Synchronous Queue example to execute commands

private BlockingQueue workQueue = new LinkedBlockingQueue();
private Map commandQueueMap = new ConcurrentHashMap(); 
public SynchronousQueue addCommand(Command command) {
    SynchronousQueue queue = new SynchronousQueue();
    commandQueueMap.put(command, queue);
    return queue;
public Object call() throws Exception {
    try {

  Command command = workQueue.take();

  Result result = command.execute();

  SynchronousQueue queue = commandQueueMap.get(command);


  return null;
    } catch (InterruptedException e) {

  throw new WorkException(e);

Now the consumer can safely poll with timeout on its request to have its Command executed.

Command command;
SynchronousQueue queue = commandRunner.addCommand(command);
Result result = queue.poll(2, TimeUnit.MINUTES);
if (result == null) {
	throw new CommandTooLongException(command);
} else {
	return result;

Related Article:

Reference: Java Concurrency Part 5 – Blocking Queues from our JCG partners at the Carfey Software blog

Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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