001/*
002 *   Copyright (C) Christian Schulte, 2005-206
003 *   All rights reserved.
004 *
005 *   Redistribution and use in source and binary forms, with or without
006 *   modification, are permitted provided that the following conditions
007 *   are met:
008 *
009 *     o Redistributions of source code must retain the above copyright
010 *       notice, this list of conditions and the following disclaimer.
011 *
012 *     o Redistributions in binary form must reproduce the above copyright
013 *       notice, this list of conditions and the following disclaimer in
014 *       the documentation and/or other materials provided with the
015 *       distribution.
016 *
017 *   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
018 *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
019 *   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
020 *   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
021 *   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
022 *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
023 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
024 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
025 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
026 *   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
027 *
028 *   $JOMC: TrailingWhitespaceEditor.java 4613 2012-09-22 10:07:08Z schulte $
029 *
030 */
031package org.jomc.util;
032
033/**
034 * {@code LineEditor} removing trailing whitespace.
035 *
036 * @author <a href="mailto:cs@schulte.it">Christian Schulte</a>
037 * @version $JOMC: TrailingWhitespaceEditor.java 4613 2012-09-22 10:07:08Z schulte $
038 *
039 * @see #edit(java.lang.String)
040 */
041public final class TrailingWhitespaceEditor extends LineEditor
042{
043
044    /** Creates a new {@code TrailingWhitespaceEditor} instance. */
045    public TrailingWhitespaceEditor()
046    {
047        this( null, null );
048    }
049
050    /**
051     * Creates a new {@code TrailingWhitespaceEditor} instance taking a string to use for separating lines.
052     *
053     * @param lineSeparator String to use for separating lines.
054     */
055    public TrailingWhitespaceEditor( final String lineSeparator )
056    {
057        this( null, lineSeparator );
058    }
059
060    /**
061     * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain.
062     *
063     * @param editor The editor to chain.
064     */
065    public TrailingWhitespaceEditor( final LineEditor editor )
066    {
067        this( editor, null );
068    }
069
070    /**
071     * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain and a string to use for
072     * separating lines.
073     *
074     * @param editor The editor to chain.
075     * @param lineSeparator String to use for separating lines.
076     */
077    public TrailingWhitespaceEditor( final LineEditor editor, final String lineSeparator )
078    {
079        super( editor, lineSeparator );
080    }
081
082    /**
083     * {@inheritDoc}
084     * <p>This method returns {@code line} with any trailing whitespace characters removed.</p>
085     *
086     * @see Character#isWhitespace(char)
087     */
088    @Override
089    protected String editLine( final String line )
090    {
091        String replacement = line;
092
093        if ( line != null )
094        {
095            StringBuilder whitespace = null;
096            boolean sawWhitespace = false;
097            final StringBuilder buf = new StringBuilder( line.length() );
098            final char[] chars = line.toCharArray();
099
100            for ( int i = 0; i < chars.length; i++ )
101            {
102                if ( Character.isWhitespace( chars[i] ) )
103                {
104                    if ( whitespace == null )
105                    {
106                        whitespace = new StringBuilder( line.length() );
107                    }
108
109                    whitespace.append( chars[i] );
110                    sawWhitespace = true;
111                }
112                else
113                {
114                    if ( sawWhitespace )
115                    {
116                        buf.append( whitespace );
117                        sawWhitespace = false;
118                        whitespace = null;
119                    }
120                    buf.append( chars[i] );
121                }
122            }
123
124            replacement = buf.toString();
125        }
126
127        return replacement;
128    }
129
130}