我需要?jiǎng)?chuàng)建一個(gè)新線程，當(dāng)且僅當(dāng)主 ListenerAdapter 內(nèi)更新 MessageReceivedEvent 時(shí)才會(huì)執(zhí)行一個(gè)方法，并在變量未更新時(shí)讓線程休眠。該線程應(yīng)獨(dú)立于主線程運(yùn)行，并且不會(huì)停止新請(qǐng)求。這是線程類，private static final class Worker extends Thread { private volatile boolean running = false;MessageReceivedEvent event; //this must update along with the listener private boolean validateData() { if (//something) { return true; } return false; } private void waitForInput() { boolean hasInput = false; try { while (!hasInput) { hasInput = validateData(); if (!hasInput) { Thread.sleep(10); } } } catch (InterruptedException iex) { Thread.currentThread().interrupt(); } } @Override public void run() { running = true; while (running) { waitForInput(); //do something } } }它是一個(gè)由主線程請(qǐng)求運(yùn)行的內(nèi)部類，只有當(dāng)來自偵聽器的實(shí)際事件發(fā)生變化時(shí)，才必須更新其中的 MessageReceivedEvent，否則它不應(yīng)該執(zhí)行任何操作。測(cè)試時(shí)，只會(huì)根據(jù)觸發(fā)該線程的MessageEvent執(zhí)行，如何讓該線程接收到更新？public class Listener extends ListenerAdapter { public static MessageReceivedEvent msgEvnt; @Override public void onMessageReceived(MessageReceivedEvent msgEvnt) { Listener.msgEvnt = msgEvnt; }這就是偵聽器所做的全部工作，每當(dāng)有新的 messageEvent 時(shí)就更新變量。
1 回答
慕容708150
TA貢獻(xiàn)1831條經(jīng)驗(yàn) 獲得超4個(gè)贊
您可以使用條件變量來完成此操作。
final ReentrantLock lock = new ReentrantLock();
final Condition condition = lock.newCondition();
private void waitForInput() {
? ? lock.lock();
? ? Listener.msgEvnt = null;
? ? try {
? ? ? ? while (Listener.msgEvnt == null)
? ? ? ? ? ? condition.await();
? ? } catch (InterruptedException e) {
? ? ? ? e.printStackTrace();
? ? } finally {
? ? ? ? lock.unlock();
? ? }
}
@Override
public void onMessageReceived(MessageReceivedEvent event) {
? ? lock.lock();
? ? try {
? ? ? ? Listener.msgEvnt = msgEvnt;
? ? ? ? condition.signal();
? ? } finally {
? ? ? ? lock.unlock();
? ? }
}
請(qǐng)參閱可重入鎖和條件
您可以使用阻塞隊(duì)列
final BlockingQueue queue = new ConcurrentBlockingQueue();
private MessageReceivedEvent waitForInput() throws InterruptedException {
? ? return queue.take();
}
@Override
public void onMessageReceived(MessageReceivedEvent event) {
? ? queue.put(event);
}
您可以使用Callback，這是我推薦的。
Consumer<? super MessageReceivedEvent> callback;
private void onInput(Consumer<? super MessageReceivedEvent> callback) {
? ? this.callback = callback;
}
@Override
public void onMessageReceived(MessageReceivedEvent event) {
? ? if (this.callback != null)
? ? ? ? this.callback.accept(event);
? ? this.callback = null;
}
使用示例：
listener.waitForInput(event -> {
? ? System.out.printf("%#s: %s\n", event.getAuthor(), event.getMessage().getContentDisplay());
});
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