confighelper.java.svn-base

MVC开源框架

/*
 * $Id$
 *
 * 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.
 */
package org.apache.struts.config;

import org.apache.struts.Globals;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionFormBean;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.upload.MultipartRequestWrapper;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;

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

/**
 * <p> NOTE: THIS CLASS IS UNDER ACTIVE DEVELOPMENT. THE CURRENT CODE IS
 * WRITTEN FOR CLARITY NOT EFFICIENCY. NOT EVERY API FUNCTION HAS BEEN
 * IMPLEMENTED YET. </p><p> A helper object to expose the Struts shared
 * resources, which are be stored in the application, session, or request
 * contexts, as appropriate. </p><p> An instance should be created for each
 * request processed. The  methods which return resources from the request or
 * session contexts are not thread-safe. </p><p> Provided for use by other
 * servlets in the application so they can easily access the Struts shared
 * resources. </p><p> The resources are stored under attributes in the
 * application, session, or request contexts. </p><p> The ActionConfig methods
 * simply return the resources from under the context and key used by the
 * Struts ActionServlet when the resources are created. </p>
 *
 * @version $Rev$ $Date: 2005-05-14 02:09:06 -0400 (Sat, 14 May 2005)
 *          $
 * @since Struts 1.1
 */
public class ConfigHelper implements ConfigHelperInterface {
    // --------------------------------------------------------  Properites

    /**
     * <p> The application associated with this instance. </p>
     */
    private ServletContext application = null;

    /**
     * <p> The session associated with this instance. </p>
     */
    private HttpSession session = null;

    /**
     * <p> The request associated with this instance. </p>
     */
    private HttpServletRequest request = null;

    /**
     * <p> The response associated with this instance. </p>
     */
    private HttpServletResponse response = null;

    /**
     * <p> The forward associated with this instance. </p>
     */
    private ActionForward forward = null;

    public ConfigHelper() {
        super();
    }

    public ConfigHelper(ServletContext application, HttpServletRequest request,
        HttpServletResponse response) {
        super();
        this.setResources(application, request, response);
    }

    /**
     * <p> Set the application associated with this instance.
     * [servlet.getServletContext()] </p>
     */
    public void setApplication(ServletContext application) {
        this.application = application;
    }

    /**
     * <p> Set the session associated with this instance. </p>
     */
    public void setSession(HttpSession session) {
        this.session = session;
    }

    /**
     * <p> Set the request associated with this object. Session object is also
     * set or cleared. </p>
     */
    public void setRequest(HttpServletRequest request) {
        this.request = request;

        if (this.request == null) {
            setSession(null);
        } else {
            setSession(this.request.getSession());
        }
    }

    /**
     * <p> Set the response associated with this isntance. Session object is
     * also set or cleared. </p>
     */
    public void setResponse(HttpServletResponse response) {
        this.response = response;
    }

    /**
     * Set the forward associated with this instance.
     */
    public void setForward(ActionForward forward) {
        this.forward = forward;
    }

    /**
     * <p> Set the application and request for this object instance. The
     * ServletContext can be set by any servlet in the application. The
     * request should be the instant request. Most of the other methods
     * retrieve their own objects by reference to the application, request, or
     * session attributes. Do not call other methods without setting these
     * first! This is also called by the convenience constructor. </p>
     *
     * @param application - The associated ServletContext.
     * @param request     - The associated HTTP request.
     * @param response    - The associated HTTP response.
     */
    public void setResources(ServletContext application,
        HttpServletRequest request, HttpServletResponse response) {
        setApplication(application);
        setRequest(request);
        setResponse(response);
    }

    // ------------------------------------------------ Application Context
    public ActionMessages getActionMessages() {
        if (this.application == null) {
            return null;
        }

        return (ActionMessages) this.application.getAttribute(Globals.MESSAGE_KEY);
    }

    /**
     * <p> The application resources for this application. </p>
     */
    public MessageResources getMessageResources() {
        if (this.application == null) {
            return null;
        }

        return (MessageResources) this.application.getAttribute(Globals.MESSAGES_KEY);
    }

    /**
     * <p> The path-mapped pattern (<code>/action/*</code>) or extension
     * mapped pattern ((<code>*.do</code>) used to determine our Action URIs
     * in this application. </p>
     */
    public String getServletMapping() {
        if (this.application == null) {
            return null;
        }

        return (String) this.application.getAttribute(Globals.SERVLET_KEY);
    }

    // ---------------------------------------------------- Session Context

    /**
     * <p> The transaction token stored in this session, if it is used. </p>
     */
    public String getToken() {
        if (this.session == null) {
            return null;
        }

        return (String) session.getAttribute(Globals.TRANSACTION_TOKEN_KEY);
    }

    // ---------------------------------------------------- Request Context

    /**
     * <p> The runtime JspException that may be been thrown by a Struts tag
     * extension, or compatible presentation extension, and placed in the
     * request. </p>
     */
    public Throwable getException() {
        if (this.request == null) {
            return null;
        }

        return (Throwable) this.request.getAttribute(Globals.EXCEPTION_KEY);
    }

    /**
     * <p> The multipart object for this request. </p>
     */
    public MultipartRequestWrapper getMultipartRequestWrapper() {
        if (this.request == null) {
            return null;
        }

        return (MultipartRequestWrapper) this.request.getAttribute(Globals.MULTIPART_KEY);
    }

    /**
     * <p> The <code>org.apache.struts.ActionMapping</code> instance for this
     * request. </p>
     */
    public ActionMapping getMapping() {
        if (this.request == null) {
            return null;
        }

        return (ActionMapping) this.request.getAttribute(Globals.MAPPING_KEY);
    }

    // ---------------------------------------------------- Utility Methods

    /**
     * <p> Return true if a message string for the specified message key is
     * present for the user's Locale. </p>
     *
     * @param key Message key
     */
    public boolean isMessage(String key) {
        // Look up the requested MessageResources
        MessageResources resources = getMessageResources();

        if (resources == null) {
            return false;
        }

        // Return the requested message presence indicator
        return resources.isPresent(RequestUtils.getUserLocale(request, null),
            key);
    }

    /*
     * <p>
     * Retrieve and return the <code>ActionForm</code> bean associated with
     * this mapping, creating and stashing one if necessary.  If there is no
     * form bean associated with this mapping, return <code>null</code>.
     * </p>
     */
    public ActionForm getActionForm() {
        // Is there a mapping associated with this request?
        ActionMapping mapping = getMapping();

        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 any
        ActionForm instance;

        if ("request".equals(mapping.getScope())) {
            instance = (ActionForm) this.request.getAttribute(attribute);
        } else {
            instance = (ActionForm) this.session.getAttribute(attribute);