1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.maven.shared.utils.cli;
20
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.io.OutputStream;
24 import java.util.Objects;
25
26 /**
27 * Poll InputStream for available data and write the output to an OutputStream.
28 *
29 * @author <a href="mailto:trygvis@inamo.no">Trygve Laugstøl</a>
30 */
31 class StreamPollFeeder extends Thread {
32
33 public static final int BUF_LEN = 80;
34
35 private final InputStream input;
36 private final OutputStream output;
37
38 private Throwable exception;
39
40 private boolean done;
41 private final Object lock = new Object();
42
43 /**
44 * Create a new StreamPollFeeder
45 *
46 * @param input Stream to read from
47 * @param output Stream to write to
48 */
49 StreamPollFeeder(InputStream input, OutputStream output) {
50 this.input = Objects.requireNonNull(input);
51 this.output = Objects.requireNonNull(output);
52 this.done = false;
53 }
54
55 @Override
56 public void run() {
57
58 byte[] buf = new byte[BUF_LEN];
59
60 try {
61 while (!done) {
62 if (input.available() > 0) {
63 int i = input.read(buf);
64 if (i > 0) {
65 output.write(buf, 0, i);
66 output.flush();
67 } else {
68 done = true;
69 }
70 } else {
71 synchronized (lock) {
72 if (!done) {
73 lock.wait(100);
74 }
75 }
76 }
77 }
78 } catch (IOException e) {
79 exception = e;
80 } catch (InterruptedException e) {
81 Thread.currentThread().interrupt();
82 } finally {
83 close();
84 }
85 }
86
87 private void close() {
88 try {
89 output.close();
90 } catch (IOException e) {
91 if (exception == null) {
92 exception = e;
93 }
94 }
95 }
96
97 /**
98 * @since 3.2.0
99 */
100 public Throwable getException() {
101 return this.exception;
102 }
103
104 public void waitUntilDone() {
105
106 synchronized (lock) {
107 done = true;
108 lock.notifyAll();
109 }
110
111 try {
112 join();
113 } catch (InterruptedException e) {
114 Thread.currentThread().interrupt();
115 }
116 }
117 }