1 package org.apache.maven.plugin.surefire.booterclient.lazytestprovider;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.maven.surefire.api.booter.Command;
23
24 import java.io.IOException;
25
26 /**
27 * Reader stream sends commands to forked jvm std-{@link java.io.InputStream input-stream}.
28 *
29 * @author <a href="mailto:tibordigana@apache.org">Tibor Digana (tibor17)</a>
30 * @since 2.19
31 * @see Command
32 */
33 public abstract class DefaultCommandReader
34 extends AbstractCommandReader
35 {
36 /**
37 * Opposite to {@link #isClosed()}.
38 * @return {@code true} if not closed
39 */
40 protected boolean canContinue()
41 {
42 return !isClosed();
43 }
44
45 /**
46 * Possibly waiting for next command (see {@link #nextCommand()}) unless the stream is atomically
47 * closed (see {@link #isClosed()} returns {@code true}) before this method has returned.
48 *
49 * @throws IOException stream error while waiting for notification regarding next test required by forked jvm
50 */
51 protected void beforeNextCommand()
52 throws IOException
53 {
54 }
55
56 protected abstract Command nextCommand();
57
58 /**
59 * Used by single thread in StreamFeeder class.
60 *
61 * @return {@inheritDoc}
62 * @throws IOException {@inheritDoc}
63 */
64 @Override
65 public Command readNextCommand()
66 throws IOException
67 {
68 tryFlush();
69
70 if ( isClosed() )
71 {
72 return null;
73 }
74
75 if ( !canContinue() )
76 {
77 close();
78 return null;
79 }
80
81 beforeNextCommand();
82
83 if ( isClosed() )
84 {
85 return null;
86 }
87
88 return nextCommand();
89 }
90 }