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     */
019    package org.apache.wiki.tags;
020    
021    import java.io.IOException;
022    
023    import org.apache.wiki.WikiPage;
024    
025    /**
026     *  Outputs the version number of the previous version of this page.
027     *
028     *  @since 2.2
029     */
030    public class PreviousVersionTag
031        extends WikiTagBase
032    {
033        private static final long serialVersionUID = 0L;
034        
035        /**
036         *  {@inheritDoc}
037         */
038        @Override
039        public final int doWikiStartTag()
040            throws IOException
041        {
042            WikiPage   page   = m_wikiContext.getPage();
043    
044            int version = page.getVersion();
045    
046            version--;
047    
048            if( version > 0 )
049                pageContext.getOut().print( version );
050    
051            return SKIP_BODY;
052        }
053    }