ratpack.exec.internal.AsyncDownstream Maven / Gradle / Ivy
/*
* Copyright 2017 the original author or authors.
*
* Licensed 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 ratpack.exec.internal;
import ratpack.exec.Downstream;
import ratpack.exec.OverlappingExecutionException;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
class AsyncDownstream implements Downstream {
@SuppressWarnings("rawtypes")
private static final AtomicIntegerFieldUpdater FIRED_UPDATER = AtomicIntegerFieldUpdater.newUpdater(AsyncDownstream.class, "fired");
@SuppressWarnings("unused")
volatile int fired;
private final Continuation continuation;
private final Downstream downstream;
AsyncDownstream(Continuation continuation, Downstream downstream) {
this.continuation = continuation;
this.downstream = downstream;
}
boolean fire() {
return FIRED_UPDATER.compareAndSet(this, 0, 1);
}
@Override
public void error(Throwable throwable) {
if (fire()) {
continuation.resume(() -> downstream.error(throwable));
} else {
DefaultExecution.LOGGER.error("", new OverlappingExecutionException("promise already fulfilled", throwable));
}
}
@Override
public void success(T value) {
if (fire()) {
continuation.resume(() -> downstream.success(value));
} else {
DefaultExecution.LOGGER.error("", new OverlappingExecutionException("promise already fulfilled"));
}
}
@Override
public void complete() {
if (fire()) {
continuation.resume(downstream::complete);
} else {
DefaultExecution.LOGGER.error("", new OverlappingExecutionException("promise already fulfilled"));
}
}
}