abstractbodytag.java

基于struts框架的web开发应用实例

/**
 *
 * $Header: /raid1/wide/cvsroot/wide/dev/struts/struts-metadata/templates/new-app/nitroX-tour/site/WEB-INF/src/java/com/hp/mw/samples/struts/storefront/taglibs/AbstractBodyTag.java,v 1.1 2005/10/10 20:12:04 sami Exp $
 *
 * Copyright (c) 2002 by M7 Corporation
 * All rights reserved.
 *
 * The information contained herein is confidential and proprietary
 * to M7 Corporation, and considered a trade secret as defined under
 * civil and criminal statutes.  M7 Corporation shall pursue its
 * civil and criminal remedies in the event of unauthorized use or
 * misappropriation of its trade secrets.  Use of this information
 * by anyone other than authorized employees of M7 Corporation is
 * granted only under a written non-disclosure agreement, expressly
 * prescribing the scope and manner of such use.
 *
 */
package com.hp.mw.samples.struts.storefront.taglibs;

import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;


/**
 *
 * @author <a href="mailto:[e-mail]">Zaitrarrio Collier</a>
 * @version $ Revision: $
 */
public class AbstractBodyTag
    extends BodyTagSupport
{
  /**
    * Default value for <code>serialVersionUID</code> required for Serializable class
    */
   private static final long serialVersionUID = 1L;

    //~ Instance fields --------------------------------------------------------

    // tracks whether an exception has occurred while handling this page
    private boolean errors = false;

    //~ Methods ----------------------------------------------------------------

    /**
     * @see javax.servlet.jsp.tagext.BodyTag
     */
    public int doStartTag(  )
        throws JspException
    {
        try
        {
            pageContext.getOut(  ).write( getTagContent(  ) );
        }
        catch ( Exception e )
        {
            handlePageException( e );
        }

        return SKIP_BODY;
    }

    /**
     * @see javax.servlet.jsp.tagext.BodyTag
     */
    public int doEndTag(  )
        throws JspException
    {
        return errors
               ? SKIP_PAGE
               : EVAL_PAGE;
    }

    /**
     * method for returning the content of the tag, overridden by subclasses
     *
     * @return the output content for the tag
     */
    public String getTagContent(  )
    {
        return "";
    }

    /**
     * Handles exceptions which may occur while processing the page
     *
     * @param the exception that should be handled
     * @see javax.servlet.jsp.PageContext
     */
    public void handlePageException( Exception e )
        throws JspException
    {
        try
        {
            errors = true;
            pageContext.getRequest(  ).setAttribute( "javax.servlet.jsp.jspException", e );
            pageContext.handlePageException( e );
        }
        catch ( Exception ne )
        {
            throw new JspException( ne.getMessage(  ) );
        }
    }

    /**
     * Returns an http session from the servlet request
     *
     * @return the current http session
     */
    protected final HttpSession getSession( boolean create )
    {
        HttpServletRequest request = ( HttpServletRequest ) pageContext.getRequest(  );

        return request.getSession( create );
    }
}