/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.connect.util;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
public class TestFuture<T> implements Future<T> {
private volatile boolean resolved;
private T result;
private Throwable exception;
private CountDownLatch getCalledLatch;
private volatile boolean resolveOnGet;
private T resolveOnGetResult;
private Throwable resolveOnGetException;
public TestFuture() {
resolved = false;
getCalledLatch = new CountDownLatch(1);
resolveOnGet = false;
resolveOnGetResult = null;
resolveOnGetException = null;
}
public void resolve(T val) {
this.result = val;
resolved = true;
synchronized (this) {
this.notifyAll();
}
}
public void resolve(Throwable t) {
exception = t;
resolved = true;
synchronized (this) {
this.notifyAll();
}
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
return false;
}
@Override
public boolean isCancelled() {
return false;
}
@Override
public boolean isDone() {
return resolved;
}
@Override
public T get() throws InterruptedException, ExecutionException {
getCalledLatch.countDown();
while (true) {
try {
return get(Integer.MAX_VALUE, TimeUnit.DAYS);
} catch (TimeoutException e) {
// ignore
}
}
}
@Override
public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
getCalledLatch.countDown();
if (resolveOnGet) {
if (resolveOnGetException != null)
resolve(resolveOnGetException);
else
resolve(resolveOnGetResult);
}
synchronized (this) {
while (!resolved) {
this.wait(TimeUnit.MILLISECONDS.convert(timeout, unit));
}
}
if (exception != null) {
if (exception instanceof TimeoutException)
throw (TimeoutException) exception;
else if (exception instanceof InterruptedException)
throw (InterruptedException) exception;
else
throw new ExecutionException(exception);
}
return result;
}
/**
* Set a flag to resolve the future as soon as one of the get() methods has been called. Returns immediately.
* @param val the value to return from the future
*/
public void resolveOnGet(T val) {
resolveOnGet = true;
resolveOnGetResult = val;
}
/**
* Set a flag to resolve the future as soon as one of the get() methods has been called. Returns immediately.
* @param t the exception to return from the future
*/
public void resolveOnGet(Throwable t) {
resolveOnGet = true;
resolveOnGetException = t;
}
/**
* Block, waiting for another thread to call one of the get() methods, and then immediately resolve the future with
* the specified value.
* @param val the value to return from the future
*/
public void waitForGetAndResolve(T val) {
waitForGet();
resolve(val);
}
/**
* Block, waiting for another thread to call one of the get() methods, and then immediately resolve the future with
* the specified value.
* @param t the exception to use to resolve the future
*/
public void waitForGetAndResolve(Throwable t) {
waitForGet();
resolve(t);
}
private void waitForGet() {
try {
getCalledLatch.await();
} catch (InterruptedException e) {
throw new RuntimeException("Unexpected interruption: ", e);
}
}
}