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1   /*
2    *   Copyright (C) 2005 Christian Schulte <cs@schulte.it>
3    *   All rights reserved.
4    *
5    *   Redistribution and use in source and binary forms, with or without
6    *   modification, are permitted provided that the following conditions
7    *   are met:
8    *
9    *     o Redistributions of source code must retain the above copyright
10   *       notice, this list of conditions and the following disclaimer.
11   *
12   *     o Redistributions in binary form must reproduce the above copyright
13   *       notice, this list of conditions and the following disclaimer in
14   *       the documentation and/or other materials provided with the
15   *       distribution.
16   *
17   *   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
18   *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
19   *   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
20   *   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
21   *   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22   *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23   *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24   *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25   *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26   *   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27   *
28   *   $JOMC: TrailingWhitespaceEditor.java 5091 2016-04-04 15:40:17Z schulte $
29   *
30   */
31  package org.jomc.util;
32  
33  /**
34   * {@code LineEditor} removing trailing whitespace.
35   *
36   * @author <a href="mailto:cs@schulte.it">Christian Schulte</a>
37   * @version $JOMC: TrailingWhitespaceEditor.java 5091 2016-04-04 15:40:17Z schulte $
38   *
39   * @see #edit(java.lang.String)
40   */
41  public final class TrailingWhitespaceEditor extends LineEditor
42  {
43  
44      /**
45       * Creates a new {@code TrailingWhitespaceEditor} instance.
46       */
47      public TrailingWhitespaceEditor()
48      {
49          this( null, null );
50      }
51  
52      /**
53       * Creates a new {@code TrailingWhitespaceEditor} instance taking a string to use for separating lines.
54       *
55       * @param lineSeparator String to use for separating lines.
56       */
57      public TrailingWhitespaceEditor( final String lineSeparator )
58      {
59          this( null, lineSeparator );
60      }
61  
62      /**
63       * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain.
64       *
65       * @param editor The editor to chain.
66       */
67      public TrailingWhitespaceEditor( final LineEditor editor )
68      {
69          this( editor, null );
70      }
71  
72      /**
73       * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain and a string to use for
74       * separating lines.
75       *
76       * @param editor The editor to chain.
77       * @param lineSeparator String to use for separating lines.
78       */
79      public TrailingWhitespaceEditor( final LineEditor editor, final String lineSeparator )
80      {
81          super( editor, lineSeparator );
82      }
83  
84      /**
85       * {@inheritDoc}
86       * <p>
87       * This method returns {@code line} with any trailing whitespace characters removed.
88       * </p>
89       *
90       * @see Character#isWhitespace(char)
91       */
92      @Override
93      protected String editLine( final String line )
94      {
95          String replacement = line;
96  
97          if ( line != null )
98          {
99              StringBuilder whitespace = null;
100             boolean sawWhitespace = false;
101             final StringBuilder buf = new StringBuilder( line.length() );
102             final char[] chars = line.toCharArray();
103 
104             for ( int i = 0; i < chars.length; i++ )
105             {
106                 if ( Character.isWhitespace( chars[i] ) )
107                 {
108                     if ( whitespace == null )
109                     {
110                         whitespace = new StringBuilder( line.length() );
111                     }
112 
113                     whitespace.append( chars[i] );
114                     sawWhitespace = true;
115                 }
116                 else
117                 {
118                     if ( sawWhitespace )
119                     {
120                         buf.append( whitespace );
121                         sawWhitespace = false;
122                         whitespace = null;
123                     }
124                     buf.append( chars[i] );
125                 }
126             }
127 
128             replacement = buf.toString();
129         }
130 
131         return replacement;
132     }
133 
134 }