/*
 * Copyright 2001-2002,2004 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.webapp.admin.host;

import java.io.IOException;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Arrays;
import java.util.Locale;
import java.util.TreeSet;
import java.util.Set;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.QueryExp;
import javax.management.Query;
import javax.management.ObjectInstance;
import javax.management.ObjectName;
import javax.management.JMException;
import org.apache.struts.util.MessageResources;

import org.apache.webapp.admin.ApplicationServlet;
import org.apache.webapp.admin.TomcatTreeBuilder;

/**
 * The <code>Action</code> that sets up <em>Delete Aliases</em> transactions.
 *
 * @author Manveen Kaur
 * @version $Revision$ $Date$
 */

public class DeleteAliasAction extends Action {
    

    /**
     * The MBeanServer we will be interacting with.
     */
    private MBeanServer mBServer = null;
    

    // --------------------------------------------------------- Public Methods
    
    /**
     * Process the specified HTTP request, and create the corresponding HTTP
     * response (or forward to another web component that will create it).
     * Return an <code>ActionForward</code> instance describing where and how
     * control should be forwarded, or <code>null</code> if the response has
     * already been completed.
     *
     * @param mapping The ActionMapping used to select this instance
     * @param actionForm The optional ActionForm bean for this request (if any)
     * @param request The HTTP request we are processing
     * @param response The HTTP response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet exception occurs
     */
    public ActionForward perform(ActionMapping mapping,
                                 ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response)
        throws IOException, ServletException {
        

        // Acquire the resources that we need
        HttpSession session = request.getSession();
        Locale locale = getLocale(request);
        MessageResources resources = getResources(request);
        
        // Acquire a reference to the MBeanServer containing our MBeans
        try {
            mBServer = ((ApplicationServlet) getServlet()).getServer();
        } catch (Throwable t) {
            throw new ServletException
            ("Cannot acquire MBeanServer reference", t);
        }
        
        // Set up a form bean containing the currently selected
        // objects to be deleted
        AliasesForm aliasesFm = new AliasesForm();
        ArrayList aliasesList = null;
        
        String hostName = request.getParameter("hostName");
        aliasesFm.setHostName(hostName);
        
        // retrieve all aliases
        String operation = null;
        try {
            ObjectName hname = new ObjectName(hostName);

            operation = "findAliases";
            String aliases[] = 
                (String[]) mBServer.invoke(hname, operation, null, null);
            aliasesFm.setAliases(aliases);
            aliasesList = new ArrayList(Arrays.asList(aliases));

        } catch (Throwable t) {
            getServlet().log
            (resources.getMessage(locale, "users.error.invoke",
                                  operation), t);
            response.sendError
                (HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                resources.getMessage(locale, "users.error.invoke",
                                     operation));
            return (null);            
        }
                
        Collections.sort(aliasesList);        
        request.setAttribute("aliasesForm", aliasesFm);        
        request.setAttribute("aliasesList", aliasesList);
        
        // Forward to the list display page
        return (mapping.findForward("Aliases"));

    }

}