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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.surefire.booter.spi;
20  
21  import javax.annotation.Nonnull;
22  
23  import java.io.IOException;
24  import java.nio.channels.ReadableByteChannel;
25  
26  import org.apache.maven.surefire.api.booter.Command;
27  import org.apache.maven.surefire.api.booter.MasterProcessChannelDecoder;
28  import org.apache.maven.surefire.api.fork.ForkNodeArguments;
29  import org.apache.maven.surefire.api.stream.AbstractStreamDecoder.Memento;
30  import org.apache.maven.surefire.api.stream.MalformedChannelException;
31  import org.apache.maven.surefire.booter.stream.CommandDecoder;
32  
33  /**
34   * magic number : opcode [: opcode specific data]*
35   * <br>
36   *
37   * @author <a href="mailto:tibordigana@apache.org">Tibor Digana (tibor17)</a>
38   * @since 3.0.0-M5
39   */
40  public class CommandChannelDecoder implements MasterProcessChannelDecoder {
41      private final CommandDecoder decoder;
42      private Memento memento;
43  
44      public CommandChannelDecoder(@Nonnull ReadableByteChannel channel, @Nonnull ForkNodeArguments arguments) {
45          decoder = new CommandDecoder(channel, arguments);
46      }
47  
48      @Override
49      @Nonnull
50      @SuppressWarnings("checkstyle:innerassignment")
51      public Command decode() throws IOException {
52          if (memento == null) {
53              // do not create memento in constructor because the constructor is called in another thread
54              // memento is the thread confinement object
55              memento = decoder.new Memento();
56          }
57  
58          do {
59              try {
60                  Command command = decoder.decode(memento);
61                  if (command != null) {
62                      return command;
63                  }
64              } catch (MalformedChannelException e) {
65                  // a bad stream, already logged the stream down to a dump file or console, and continue till OEF
66              }
67          } while (true);
68      }
69  
70      @Override
71      public void close() throws IOException {
72          decoder.close();
73      }
74  }