welcomeaction.java

来自「Sample for struts mailreader」· Java 代码 · 共 85 行

/*
 * $Id: WelcomeAction.java 360442 2005-12-31 20:10:04Z husted $
 *
 * Copyright 2000-2004 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.apps.mailreader.actions;

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.apps.mailreader.Constants;
import org.apache.struts.apps.mailreader.dao.UserDatabase;
import org.apache.struts.util.MessageResources;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;


/**
 * <p>
 * Confirm required resources are available before displaying initial page.
 * </p><p>
 * If a resource is missing,
 * forward to "failure". Otherwise, forward to "success", where
 * success is usually the "welcome" page.
 * </p><p>
 * Since "required resources" includes the application MessageResources
 * the failure page must not use the standard error or message tags.
 * Instead, it display the Strings stored in an ArrayList stored under
 * the request attribute "ERROR".
 * </p>
 *
 * @version $Rev: 360442 $ $Date: 2005-12-31 13:10:04 -0700 (Sat, 31 Dec 2005) $
 */
public final class WelcomeAction extends BaseAction {

    // See superclass for Javadoc
    public ActionForward execute(
            ActionMapping mapping,
            ActionForm form,
            HttpServletRequest request,
            HttpServletResponse response)
            throws Exception {

        // Setup message array in case there are errors
        ArrayList messages = new ArrayList();

        // Confirm message resources loaded
        MessageResources resources = getResources(request);
        if (resources == null) {
            messages.add(Constants.ERROR_MESSAGES_NOT_LOADED);
        }

        // Confirm database loaded
        UserDatabase userDatabase = doGetUserDatabase();
        if (userDatabase == null) {
            messages.add(Constants.ERROR_DATABASE_NOT_LOADED);
        }

        // If there were errors, forward to our failure page
        if (messages.size() > 0) {
            request.setAttribute(Constants.ERROR_KEY, messages);
            return doFindFailure(mapping);
        }

        // Forward to our success page
        return doFindSuccess(mapping);

    }

}