io.netty.util.concurrent.PromiseCombiner Maven / Gradle / Ivy
/*
* Copyright 2016 The Netty Project
*
* The Netty Project 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 io.netty.util.concurrent;
import io.netty.util.internal.ObjectUtil;
public final class PromiseCombiner {
private int expectedCount;
private int doneCount;
private boolean doneAdding;
private Promise aggregatePromise;
private Throwable cause;
private final GenericFutureListener> listener = new GenericFutureListener>() {
@Override
public void operationComplete(Future future) throws Exception {
++doneCount;
if (!future.isSuccess() && cause == null) {
cause = future.cause();
}
if (doneCount == expectedCount && doneAdding) {
tryPromise();
}
}
};
@SuppressWarnings({ "unchecked", "rawtypes" })
public void add(Promise promise) {
checkAddAllowed();
++expectedCount;
promise.addListener(listener);
}
@SuppressWarnings({ "unchecked", "rawtypes" })
public void addAll(Promise... promises) {
checkAddAllowed();
expectedCount += promises.length;
for (Promise promise : promises) {
promise.addListener(listener);
}
}
public void finish(Promise aggregatePromise) {
if (doneAdding) {
throw new IllegalStateException("Already finished");
}
doneAdding = true;
this.aggregatePromise = ObjectUtil.checkNotNull(aggregatePromise, "aggregatePromise");
if (doneCount == expectedCount) {
tryPromise();
}
}
private boolean tryPromise() {
return (cause == null) ? aggregatePromise.trySuccess(null) : aggregatePromise.tryFailure(cause);
}
private void checkAddAllowed() {
if (doneAdding) {
throw new IllegalStateException("Adding promises is not allowed after finished adding");
}
}
}