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.tags;
020
021import org.apache.wiki.InternalWikiException;
022import org.apache.wiki.api.core.Engine;
023import org.apache.wiki.api.core.Page;
024import org.apache.wiki.pages.PageManager;
025
026
027/**
028 *  Does a version check on the page.  Mode is as follows:
029 *  <UL>
030 *   <LI><b>latest</b> - Include body, if the page is the latest version.</li>
031 *   <LI><b>notlatest</b> - Include body, if the page is NOT the latest version.</li>
032 *   <li><b>first</b> - Include body, if page is the first version (version 1)</li>
033 *   <li><b>notfirst</b> - Include bodt, if page is NOT the first version (version 1)</li> 
034 *  </UL>
035 *  If the page does not exist, body content is never included.
036 *
037 *  @since 2.0
038 */
039public class CheckVersionTag extends WikiTagBase {
040
041    private static final long serialVersionUID = 0L;
042    
043    private enum VersionMode {
044        LATEST, NOTLATEST, FIRST, NOTFIRST
045    }
046
047    private VersionMode m_mode;
048
049    /**
050     * {@inheritDoc}
051     */
052    @Override
053    public void initTag() {
054        super.initTag();
055        m_mode = VersionMode.LATEST;
056    }
057
058    /**
059     *  Sets the mode.
060     *  
061     *  @param arg The mode to set.
062     */
063    public void setMode( final String arg ) {
064        if( "latest".equals(arg) ) {
065            m_mode = VersionMode.LATEST;
066        } else if( "notfirst".equals(arg) ) {
067            m_mode = VersionMode.NOTFIRST;
068        } else if( "first".equals(arg) ) {
069            m_mode = VersionMode.FIRST;
070        } else {
071            m_mode = VersionMode.NOTLATEST;
072        }
073    }
074
075    /**
076     *  {@inheritDoc}
077     */
078    @Override
079    public final int doWikiStartTag() {
080        final Engine engine = m_wikiContext.getEngine();
081        final Page page = m_wikiContext.getPage();
082
083        if( page != null && engine.getManager( PageManager.class ).wikiPageExists( page.getName() ) ) {
084            final int version = page.getVersion();
085            final boolean include;
086            final Page latest = engine.getManager( PageManager.class ).getPage( page.getName() );
087
088            switch( m_mode ) {
089                case LATEST    : include = ( version < 0 ) || ( latest.getVersion() == version ); break;
090                case NOTLATEST : include = ( version > 0 ) && ( latest.getVersion() != version ); break;
091                case FIRST     : include = ( version == 1 ) || ( version < 0 && latest.getVersion() == 1 ); break;
092                case NOTFIRST  : include = version > 1; break;
093                default: throw new InternalWikiException( "Mode which is not available!" );
094            }
095            if( include ) {
096                return EVAL_BODY_INCLUDE;
097            }
098        }
099        return SKIP_BODY;
100    }
101
102}