/*
 * RHQ Management Platform
 * Copyright (C) 2005-2008 Red Hat, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.rhq.enterprise.gui.legacy.action;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.rhq.enterprise.gui.legacy.util.SessionUtils;

/**
 * This Action is designed to be part of a workflow, saving it's current return path in the workflow stack.
 */
public abstract class WorkflowAction extends BaseAction {
    /**
     * Starts workflow by taking what is currently stored in the session as returnPath (one of many possible origins of
     * this workflow), and pushing it onto our workflow stack. Passes call to workflow() so that the child class can
     * overload.
     */
    public final ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request,
        HttpServletResponse response) throws Exception {
        if (!(mapping instanceof BaseActionMapping)) {
            throw new ServletException("mapping " + mapping.getName() + "is not an instance of BaseActionMapping.");
        }

        BaseActionMapping smap = (BaseActionMapping) mapping;

        String workflowId = smap.getWorkflow();
        if ((workflowId == null) || "".equals(workflowId.trim())) {
            throw new ServletException("workflow " + smap.getName() + " has a null or invalid workflow attribute.");
        }

        // takes the current returnPath in the session and stores it
        // in the workflow.
        SessionUtils.pushWorkflow(request.getSession(false), mapping, workflowId);

        return workflow(mapping, form, request, response);
    }

    /**
     * To participate in a workflow, simply implement this the same as you would execute(). This will be called by
     * SpiderWorkfowActions's execute() method after it saves the workflow context.
     */
    public abstract ActionForward workflow(ActionMapping mapping, ActionForm form, HttpServletRequest request,
        HttpServletResponse response) throws Exception;
}