insertdifftag.java

wiki建站资源 java编写的 很好用

/* 
    JSPWiki - a JSP-based WikiWiki clone.

    Copyright (C) 2001-2002 Janne Jalkanen ([e-mail])

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.ecyrd.jspwiki.tags;

import java.io.IOException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;

import com.ecyrd.jspwiki.WikiEngine;
import com.ecyrd.jspwiki.WikiPage;

/**
 *  Writes difference between two pages using a HTML table.  If there is
 *  no difference, includes the body.
 *
 *  <P><B>Attributes</B></P>
 *  <UL>
 *    <LI>page - Page name to refer to.  Default is the current page.
 *  </UL>
 *
 *  @author Janne Jalkanen
 *  @since 2.0
 */
public class InsertDiffTag
    extends WikiTagBase
{
    public static final String ATTR_OLDVERSION = "insertdiff.old";
    public static final String ATTR_NEWVERSION = "insertdiff.new";

    protected String m_pageName;

    public void setPage( String page )
    {
        m_pageName = page;
    }

    public String getPage()
    {
        return m_pageName;
    }

    public final int doWikiStartTag()
        throws IOException
    {
        WikiEngine engine = m_wikiContext.getEngine();
        WikiPage   page;

        if( m_pageName == null )
        {
            page = m_wikiContext.getPage();
        }
        else
        {
            page = engine.getPage( m_pageName );
        }

        Integer vernew = (Integer) pageContext.getAttribute( ATTR_NEWVERSION,
                                                             PageContext.REQUEST_SCOPE );
        Integer verold = (Integer) pageContext.getAttribute( ATTR_OLDVERSION,
                                                             PageContext.REQUEST_SCOPE );

        log.info("Request diff between version "+verold+" and "+vernew);

        if( page != null )
        {
            JspWriter out = pageContext.getOut();

            String diff = engine.getDiff( page.getName(), 
                                          vernew.intValue(), 
                                          verold.intValue() );

            if( diff.length() == 0 )
            {
                return EVAL_BODY_INCLUDE;
            }

            out.write( diff );
        }

        return SKIP_BODY;
    }
}