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 javax.servlet.jsp.JspException;
024    import javax.servlet.jsp.PageContext;
025    import javax.servlet.jsp.tagext.BodyTagSupport;
026    import javax.servlet.jsp.tagext.TryCatchFinally;
027    
028    import org.apache.log4j.Logger;
029    
030    import org.apache.wiki.WikiContext;
031    
032    
033    /**
034     *  This is a class that provides the same services as the WikiTagBase, but this time it
035     *   works for the BodyTagSupport base class.
036     */
037    public abstract class WikiBodyTag extends BodyTagSupport implements TryCatchFinally {
038    
039        private static final long serialVersionUID = -6732266865112847897L;
040        protected WikiContext m_wikiContext;
041        private static final Logger log = Logger.getLogger( WikiBodyTag.class );
042    
043        public int doStartTag() throws JspException
044        {
045            try
046            {
047                m_wikiContext = (WikiContext) pageContext.getAttribute( WikiTagBase.ATTR_CONTEXT,
048                                                                        PageContext.REQUEST_SCOPE );
049    
050                if( m_wikiContext == null )
051                {
052                    throw new JspException("WikiContext may not be NULL - serious internal problem!");
053                }
054    
055                return doWikiStartTag();
056            }
057            catch( Exception e )
058            {
059                log.error( "Tag failed", e );
060                throw new JspException( "Tag failed, check logs: "+e.getMessage() );
061            }
062        }
063    
064        /**
065         * A local stub for doing tags.  This is just called after the local variables
066         * have been set.
067         * @return As doStartTag()
068         * @throws JspException
069         * @throws IOException
070         */
071        public abstract int doWikiStartTag() throws JspException, IOException;
072    
073        public void doCatch(Throwable arg0) throws Throwable
074        {
075        }
076    
077        public void doFinally()
078        {
079            m_wikiContext = null;
080        }  
081        
082        
083    }