1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27 package org.apache.hc.core5.http2.impl.nio.bootstrap;
28
29 import java.util.concurrent.atomic.AtomicBoolean;
30 import java.util.concurrent.atomic.AtomicReference;
31
32 import org.apache.hc.core5.concurrent.Cancellable;
33 import org.apache.hc.core5.concurrent.CancellableDependency;
34
35 final class CancellableExecution implements CancellableDependency {
36
37 private final AtomicBoolean cancelled;
38 private final AtomicReference<Cancellable> dependencyRef;
39
40 CancellableExecution() {
41 this.cancelled = new AtomicBoolean(false);
42 this.dependencyRef = new AtomicReference<>(null);
43 }
44
45 @Override
46 public void setDependency(final Cancellable cancellable) {
47 dependencyRef.set(cancellable);
48 if (cancelled.get()) {
49 final Cancellable dependency = dependencyRef.getAndSet(null);
50 if (dependency != null) {
51 dependency.cancel();
52 }
53 }
54 }
55
56 @Override
57 public boolean isCancelled() {
58 return cancelled.get();
59 }
60
61 @Override
62 public boolean cancel() {
63 if (cancelled.compareAndSet(false, true)) {
64 final Cancellable dependency = dependencyRef.getAndSet(null);
65 if (dependency != null) {
66 dependency.cancel();
67 }
68 return true;
69 }
70 return false;
71 }
72
73 }