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.WikiEngine;
024    import org.apache.wiki.WikiPage;
025    import org.apache.wiki.PageManager;
026    import org.apache.wiki.PageLock;
027    import org.apache.wiki.api.exceptions.ProviderException;
028    
029    import javax.servlet.http.HttpSession;
030    
031    /**
032     *  Checks whether the page is locked for editing.  If the mode matches,
033     *  the tag body is included.  The "mode" can be any of the following:
034     *  
035     *  <ul>
036     *  <li><b>locked</b> - The page is currently locked, but the lock is owned by someone else.</li>
037     *  <li><b>owned</b> - The page is currently locked and the current user is the owner of the lock.</li>
038     *  <li><b>unlocked</b> - Nobody has locked the page.</li>
039     *  </ul>
040     *  
041     *  @since 2.0
042     */
043    public class CheckLockTag
044        extends WikiTagBase
045    {
046        private static final long serialVersionUID = 1L;
047        
048        private static enum LockState
049        {
050            LOCKED, NOTLOCKED, OWNED
051        }
052    
053        private LockState m_mode;
054    
055        /**
056         *  {@inheritDoc}
057         */
058        @Override
059        public void initTag()
060        {
061            super.initTag();
062            m_mode = LockState.NOTLOCKED;
063        }
064    
065        /**
066         *  Sets the mode to check for.
067         *  
068         *  @param arg A String for the mode.
069         */
070        public void setMode( String arg )
071        {
072            if( "locked".equals(arg) )
073            {
074                m_mode = LockState.LOCKED;
075            }
076            else if("owned".equals(arg) )
077            {
078                m_mode = LockState.OWNED;
079            }
080            else
081            {
082                m_mode = LockState.NOTLOCKED;
083            }
084        }
085    
086        /**
087         *  {@inheritDoc}
088         */
089        @Override
090        public final int doWikiStartTag()
091            throws IOException,
092                   ProviderException
093        {
094            WikiEngine engine = m_wikiContext.getEngine();
095            WikiPage   page   = m_wikiContext.getPage();
096    
097            if( page != null )
098            {
099                PageManager mgr = engine.getPageManager();
100    
101                PageLock lock = mgr.getCurrentLock( page );
102    
103                HttpSession session = pageContext.getSession();
104    
105                PageLock userLock = (PageLock) session.getAttribute("lock-"+page.getName());
106    
107                if( (lock != null && m_mode == LockState.LOCKED && lock != userLock ) ||
108                    (lock != null && m_mode == LockState.OWNED && lock == userLock ) ||
109                    (lock == null && m_mode == LockState.NOTLOCKED) )
110                {
111                    String tid = getId();
112    
113                    if( tid != null && lock != null )
114                    {
115                        pageContext.setAttribute( tid, lock );
116                    }
117    
118                    return EVAL_BODY_INCLUDE;
119                }
120            }
121    
122            return SKIP_BODY;
123        }
124    
125    }