strutsutils.java

一个用于java web页面开发的开源包

package org.apache.velocity.tools.struts;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import java.util.Locale;
import java.util.Iterator;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts.Globals;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.config.ForwardConfig;
import org.apache.struts.config.ActionConfig;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;
import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.ModuleUtils;

/**
 * <p>A utility class to expose the Struts shared
 * resources. All methods are static.</p>
 *
 * <p>This class is provided for use by Velocity view tools
 * that need access to Struts resources. By having all Struts-
 * specific code in this utility class, maintenance is simplified
 * and reuse fostered.</p>
 *
 * <p>It is the aim, that sooner or later the functionality in
 * this class is integrated into Struts itself.  See
 * <a href="http://nagoya.apache.org/bugzilla/show_bug.cgi?id=16814">Bug #16814</a>
 * for more on that.</p>
 *
 * @author <a href="mailto:[e-mail]">Marino A. Jonsson</a>
 * @author Nathan Bubna
 * @author <a href="mailto:[e-mail]">Gabe Sidler</a>
 * based on code by <a href="mailto:[e-mail]">Ted Husted</a>
 *
 * @version $Id: StrutsUtils.java 479724 2006-11-27 18:49:37Z nbubna $
 */
public class StrutsUtils
{

    /****************** Struts ServletContext Resources ****************/

    /**
     * Returns the message resources for this application or <code>null</code>
     * if not found.
     *
     * @param app the servlet context
     * @since VelocityTools 1.1
     */
    public static MessageResources getMessageResources(HttpServletRequest request,
                                                       ServletContext app)
    {
        /* Identify the current module */
        ModuleConfig moduleConfig = ModuleUtils.getInstance().getModuleConfig(request, app);
        return (MessageResources)app.getAttribute(Globals.MESSAGES_KEY +
                                                  moduleConfig.getPrefix());
    }


    /**
     * Returns the message resources with the specified bundle name for this application
     * or <code>null</code> if not found.
     *
     * @param app the servlet context
     * @param bundle The bundle name to look for.  If this is <code>null</code>, the
     *               default bundle name is used.
     * @since VelocityTools 1.1
     */
    public static MessageResources getMessageResources(HttpServletRequest request,
                                                       ServletContext app,
                                                       String bundle)
    {
        MessageResources resources = null;

        /* Identify the current module */
        ModuleConfig moduleConfig = ModuleUtils.getInstance().getModuleConfig(request, app);


        if (bundle == null) {
            bundle = Globals.MESSAGES_KEY;
        }

        // First check request scope
        resources = (MessageResources) request.getAttribute(bundle + moduleConfig.getPrefix());

        if (resources == null) {
            resources = (MessageResources) app.getAttribute(bundle + moduleConfig.getPrefix());
        }

        return resources;
    }


    /**
     * Select the module to which the specified request belongs, and
     * add return the corresponding ModuleConfig.
     *
     * @param urlPath The requested URL
     * @param app The ServletContext for this web application
     * @return The ModuleConfig for the given URL path
     * @since VelocityTools 1.1
     */
    public static ModuleConfig selectModule(String urlPath,
                                            ServletContext app)
    {
        /* Match against the list of sub-application prefixes */
        String prefix = ModuleUtils.getInstance().getModuleName(urlPath, app);

        /* Expose the resources for this sub-application */
        ModuleConfig config = (ModuleConfig)
            app.getAttribute(Globals.MODULE_KEY + prefix);

        return config;
    }


    /********************** Struts Session Resources ******************/

    /**
     * Returns the <code>java.util.Locale</code> for the user. If a
     * locale object is not found in the user's session, the system
     * default locale is returned.
     *
     * @param request the servlet request
     * @param session the HTTP session
     */
    public static Locale getLocale(HttpServletRequest request,
                                   HttpSession session)
    {
        Locale locale = null;

        if (session != null)
        {
            locale = (Locale)session.getAttribute(Globals.LOCALE_KEY);
        }
        if (locale == null)
        {
            locale = request.getLocale();
        }
        return locale;
    }


    /**
     * Returns the transaction token stored in this session or
     * <code>null</code> if not used.
     *
     * @param session the HTTP session
     */
    public static String getToken(HttpSession session)
    {
        if (session == null)
        {
            return null;
        }
        return (String)session.getAttribute(Globals.TRANSACTION_TOKEN_KEY);
    }


    /*********************** Struts Request Resources ****************/

    /**
     * Returns the Struts errors for this request or <code>null</code>
     * if none exist. Since VelocityTools 1.2, this will also check
     * the session (if there is one) for errors if there are no errors
     * in the request.
     *
     * @param request the servlet request
     * @since VelocityTools 1.1
     */
    public static ActionMessages getErrors(HttpServletRequest request)
    {
        ActionMessages errors = (ActionMessages)request.getAttribute(Globals.ERROR_KEY);
        if (errors == null || errors.isEmpty())
        {
            // then check the session
            HttpSession session = request.getSession(false);
            if (session != null)
            {
                errors = (ActionMessages)session.getAttribute(Globals.ERROR_KEY);
            }
        }
        return errors;
    }

    /**
     * Returns the Struts messages for this request or <code>null</code>
     * if none exist.  Since VelocityTools 1.2, this will also check
     * the session (if there is one) for messages if there are no messages
     * in the request.
     *
     * @param request the servlet request
     * @since VelocityTools 1.1
     */
    public static ActionMessages getMessages(HttpServletRequest request)
    {
        ActionMessages messages = (ActionMessages)request.getAttribute(Globals.MESSAGE_KEY);
        if (messages == null || messages.isEmpty())
        {
            // then check the session
            HttpSession session = request.getSession(false);
            if (session != null)
            {
                messages = (ActionMessages)session.getAttribute(Globals.MESSAGE_KEY);
            }
        }
        return messages;
    }

    /**
     * Returns the <code>ActionForm</code> bean associated with
     * this request of <code>null</code> if none exists.
     *
     * @param request the servlet request
     * @param session the HTTP session
     */
    public static ActionForm getActionForm(HttpServletRequest request,
                                           HttpSession session)
    {
        /* Is there a mapping associated with this request? */
        ActionConfig mapping =
            (ActionConfig)request.getAttribute(Globals.MAPPING_KEY);
        if (mapping == null)
        {
            return null;
        }

        /* Is there a form bean associated with this mapping? */
        String attribute = mapping.getAttribute();
        if (attribute == null)
        {
            return null;
        }

        /* Look up the existing form bean */
        if ("request".equals(mapping.getScope()))
        {
            return (ActionForm)request.getAttribute(attribute);
        }
        if (session != null)
        {
            return (ActionForm)session.getAttribute(attribute);
        }
        return null;
    }

    /**
     * Returns the ActionForm name associated with
     * this request of <code>null</code> if none exists.
     *
     * @param request the servlet request
     * @param session the HTTP session
     */
    public static String getActionFormName(HttpServletRequest request,
                                           HttpSession session)
    {
        /* Is there a mapping associated with this request? */
        ActionConfig mapping =
            (ActionConfig)request.getAttribute(Globals.MAPPING_KEY);
        if (mapping == null)