Java - Waiting for a max time or an event (async callback), which ever comes first

Question

So the title is explanatory, I want to wait on a thread for a max time say 1 sec, now within this 1 sec if the other thread receives a response then its fine, otherwise after 1 sec whether or not a response is recieved it should stop waiting and continue with its work, later I can wait for another 2 seconds to see if the response has arrived

Main Class:

atiReq.Now(); //asynchronous method returns immediatly
                firstATIState = atiReq.getState(1000); // Wait for a max of 1000 ms to get the response
            }
            handleIDP();
            if (isMobSub && firstATIState == null) {
                //If ati response was not recived previously wait for another maximum 2000 ms now
                firstATIState = atiReq.getState(2000);
            }

AtiRequest Class:

 /**
     * Does an ATI Request asynchrounously
     */
    public void Now() {
        new Thread() {
            public void run() {
                atiReq.run();
                synchronized (atiReq) {
                    try {
                        atiReq.wait(3000);
                        rawResponse = atiReq.ReturnXML;
                        logger.info("[" + refID + "] ATI Response recieved: " + rawResponse);
                        atiResponseRecieved = true;
                        atiReq.notify();
                    } catch (InterruptedException ex) {
                        logger.error("Error waiting on atiReq", ex);
                    }
                }
            }
        }.start();
    }

    public String GetRawResponse() {
        return rawResponse;
    }

    /**
     * Gets the state of the ATI performed, waits for the ATI response for max
     * period of timeout specified, returns null if response not arrived in
     * specified time
     *
     * @param timeout the time to wait for response in milliseconds
     * @return
     */
    public ATIState getState(long timeout) {
        synchronized (atiReq) {
            while (!atiResponseRecieved) {
                try {
                    atiReq.wait(timeout);
                } catch (InterruptedException ex) {
                    logger.error("Error waiting on atiReq while trying to get aitState", ex);
                }
            }
        }
        if ("".equals(this.rawResponse)) {
            //Response not recieved yet
            logger.info("[" + refID + "] ATI Response not recived yet");
            return null;
        }

        ATIState atiState = new ATIState(this.rawResponse);
        return atiState;
    }

Problem:

firstATIState = atiReq.getState(1000); 

This line, in the main class, doesnt terminate after 1 sec, as you can see the corresponding code in getState(long timeout) method

 while (!atiResponseRecieved) {
                    try {
                        atiReq.wait(timeout);
                    } catch (InterruptedException ex) {
                        logger.error("Error waiting on atiReq while trying to get aitState", ex);
                    }
                }

is in a loop so I believe even if atiReq.wait(timeout) returns within 1 sec and if atiResponseRecieved is not true, it keeps on looping till the timeout of the Now() method exhausts and it sets atiResponseRecieved to true;

Question:

1. How do I solve this? I have tried removing it from the loop but then "spurious awakes" dont let it wait for complete 1 sec.

2. Is there any other work around for this?

Answer 1

You can use Futuretask (or just Future). for this. It has a get() method that allows you to specify a timeout.