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1   package org.apache.maven.shared.invoker;
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 java.io.PrintStream;
23  
24  /**
25   * Offers an output handler that writes to a print stream like {@link System#out}.
26   *
27   * @since 2.0.9
28   */
29  public class PrintStreamHandler
30      implements InvocationOutputHandler
31  {
32  
33      /**
34       * The print stream to write to, never <code>null</code>.
35       */
36      private PrintStream out;
37  
38      /**
39       * A flag whether the print stream should be flushed after each line.
40       */
41      private boolean alwaysFlush;
42  
43      /**
44       * Creates a new output handler that writes to {@link System#out}.
45       */
46      public PrintStreamHandler()
47      {
48          this( System.out, false );
49      }
50  
51      /**
52       * Creates a new output handler that writes to the specified print stream.
53       * 
54       * @param out The print stream to write to, must not be <code>null</code>.
55       * @param alwaysFlush A flag whether the print stream should be flushed after each line.
56       */
57      public PrintStreamHandler( PrintStream out, boolean alwaysFlush )
58      {
59          if ( out == null )
60          {
61              throw new NullPointerException( "missing output stream" );
62          }
63          this.out = out;
64          this.alwaysFlush = alwaysFlush;
65      }
66  
67      public void consumeLine( String line )
68      {
69          if ( line == null )
70          {
71              out.println();
72          }
73          else
74          {
75              out.println( line );
76          }
77  
78          if ( alwaysFlush )
79          {
80              out.flush();
81          }
82      }
83  
84  }