checklogontag.java

jakarta-struts-1.2.4-src

/*
 * Copyright 1999-2001,2004 The Apache Software Foundation.
 * 
 * Licensed 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.struts.webapp.example;


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


/**
 * Check for a valid User logged on in the current session.  If there is no
 * such user, forward control to the logon page.
 *
 * @author Craig R. McClanahan
 * @author Marius Barduta
 * @version $Revision: 1.3 $ $Date: 2004/03/08 02:49:52 $
 */

public final class CheckLogonTag extends TagSupport {


    // --------------------------------------------------- Instance Variables


    /**
     * The key of the session-scope bean we look for.
     */
    private String name = Constants.USER_KEY;


    /**
     * The page to which we should forward for the user to log on.
     */
    private String page = "/logon.jsp";


    // ----------------------------------------------------------- Properties


    /**
     * Return the bean name.
     */
    public String getName() {

	return (this.name);

    }


    /**
     * Set the bean name.
     *
     * @param name The new bean name
     */
    public void setName(String name) {

	this.name = name;

    }


    /**
     * Return the forward page.
     */
    public String getPage() {

	return (this.page);

    }


    /**
     * Set the forward page.
     *
     * @param page The new forward page
     */
    public void setPage(String page) {

	this.page = page;

    }


    // ------------------------------------------------------- Public Methods


    /**
     * Defer our checking until the end of this tag is encountered.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

	return (SKIP_BODY);

    }


    /**
     * Perform our logged-in user check by looking for the existence of
     * a session scope bean under the specified name.  If this bean is not
     * present, control is forwarded to the specified logon page.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {

	// Is there a valid user logged on?
	boolean valid = false;
	HttpSession session = pageContext.getSession();
	if ((session != null) && (session.getAttribute(name) != null))
	    valid = true;

	// Forward control based on the results
	if (valid)
	    return (EVAL_PAGE);
	else {
	    try {
		pageContext.forward(page);
	    } catch (Exception e) {
		throw new JspException(e.toString());
	    }
	    return (SKIP_PAGE);
	}

    }


    /**
     * Release any acquired resources.
     */
    public void release() {

        super.release();
        this.name = Constants.USER_KEY;
        this.page = "/logon.jsp";

    }


}