我需要創建一個新線程，當且僅當主 ListenerAdapter 內更新 MessageReceivedEvent 時才會執行一個方法，并在變量未更新時讓線程休眠。該線程應獨立于主線程運行，并且不會停止新請求。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 } } }它是一個由主線程請求運行的內部類，只有當來自偵聽器的實際事件發生變化時，才必須更新其中的 MessageReceivedEvent，否則它不應該執行任何操作。測試時，只會根據觸發該線程的MessageEvent執行，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，每當有新的 messageEvent 時就更新變量。
1 回答
慕容708150
TA貢獻1831條經驗 獲得超4個贊
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();
? ? }
}
請參閱可重入鎖和條件
您可以使用阻塞隊列
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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