减30(可配置)范围外的孤儿链
            SortedSet<Chain> orphanChains = BlockChainManager.getOrphanChains(chainId);
            if (!lock.validate(stamp)) {
                continue;
            }
            if (orphanChains.isEmpty()) {
                break;
            }
            stamp = lock.tryConvertToWriteLock(stamp);
            if (stamp == 0L) {
                continue;
            }
            // exclusive access
            Chain masterChain = BlockChainManager.getMasterChain(chainId);
            long latestHeight = masterChain.getEndHeight();
            SortedSet<Chain> deleteSet = new TreeSet<>(Chain.COMPARATOR);
            //1.标记
            for (Chain orphanChain : orphanChains) {
                if (Math.abs(orphanChain.getStartHeight() - latestHeight) > heightRange || orphanChain.getAge().get() > orphanChainMaxAge) {
                    //清理orphanChain,并递归清理orphanChain的所有子链
                    deleteSet.add(orphanChain);
                }
            }
            //2.清理
            for (Chain chain : deleteSet) {
                BlockChainManager.deleteOrphanChain(chainId, chain);
                logger.info("remove orphan chain, chain:" + chain);
            }
            break;
        }
    } finally {
        if (StampedLock.isWriteLockStamp(stamp)) {
            lock.unlockWrite(stamp);
        }
    }
}
 

LockID acquireWriteLockForKey(RawString key, String clientId) {
    StampedLock lock = makeLockForKey(key);
    LockID result = new LockID(lock.writeLock());
    return result;
}