    001/*
    002    Licensed to the Apache Software Foundation (ASF) under one
    003    or more contributor license agreements.  See the NOTICE file
    004    distributed with this work for additional information
    005    regarding copyright ownership.  The ASF licenses this file
    006    to you under the Apache License, Version 2.0 (the
    007    "License"); you may not use this file except in compliance
    008    with the License.  You may obtain a copy of the License at
    009
    010       http://www.apache.org/licenses/LICENSE-2.0
    011
    012    Unless required by applicable law or agreed to in writing,
    013    software distributed under the License is distributed on an
    014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015    KIND, either express or implied.  See the License for the
    016    specific language governing permissions and limitations
    017    under the License.
    018 */
    019package org.apache.wiki.htmltowiki;
    020
    021import java.io.IOException;
    022import java.io.Writer;
    023import java.util.regex.Matcher;
    024import java.util.regex.Pattern;
    025
    026/**
    027 * Part of the XHtmlToWikiTranslator.
    028 *
    029 */
    030// FIXME: Needs a better description as to how it works.
    031public class WhitespaceTrimWriter extends Writer {
    032
    033    private final StringBuffer m_result = new StringBuffer();
    034
    035    private StringBuffer m_buffer = new StringBuffer();
    036
    037    private boolean m_trimMode = true;
    038
    039    public static final String NO_TRIMMED_SPACE = "&nbsp;";
    040    private static final Pattern ONLINE_PATTERN = Pattern.compile( ".*?\\n\\s*?", Pattern.MULTILINE );
    041
    042    private boolean m_currentlyOnLineBegin = true;
    043
    044    /**
    045     *  {@inheritDoc}
    046     */
    047    @Override
    048    public void flush()
    049    {
    050        if( m_buffer.length() > 0 )
    051        {
    052            String s = m_buffer.toString();
    053            s = s.replaceAll( "\r\n", "\n" );
    054            if( m_trimMode )
    055            {
    056                s = s.replaceAll( "(\\w+) \\[\\?\\|Edit\\.jsp\\?page=\\1\\]", "[$1]" );
    057                s = s.replaceAll( "\n{2,}", "\n\n" );
    058                s = s.replaceAll( "\\p{Blank}+", " " );
    059                s = s.replaceAll( "[ ]*\n[ ]*", "\n" );
    060                s = replacePluginNewlineBackslashes( s );
    061                s = s.replace( NO_TRIMMED_SPACE, " " );
    062            }
    063            m_result.append( s );
    064            m_buffer = new StringBuffer();
    065        }
    066    }
    067
    068    private String replacePluginNewlineBackslashes( String s )
    069    {
    070        final Pattern p = Pattern.compile( "\\{\\{\\{(.*?)\\}\\}\\}|\\{\\{(.*?)\\}\\}|\\[\\{(.*?)\\}\\]", Pattern.DOTALL
    071                                                                                                    + Pattern.MULTILINE );
    072        final Matcher m = p.matcher( s );
    073        final StringBuffer sb = new StringBuffer();
    074        while( m.find() )
    075        {
    076            final String groupEscaped = m.group().replaceAll( "\\\\|\\$", "\\\\$0" );
    077            if( m.group( 3 ) != null )
    078            {
    079                m.appendReplacement( sb, groupEscaped.replaceAll( "\\\\\\\\\\\\\\\\", "\n" ) );
    080            }
    081            else
    082            {
    083                m.appendReplacement( sb, groupEscaped );
    084            }
    085        }
    086        m.appendTail( sb );
    087        s = sb.toString();
    088        return s;
    089    }
    090
    091    /**
    092     *  Returns true, if this Writer is currently trimming any whitespaces.
    093     *
    094     *  @return True, if trimming.
    095     */
    096    public boolean isWhitespaceTrimMode()
    097    {
    098        return m_trimMode;
    099    }
    100
    101    /**
    102     *  Set the trimming mode on/off.
    103     *
    104     *  @param trimMode True, if you want trimming to be turned on.  False otherwise.
    105     */
    106    public void setWhitespaceTrimMode(final boolean trimMode )
    107    {
    108        if( m_trimMode != trimMode )
    109        {
    110            flush();
    111            m_trimMode = trimMode;
    112        }
    113    }
    114
    115    /**
    116     *  {@inheritDoc}
    117     */
    118    @Override
    119    public void write(final char[] arg0, final int arg1, final int arg2 ) throws IOException
    120    {
    121        m_buffer.append( arg0, arg1, arg2 );
    122        m_currentlyOnLineBegin = ONLINE_PATTERN.matcher( m_buffer ).matches();
    123    }
    124
    125    /**
    126     *  {@inheritDoc}
    127     */
    128    @Override
    129    public void close() throws IOException
    130    {}
    131
    132    /**
    133     *  {@inheritDoc}
    134     */
    135    @Override
    136    public String toString()
    137    {
    138        flush();
    139        return m_result.toString();
    140    }
    141
    142    /**
    143     *  Returns true, if the writer is currently writing a line start.
    144     *
    145     *  @return True or false.
    146     */
    147    public boolean isCurrentlyOnLineBegin()
    148    {
    149        return m_currentlyOnLineBegin;
    150    }
    151}