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本文主要研究一下cheddar的PendingResult

PendingResult

Cheddar/cheddar/cheddar-application/src/main/java/com/clicktravel/cheddar/application/pending/result/PendingResult.java

class PendingResult {

    private static final long TIMEOUT_SECONDS = 30;
    private final CountDownLatch countdownLatch = new CountDownLatch(1);
    private Result result;

    /**
     * Offers a {@link Result}, returning immediately.
     * @param result {@link Result} to offer
     */
    public void offerResult(final Result result) {
        this.result = result;
        countdownLatch.countDown();
    }

    /**
     * Polls for a {@link Result}, blocking until it is offered by some other thread. If the result has already been
     * offered, the result is returned immediately.
     * @return {@link Result} obtained, potentially after blocking
     * @throws InterruptedException, PendingResultTimeoutException
     */
    public Result pollResult() throws InterruptedException, PendingResultTimeoutException {
        if (!countdownLatch.await(TIMEOUT_SECONDS, TimeUnit.SECONDS)) {
            throw new PendingResultTimeoutException();
        }
        return result;
    }
}
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