inserttag.java

sun公司的petstore,一个J2ee的示例应用程序.

/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN
 * OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
 * FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR
 * PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF
 * LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that Software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of
 * any nuclear facility.
 */

package com.sun.j2ee.blueprints.waf.view.template.tags;

// J2EE Imports
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.TagSupport;

import com.sun.j2ee.blueprints.waf.view.template.Parameter;
import com.sun.j2ee.blueprints.waf.view.template.Screen;

// WAF imports
import com.sun.j2ee.blueprints.waf.controller.web.util.WebKeys;

/**
 * This class is an easy interface to the JSP template or other
 * text that needs to be inserted.
 */

public class InsertTag extends TagSupport {

    private boolean directInclude = false;
    private String parameter = null;
    private Parameter parameterRef = null;
    private Screen screen = null;

    /**
     * default constructor
     */
    public InsertTag() {
        super();
    }

    public void setParameter(String parameter){
        this.parameter = parameter;
    }

    public int doStartTag() throws JspTagException {
         try{
             pageContext.getOut().flush();
         } catch (Exception e){
             // do nothing
         }
        // load the ScreenFlow
        try {
                screen = (Screen)pageContext.getRequest().getAttribute(WebKeys.CURRENT_SCREEN);
        } catch (NullPointerException e){
            throw new JspTagException("Error extracting Screen from session: " + e);
        }
        if ((screen != null) && (parameter != null)) {
            parameterRef = (Parameter)screen.getParameter(parameter);
        } else {
            System.err.println("InsertTag: screenManager is null");
        }
        if (parameterRef != null) directInclude = parameterRef.isDirect();
        return SKIP_BODY;
    }

    public int doEndTag() throws JspTagException {
        try {
            if (directInclude && parameterRef != null) {
                pageContext.getOut().print(parameterRef.getValue());
            } else if (parameterRef != null)  {
                if (parameterRef.getValue() != null) pageContext.getRequest().getRequestDispatcher(parameterRef.getValue()).include(pageContext.getRequest(), pageContext.getResponse());
            }
         } catch (Exception ex) {
             System.err.println("InsertTag:doEndTag caught: " + ex);
             ex.printStackTrace();
        }
        return EVAL_PAGE;
    }
}