Java Code Examples for java.util.concurrent.BlockingQueue#drainTo()

private List<IncomingMessageEnvelope> getNextMessages(
    SystemStreamPartition ssp, long timeoutMillis) throws InterruptedException {
  if (lastException != null) {
    throw new RuntimeException(lastException);
  }

  final List<IncomingMessageEnvelope> envelopes = new ArrayList<>();
  final BlockingQueue<IncomingMessageEnvelope> queue = queues.get(ssp);
  final IncomingMessageEnvelope envelope = queue.poll(timeoutMillis, TimeUnit.MILLISECONDS);

  if (envelope != null) {
    envelopes.add(envelope);
    queue.drainTo(envelopes);
  }

  available.release(envelopes.size());

  if (lastException != null) {
    throw new RuntimeException(lastException);
  }

  return envelopes;
}
 

/**
 * Handle bulk item deletion.
 *
 * @param itemDeletionQueue the queue that's used for deleting items
 */
public void performItemDeletion(BlockingQueue<Integer> itemDeletionQueue) {
    try {
        if (itemDeletionQueue.isEmpty()) {
            return;
        }

        List<Integer> itemList = new ArrayList<>();
        itemDeletionQueue.drainTo(itemList);

        if (itemList.size() > 0) {
            ItemDao.deleteItems(itemList);
        }
    } catch (Exception ex) {
        Log.getErrorLogger().error("Error when attempting to save items: ", ex);
    }
}
 

void testDelayQueue(final BlockingQueue q) throws Throwable {
    System.err.println(q.getClass().getSimpleName());
    for (int i = 0; i < CAPACITY; i++)
        q.add(new PDelay(i));
    ArrayBlockingQueue q2 = new ArrayBlockingQueue(SMALL);
    try {
        q.drainTo(q2, SMALL + 3);
        fail("should throw");
    } catch (IllegalStateException success) {
        equal(SMALL, q2.size());
        equal(new PDelay(0), q2.poll());
        equal(new PDelay(1), q2.poll());
        check(q2.isEmpty());
        for (int i = SMALL; i < CAPACITY; i++)
            equal(new PDelay(i), q.poll());
        equal(0, q.size());
    }
}
 

@Override
protected <C extends Coalescable> void coalesceInternal(BlockingQueue<C> input, List<C> out,  int maxItems) throws InterruptedException
{
    if (input.drainTo(out, maxItems) == 0)
    {
        out.add(input.take());
    }

    long average = notifyOfSample(out.get(0).timestampNanos());

    debugGap(average);

    maybeSleep(out.size(), average, maxCoalesceWindow, parker);

    input.drainTo(out, maxItems - out.size());
    for (int ii = 1; ii < out.size(); ii++)
        notifyOfSample(out.get(ii).timestampNanos());
}
 

private List<Update<T>> getUpdateBatch(
        final BlockingQueue<Update<T>> updatesQueue) throws InterruptedException {
    Update<T> update = updatesQueue.poll(1000, TimeUnit.MILLISECONDS);
    if (update != null) {
        // We have at least one pending update, check if there's more!
        List<Update<T>> updatesBatch = new ArrayList<>();
        updatesBatch.add(update);
        if (updatesQueue.peek() != null) {
            logger.debug("Subscription received update, queue not empty, draining ...");
            updatesQueue.drainTo(updatesBatch);
        } else {
            logger.debug("Subscription received single update");
        }
        return updatesBatch;
    } else {
        // Nothing pending, nothing to see here
        logger.trace("No update (yet)");
        return null;
    }
}
 

/**
 * Drains the queue as {@link BlockingQueue#drainTo(Collection, int)}, but if the requested
 * {@code numElements} elements are not available, it will wait for them up to the specified
 * timeout.
 *
 * @param q the blocking queue to be drained
 * @param buffer where to add the transferred elements
 * @param numElements the number of elements to be waited for
 * @param timeout how long to wait before giving up, in units of {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
 * @return the number of elements transferred
 * @throws InterruptedException if interrupted while waiting
 */

@Beta
@CanIgnoreReturnValue
public static <E> int drain(
  BlockingQueue<E> q,
  Collection<? super E> buffer,
  int numElements,
  long timeout,
  TimeUnit unit)
    throws InterruptedException {
  Preconditions.checkNotNull(buffer);
  /*
   * This code performs one System.nanoTime() more than necessary, and in return, the time to
   * execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
   * the timeout arbitrarily inaccurate, given a queue that is slow to drain).
   */
  long deadline = System.nanoTime() + unit.toNanos(timeout);
  int added = 0;
  while (added < numElements) {
    // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
    // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
    added += q.drainTo(buffer, numElements - added);
    if (added < numElements) { // not enough elements immediately available; will have to poll
      E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
      if (e == null) {
        break; // we already waited enough, and there are no more elements in sight
      }
      buffer.add(e);
      added++;
    }
  }
  return added;
}
 

@Override
public Collection<Message> getAllOfflineMessage(String clientId) {
    BlockingQueue<Message> queue = offlineTable.get(clientId);
    Collection<Message> allMessages = new ArrayList<>();
    queue.drainTo(allMessages);
    return allMessages;
}
 

@Override
public Collection<Message> getAllOfflineMessage(String clientId) {
    BlockingQueue<Message> queue = offlineTable.get(clientId);
    Collection<Message> allMessages = new ArrayList<>();
    int rs = queue.drainTo(allMessages);
    return allMessages;
}
 

@Override
public void onSync(final int partitionIndex) {
    final BlockingQueue<ResourceClaim> claimQueue = claimsAwaitingDestruction.get(Integer.valueOf(partitionIndex));
    if (claimQueue == null) {
        return;
    }

    final Set<ResourceClaim> claimsToDestroy = new HashSet<>();
    claimQueue.drainTo(claimsToDestroy);

    for (final ResourceClaim claim : claimsToDestroy) {
        markDestructable(claim);
    }
}
 

/**
 * drainTo defers to each sub-queue. Note that draining from a FairCallQueue
 * to another FairCallQueue will likely fail, since the incoming calls
 * may be scheduled differently in the new FairCallQueue. Nonetheless this
 * method is provided for completeness.
 */
@Override
public int drainTo(Collection<? super E> c, int maxElements) {
  int sum = 0;
  for (BlockingQueue<E> q : this.queues) {
    sum += q.drainTo(c, maxElements);
  }
  return sum;
}
 

public void stopStreaming() {
    if (resultsQueue != null) {
        client.stopStreaming(partitionsToStream()).await();
        BlockingQueue<ByteBuf> queue = resultsQueue;
        resultsQueue = null;
        List<ByteBuf> drained = new ArrayList<ByteBuf>();
        queue.drainTo(drained);
        for (ByteBuf byteBuf : drained) {
            byteBuf.release();
        }
        client.disconnect();
    }
}
 

/**
 * Drains the queue as {@link BlockingQueue#drainTo(Collection, int)}, but if the requested
 * {@code numElements} elements are not available, it will wait for them up to the specified
 * timeout.
 *
 * @param q the blocking queue to be drained
 * @param buffer where to add the transferred elements
 * @param numElements the number of elements to be waited for
 * @param timeout how long to wait before giving up, in units of {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
 * @return the number of elements transferred
 * @throws InterruptedException if interrupted while waiting
 */
@Beta
@CanIgnoreReturnValue
public static <E> int drain(
    BlockingQueue<E> q,
    Collection<? super E> buffer,
    int numElements,
    long timeout,
    TimeUnit unit)
    throws InterruptedException {
  Preconditions.checkNotNull(buffer);
  /*
   * This code performs one System.nanoTime() more than necessary, and in return, the time to
   * execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
   * the timeout arbitrarily inaccurate, given a queue that is slow to drain).
   */
  long deadline = System.nanoTime() + unit.toNanos(timeout);
  int added = 0;
  while (added < numElements) {
    // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
    // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
    added += q.drainTo(buffer, numElements - added);
    if (added < numElements) { // not enough elements immediately available; will have to poll
      E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
      if (e == null) {
        break; // we already waited enough, and there are no more elements in sight
      }
      buffer.add(e);
      added++;
    }
  }
  return added;
}
 

/**
 * Drains the queue as {@link BlockingQueue#drainTo(Collection, int)}, but if the requested
 * {@code numElements} elements are not available, it will wait for them up to the specified
 * timeout.
 *
 * @param q the blocking queue to be drained
 * @param buffer where to add the transferred elements
 * @param numElements the number of elements to be waited for
 * @param timeout how long to wait before giving up, in units of {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
 * @return the number of elements transferred
 * @throws InterruptedException if interrupted while waiting
 */

@Beta
@CanIgnoreReturnValue
public static <E> int drain(
  BlockingQueue<E> q,
  Collection<? super E> buffer,
  int numElements,
  long timeout,
  TimeUnit unit)
    throws InterruptedException {
  Preconditions.checkNotNull(buffer);
  /*
   * This code performs one System.nanoTime() more than necessary, and in return, the time to
   * execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
   * the timeout arbitrarily inaccurate, given a queue that is slow to drain).
   */
  long deadline = System.nanoTime() + unit.toNanos(timeout);
  int added = 0;
  while (added < numElements) {
    // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
    // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
    added += q.drainTo(buffer, numElements - added);
    if (added < numElements) { // not enough elements immediately available; will have to poll
      E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
      if (e == null) {
        break; // we already waited enough, and there are no more elements in sight
      }
      buffer.add(e);
      added++;
    }
  }
  return added;
}
 

/**
 * drainTo(this, n) throws IllegalArgumentException
 */
public void testDrainToSelfN() {
    final BlockingQueue q = emptyCollection();
    try {
        q.drainTo(q, 0);
        shouldThrow();
    } catch (IllegalArgumentException success) {}
}
 

@Override
public int drainTo(Collection<? super E> c) {
  int sum = 0;
  for (BlockingQueue<E> q : this.queues) {
    sum += q.drainTo(c);
  }
  return sum;
}
 

public List<Runnable> drainExceedQueue() {
    BlockingQueue<Runnable> q = mExceedQueue;
    ArrayList<Runnable> taskList = new ArrayList<>();
    q.drainTo(taskList);
    if (!q.isEmpty()) {
        for (Runnable r : q.toArray(new Runnable[0])) {
            if (q.remove(r))
                taskList.add(r);
        }
    }
    return taskList;
}
 

/**
 * Drains delayed responses queue and returns responses in an array
 *
 * @return and array of DelayedConfigResponse objects
 */
List<DelayedConfigResponse> drainQueue(ApplicationId app) {
    ArrayList<DelayedConfigResponse> ret = new ArrayList<>();
    
    if (delayedResponses.containsKey(app)) {
        BlockingQueue<DelayedConfigResponse> queue = delayedResponses.get(app);
        queue.drainTo(ret);
    }
    metrics.remove(app);
    return ret;
}
 

@Override
protected void releaseAcceptedMessages() {

    for (Map.Entry<BSBundle, BlockingQueue<IChunkMessage<IBindingSet>>> e : operatorQueues
            .entrySet()) {

        final BlockingQueue<IChunkMessage<IBindingSet>> queue = e.getValue();

        if (queue.isEmpty())
            continue;
        
        final LinkedList<IChunkMessage<IBindingSet>> c = new LinkedList<IChunkMessage<IBindingSet>>();

        queue.drainTo(c);

        for (IChunkMessage<IBindingSet> msg : c) {

            msg.release();
            
        }
        
    }
 
}
 

public Stream<TweetHandler> stream() {
        String myKey = "sl2WbCf4UnIr08xvHVitHJ99r";
        String mySecret = "PE6yauvXjKLuvoQNXZAJo5C8N5U5piSFb3udwkoI76paK6KyqI";
        String myToken = "1098376471-p6iWfxCLtyMvMutTb010w1D1xZ3UyJhcC2kkBjN";
        String myAccess = "2o1uGcp4b2bFynOfu2cA1uz63n5aruV0RwNsUjRpjDBZS";

        out.println("Creating Twitter Stream");
        BlockingQueue<String> statusQueue = new LinkedBlockingQueue<>(1000);
        StatusesFilterEndpoint endpoint = new StatusesFilterEndpoint();
        endpoint.trackTerms(Lists.newArrayList("twitterapi", this.topic));
        endpoint.stallWarnings(false);
        Authentication twitterAuth = new OAuth1(myKey, mySecret, myToken, myAccess);

        BasicClient twitterClient = new ClientBuilder()
                .name("Twitter client")
                .hosts(Constants.STREAM_HOST)
                .endpoint(endpoint)
                .authentication(twitterAuth)
                .processor(new StringDelimitedProcessor(statusQueue))
                .build();

        twitterClient.connect();

        List<TweetHandler> list = new ArrayList();
        List<String> twitterList = new ArrayList();

        statusQueue.drainTo(twitterList);
        for(int i=0; i<numberOfTweets; i++) {
            String message;
            try {
                message = statusQueue.take();
                list.add(new TweetHandler(message));
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }

//        for (int msgRead = 0; msgRead < this.numberOfTweets; msgRead++) {
//            try {
//                if (twitterClient.isDone()) {
//                  //  out.println(twitterClient.getExitEvent().getMessage());
//                    break;
//                }
//
//                String msg = statusQueue.poll(10, TimeUnit.SECONDS);
//                if (msg == null) {
//                    out.println("Waited 10 seconds - no message received");
//                } else {
//                    list.add(new TweetHandler(msg));
//                    out.println("Added message: " + msg.length());
//                }
//            } catch (InterruptedException ex) {
//                ex.printStackTrace();
//            }
//        }
        twitterClient.stop();
        out.printf("%d messages processed!\n", twitterClient.getStatsTracker().getNumMessages());

        return list.stream();
    }
 

/**
 * Drains the queue as {@linkplain #drain(BlockingQueue, Collection, int, long, TimeUnit)},
 * but with a different behavior in case it is interrupted while waiting. In that case, the
 * operation will continue as usual, and in the end the thread's interruption status will be set
 * (no {@code InterruptedException} is thrown).
 *
 * @param q the blocking queue to be drained
 * @param buffer where to add the transferred elements
 * @param numElements the number of elements to be waited for
 * @param timeout how long to wait before giving up, in units of {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
 * @return the number of elements transferred
 */

@Beta
@CanIgnoreReturnValue
public static <E> int drainUninterruptibly(
  BlockingQueue<E> q,
  Collection<? super E> buffer,
  int numElements,
  long timeout,
  TimeUnit unit) {
  Preconditions.checkNotNull(buffer);
  long deadline = System.nanoTime() + unit.toNanos(timeout);
  int added = 0;
  boolean interrupted = false;
  try {
    while (added < numElements) {
      // we could rely solely on #poll, but #drainTo might be more efficient when there are
      // multiple elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
      added += q.drainTo(buffer, numElements - added);
      if (added < numElements) { // not enough elements immediately available; will have to poll
        E e; // written exactly once, by a successful (uninterrupted) invocation of #poll
        while (true) {
          try {
            e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
            break;
          } catch (InterruptedException ex) {
            interrupted = true; // note interruption and retry
          }
        }
        if (e == null) {
          break; // we already waited enough, and there are no more elements in sight
        }
        buffer.add(e);
        added++;
      }
    }
  } finally {
    if (interrupted) {
      Thread.currentThread().interrupt();
    }
  }
  return added;
}