TrailingWhitespaceEditor.java

/*
 *   Copyright (C) Christian Schulte <cs@schulte.it>, 2005-206
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     o Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     o Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 *   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 *   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 *   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *   $JOMC: TrailingWhitespaceEditor.java 5043 2015-05-27 07:03:39Z schulte $
 *
 */
package org.jomc.util;

/**
 * {@code LineEditor} removing trailing whitespace.
 *
 * @author <a href="mailto:cs@schulte.it">Christian Schulte</a>
 * @version $JOMC: TrailingWhitespaceEditor.java 5043 2015-05-27 07:03:39Z schulte $
 *
 * @see #edit(java.lang.String)
 */
public final class TrailingWhitespaceEditor extends LineEditor
{

    /**
     * Creates a new {@code TrailingWhitespaceEditor} instance.
     */
    public TrailingWhitespaceEditor()
    {
        this( null, null );
    }

    /**
     * Creates a new {@code TrailingWhitespaceEditor} instance taking a string to use for separating lines.
     *
     * @param lineSeparator String to use for separating lines.
     */
    public TrailingWhitespaceEditor( final String lineSeparator )
    {
        this( null, lineSeparator );
    }

    /**
     * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain.
     *
     * @param editor The editor to chain.
     */
    public TrailingWhitespaceEditor( final LineEditor editor )
    {
        this( editor, null );
    }

    /**
     * Creates a new {@code TrailingWhitespaceEditor} instance taking an editor to chain and a string to use for
     * separating lines.
     *
     * @param editor The editor to chain.
     * @param lineSeparator String to use for separating lines.
     */
    public TrailingWhitespaceEditor( final LineEditor editor, final String lineSeparator )
    {
        super( editor, lineSeparator );
    }

    /**
     * {@inheritDoc}
     * <p>
     * This method returns {@code line} with any trailing whitespace characters removed.
     * </p>
     *
     * @see Character#isWhitespace(char)
     */
    @Override
    protected String editLine( final String line )
    {
        String replacement = line;

        if ( line != null )
        {
            StringBuilder whitespace = null;
            boolean sawWhitespace = false;
            final StringBuilder buf = new StringBuilder( line.length() );
            final char[] chars = line.toCharArray();

            for ( int i = 0; i < chars.length; i++ )
            {
                if ( Character.isWhitespace( chars[i] ) )
                {
                    if ( whitespace == null )
                    {
                        whitespace = new StringBuilder( line.length() );
                    }

                    whitespace.append( chars[i] );
                    sawWhitespace = true;
                }
                else
                {
                    if ( sawWhitespace )
                    {
                        buf.append( whitespace );
                        sawWhitespace = false;
                        whitespace = null;
                    }
                    buf.append( chars[i] );
                }
            }

            replacement = buf.toString();
        }

        return replacement;
    }

}