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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   * @version $Id: PrintStreamHandler.java 681956 2008-08-02 11:43:44Z dennisl $
28   * @since 2.0.9
29   */
30  public class PrintStreamHandler
31      implements InvocationOutputHandler
32  {
33  
34      /**
35       * The print stream to write to, never <code>null</code>.
36       */
37      private PrintStream out;
38  
39      /**
40       * A flag whether the print stream should be flushed after each line.
41       */
42      private boolean alwaysFlush;
43  
44      /**
45       * Creates a new output handler that writes to {@link System#out}.
46       */
47      public PrintStreamHandler()
48      {
49          this( System.out, false );
50      }
51  
52      /**
53       * Creates a new output handler that writes to the specified print stream.
54       * 
55       * @param out The print stream to write to, must not be <code>null</code>.
56       * @param alwaysFlush A flag whether the print stream should be flushed after each line.
57       */
58      public PrintStreamHandler( PrintStream out, boolean alwaysFlush )
59      {
60          if ( out == null )
61          {
62              throw new NullPointerException( "missing output stream" );
63          }
64          this.out = out;
65          this.alwaysFlush = alwaysFlush;
66      }
67  
68      public void consumeLine( String line )
69      {
70          if ( line == null )
71          {
72              out.println();
73          }
74          else
75          {
76              out.println( line );
77          }
78  
79          if ( alwaysFlush )
80          {
81              out.flush();
82          }
83      }
84  
85  }