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 3838 2011-10-08 20:15:41Z schulte2005 $
029     *
030     */
031    package org.jomc.util;
032    
033    /**
034     * {@code LineEditor} removing trailing whitespace.
035     *
036     * @author <a href="mailto:schulte2005@users.sourceforge.net">Christian Schulte</a>
037     * @version $JOMC: TrailingWhitespaceEditor.java 3838 2011-10-08 20:15:41Z schulte2005 $
038     *
039     * @see #edit(java.lang.String)
040     */
041    public 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    }