portletrendertag.java

portal越来越流行了

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.pluto.driver.tags;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

/**
 * The portlet render tag is used to print portlet rendering result (or error
 * details) to the page.
 *
 * @version 1.0
 * @since Oct 4, 2004
 */
public class PortletRenderTag extends TagSupport {
	
	// TagSupport Impl ---------------------------------------------------------
	
	/**
	 * 
	 * @see PortletTag
	 */
    public int doEndTag() throws JspException {
    	
    	// Ensure that the portlet render tag resides within a portlet tag.
        PortletTag parentTag = (PortletTag) TagSupport.findAncestorWithClass(
        		this, PortletTag.class);
        if (parentTag == null) {
            throw new JspException("Portlet render tag may only reside "
            		+ "within a pluto:portlet tag.");
        }
        
        // If the portlet is rendered successfully, print the rendering result.
        if (parentTag.getStatus() == PortletTag.SUCCESS) {
            try {
                StringBuffer buffer = parentTag.getPortalServletResponse()
                		.getInternalBuffer().getBuffer();
                pageContext.getOut().print(buffer.toString());
            } catch (IOException ex) {
                throw new JspException(ex);
            }
        }
        // Otherwise, print the error stack trace.
        else {
            try {
                pageContext.getOut().print("Error rendering portlet.");
                pageContext.getOut().print("<pre>");
                parentTag.getThrowable().printStackTrace(
                		new PrintWriter(pageContext.getOut()));
                pageContext.getOut().print("</pre>");
            } catch (IOException ex) {
                throw new JspException(ex);
            }
        }
        
        // Return.
        return SKIP_BODY;
    }


}