    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.logging.log4j.LogManager;
    022import org.apache.logging.log4j.Logger;
    023import org.apache.wiki.api.core.Context;
    024import org.apache.wiki.api.core.Engine;
    025import org.apache.wiki.diff.DifferenceManager;
    026import org.apache.wiki.pages.PageManager;
    027
    028import javax.servlet.jsp.JspWriter;
    029import javax.servlet.jsp.PageContext;
    030import java.io.IOException;
    031
    032/**
    033 *  Writes difference between two pages using a HTML table.  If there is
    034 *  no difference, includes the body.
    035 *
    036 *  <P><B>Attributes</B></P>
    037 *  <UL>
    038 *    <LI>page - Page name to refer to.  Default is the current page.
    039 *  </UL>
    040 *
    041 *  @since 2.0
    042 */
    043public class InsertDiffTag extends WikiTagBase {
    044
    045    private static final long serialVersionUID = 0L;
    046    private static final Logger LOG = LogManager.getLogger( InsertDiffTag.class );
    047
    048    /** Attribute which is used to store the old page content to the Page Context */
    049    public static final String ATTR_OLDVERSION = "olddiff";
    050
    051    /** Attribute which is used to store the new page content to the Page Context */
    052    public static final String ATTR_NEWVERSION = "newdiff";
    053
    054    protected String m_pageName;
    055
    056    /** {@inheritDoc} */
    057    @Override public void initTag() {
    058        super.initTag();
    059        m_pageName = null;
    060    }
    061
    062    /**
    063     *  Sets the page name.
    064     *  @param page Page to get diff from.
    065     */
    066    public void setPage( final String page )
    067    {
    068        m_pageName = page;
    069    }
    070
    071    /**
    072     *  Gets the page name.
    073     * @return The page name.
    074     */
    075    public String getPage()
    076    {
    077        return m_pageName;
    078    }
    079
    080    /** {@inheritDoc} */
    081    @Override
    082    public final int doWikiStartTag() throws IOException {
    083        final Engine engine = m_wikiContext.getEngine();
    084        final Context ctx;
    085
    086        if( m_pageName == null ) {
    087            ctx = m_wikiContext;
    088        } else {
    089            ctx = m_wikiContext.clone();
    090            ctx.setPage( engine.getManager( PageManager.class ).getPage(m_pageName) );
    091        }
    092
    093        final Integer vernew = ( Integer )pageContext.getAttribute( ATTR_NEWVERSION, PageContext.REQUEST_SCOPE );
    094        final Integer verold = ( Integer )pageContext.getAttribute( ATTR_OLDVERSION, PageContext.REQUEST_SCOPE );
    095
    096        LOG.debug("Request diff between version "+verold+" and "+vernew);
    097
    098        if( ctx.getPage() != null ) {
    099            final JspWriter out = pageContext.getOut();
    100            final String diff = engine.getManager( DifferenceManager.class ).getDiff( ctx, vernew, verold);
    101
    102            if( diff.isEmpty() ) {
    103                return EVAL_BODY_INCLUDE;
    104            }
    105
    106            out.write( diff );
    107        }
    108
    109        return SKIP_BODY;
    110    }
    111
    112}
    113