| /* |
| * ==================================================================== |
| * 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| package org.apache.hc.core5.concurrent; |
| |
| import java.util.concurrent.atomic.AtomicMarkableReference; |
| |
| import org.apache.hc.core5.util.Args; |
| |
| /** |
| * {@link Cancellable} that has a dependency on another {@link Cancellable} |
| * process or operation. Dependent process or operation will get cancelled |
| * if this {@link Cancellable} itself is cancelled. |
| * |
| * @since 5.0 |
| */ |
| public final class ComplexCancellable implements CancellableDependency { |
| |
| private final AtomicMarkableReference<Cancellable> dependencyRef; |
| |
| public ComplexCancellable() { |
| this.dependencyRef = new AtomicMarkableReference<>(null, false); |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| return dependencyRef.isMarked(); |
| } |
| |
| @Override |
| public void setDependency(final Cancellable dependency) { |
| Args.notNull(dependency, "dependency"); |
| final Cancellable actualDependency = dependencyRef.getReference(); |
| if (!dependencyRef.compareAndSet(actualDependency, dependency, false, false)) { |
| dependency.cancel(); |
| } |
| } |
| |
| @Override |
| public boolean cancel() { |
| while (!dependencyRef.isMarked()) { |
| final Cancellable actualDependency = dependencyRef.getReference(); |
| if (dependencyRef.compareAndSet(actualDependency, actualDependency, false, true)) { |
| if (actualDependency != null) { |
| actualDependency.cancel(); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| } |