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.client5.http.examples.fluent;
28
29 import java.util.LinkedList;
30 import java.util.Queue;
31 import java.util.concurrent.ExecutionException;
32 import java.util.concurrent.ExecutorService;
33 import java.util.concurrent.Executors;
34 import java.util.concurrent.Future;
35
36 import org.apache.hc.client5.http.fluent.Async;
37 import org.apache.hc.client5.http.fluent.Content;
38 import org.apache.hc.client5.http.fluent.Request;
39 import org.apache.hc.core5.concurrent.FutureCallback;
40
41 /**
42 * This example demonstrates how the he HttpClient fluent API can be used to execute multiple
43 * requests asynchronously using background threads.
44 */
45 public class FluentAsync {
46
47 public static void main(final String... args)throws Exception {
48 // Use pool of two threads
49 final ExecutorService threadpool = Executors.newFixedThreadPool(2);
50 final Async async = Async.newInstance().use(threadpool);
51
52 final Request[] requests = new Request[] {
53 Request.get("http://www.google.com/"),
54 Request.get("http://www.yahoo.com/"),
55 Request.get("http://www.apache.org/"),
56 Request.get("http://www.apple.com/")
57 };
58
59
60 final Queue<Future<Content>> queue = new LinkedList<>();
61 // Execute requests asynchronously
62 for (final Request request: requests) {
63 final Future<Content> future = async.execute(request, new FutureCallback<Content>() {
64
65 @Override
66 public void failed(final Exception ex) {
67 System.out.println(ex.getMessage() + ": " + request);
68 }
69
70 @Override
71 public void completed(final Content content) {
72 System.out.println("Request completed: " + request);
73 }
74
75 @Override
76 public void cancelled() {
77 }
78
79 });
80 queue.add(future);
81 }
82
83 while(!queue.isEmpty()) {
84 final Future<Content> future = queue.remove();
85 try {
86 future.get();
87 } catch (final ExecutionException ex) {
88 }
89 }
90 System.out.println("Done");
91 threadpool.shutdown();
92 }
93
94 }