/*
 * $Id: ForwardTag.java 54929 2004-10-16 16:38:42Z germuska $ 
 *
 * Copyright 1999-2004 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.taglib.logic;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.struts.action.ActionForward;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;

/**
 * Perform a forward or redirect to a page that is looked up in the
 * configuration information associated with our application.
 *
 * @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
 */
public class ForwardTag extends TagSupport {

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

    /**
     * The message resources for this package.
     */
    protected static MessageResources messages =
        MessageResources.getMessageResources(
            "org.apache.struts.taglib.logic.LocalStrings");

    /**
     * The logical name of the <code>ActionForward</code> entry to be
     * looked up.
     */
    protected String name = null;

    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        this.name = name;
    }

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

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

        return (SKIP_BODY);

    }

    /**
     * Look up the ActionForward associated with the specified name,
     * and perform a forward or redirect to that path as indicated.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {

        // Look up the desired ActionForward entry
        ActionForward forward = null;
        ModuleConfig config = TagUtils.getInstance().getModuleConfig(pageContext);
        
        if (config != null){
            forward = (ActionForward) config.findForwardConfig(name);
        }
            
        if (forward == null) {
            JspException e =
                new JspException(messages.getMessage("forward.lookup", name));
            TagUtils.getInstance().saveException(pageContext, e);
            throw e;
        }

        // Forward or redirect to the corresponding actual path
        String path = forward.getPath();
        path = config.getPrefix() + path;

        if (forward.getRedirect()) {
            this.doRedirect(path);
        } else {
            this.doForward(path);
        }

        // Skip the remainder of this page
        return (SKIP_PAGE);

    }

    /**
     * Forward to the given path converting exceptions to JspException.
     * @param path The path to forward to.
     * @throws JspException
     * @since Struts 1.2
     */
    protected void doForward(String path) throws JspException {
        try {
            pageContext.forward(path);
            
        } catch (Exception e) {
            TagUtils.getInstance().saveException(pageContext, e);
            throw new JspException(
                messages.getMessage("forward.forward", name, e.toString()));
        }
    }

    /**
     * Redirect to the given path converting exceptions to JspException.
     * @param path The path to redirect to.
     * @throws JspException
     * @since Struts 1.2
     */
    protected void doRedirect(String path) throws JspException {
        HttpServletRequest request =
            (HttpServletRequest) pageContext.getRequest();
            
        HttpServletResponse response =
            (HttpServletResponse) pageContext.getResponse();
            
        try {
            if (path.startsWith("/")) {
                path = request.getContextPath() + path;
            }
            
            response.sendRedirect(response.encodeRedirectURL(path));
            
        } catch (Exception e) {
            TagUtils.getInstance().saveException(pageContext, e);
            throw new JspException(
                messages.getMessage("forward.redirect", name, e.toString()));
        }
    }

    /**
     * Release all allocated resources.
     */
    public void release() {

        super.release();
        name = null;

    }

}