/*
    * $Id: ConfigHelper.java 471754 2006-11-06 14:55:09Z husted $
    *
    * 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: 471754 $ $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);
         }
 
         return instance;
     }
 
     /**
      * <p> Return the form bean definition associated with the specified
      * logical name, if any; otherwise return <code>null</code>. </p>
      *
      * @param name Logical name of the requested form bean definition
      */
     public ActionFormBean getFormBean(String name) {
         return null;
     }
 
     /**
      * <p> Return the forwarding associated with the specified logical name,
      * if any; otherwise return <code>null</code>. </p>
      *
      * @param name Logical name of the requested forwarding
      */
     public ActionForward getActionForward(String name) {
         return null;
     }
 
     /**
      * <p> Return the mapping associated with the specified request path, if
      * any; otherwise return <code>null</code>. </p>
      *
      * @param path Request path for which a mapping is requested
      */
     public ActionMapping getActionMapping(String path) {
         return null;
     }
 
     /**
      * <p> Return the form action converted into an action mapping path.  The
      * value of the <code>action</code> property is manipulated as follows in
      * computing the name of the requested mapping:</p>
      *
      * <ul>
      *
      * <li>Any filename extension is removed (on the theory that extension
      * mapping is being used to select the controller servlet).</li>
      *
      * <li>If the resulting value does not start with a slash, then a slash is
      * prepended.</li>
      *
      * </ul>
      */
     public String getActionMappingName(String action) {
         String value = action;
         int question = action.indexOf("?");
 
         if (question >= 0) {
             value = value.substring(0, question);
         }
 
         int slash = value.lastIndexOf("/");
         int period = value.lastIndexOf(".");
 
         if ((period >= 0) && (period > slash)) {
             value = value.substring(0, period);
         }
 
         if (value.startsWith("/")) {
             return (value);
         } else {
             return ("/" + value);
         }
     }
 
     /**
      * <p> Return the form action converted into a server-relative URL. </p>
      */
     public String getActionMappingURL(String action) {
         StringBuffer value = new StringBuffer(this.request.getContextPath());
 
         // Use our servlet mapping, if one is specified
         String servletMapping = getServletMapping();
 
         if (servletMapping != null) {
             String queryString = null;
             int question = action.indexOf("?");
 
             if (question >= 0) {
                 queryString = action.substring(question);
             }
 
             String actionMapping = getActionMappingName(action);
 
             if (servletMapping.startsWith("*.")) {
                 value.append(actionMapping);
                 value.append(servletMapping.substring(1));
             } else if (servletMapping.endsWith("/*")) {
                 value.append(servletMapping.substring(0,
                         servletMapping.length() - 2));
                 value.append(actionMapping);
             }
 
             if (queryString != null) {
                 value.append(queryString);
             }
         }
         // Otherwise, assume extension mapping is in use and extension is
         // already included in the action property
         else {
             if (!action.startsWith("/")) {
                 value.append("/");
             }
 
             value.append(action);
         }
 
         // Return the completed value
         return (value.toString());
     }
 
     /**
      * <p> Return the url encoded to maintain the user session, if any. </p>
      */
     public String getEncodeURL(String url) {
         if ((session != null) && (response != null)) {
             boolean redirect = false;
 
             if (forward != null) {
                 redirect = forward.getRedirect();
             }
 
             if (redirect) {
                 return response.encodeRedirectURL(url);
             } else {
                 return response.encodeURL(url);
             }
         } else {
             return (url);
         }
     }
 
     // ------------------------------------------------ Presentation API
 
     /**
      * <p> Renders the reference for a HTML <base> element </p>
      */
     public String getOrigRef() {
         // HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
         if (request == null) {
             return null;
         }
 
         StringBuffer result =
             RequestUtils.requestToServerUriStringBuffer(request);
 
         return result.toString();
     }
 
     /**
      * <p> Renders the reference for a HTML <base> element. </p>
      */
     public String getBaseRef() {
         if (request == null) {
             return null;
         }
 
         StringBuffer result = RequestUtils.requestToServerStringBuffer(request);
         String path;
 
         if (forward == null) {
             path = request.getRequestURI();
         } else {
             path = request.getContextPath() + forward.getPath();
         }
 
         result.append(path);
 
         return result.toString();
     }
 
     /**
      * <p> Return the path for the specified forward, otherwise return
      * <code>null</code>. </p>
      *
      * @param name Name given to local or global forward.
      */
     public String getLink(String name) {
         ActionForward forward = getActionForward(name);
 
         if (forward == null) {
             return null;
         }
 
         StringBuffer path = new StringBuffer(this.request.getContextPath());
 
         path.append(forward.getPath());
 
         // :TODO: What about runtime parameters?
         return getEncodeURL(path.toString());
     }
 
     /**
      * <p> Return the localized message for the specified key, otherwise
      * return <code>null</code>. </p>
      *
      * @param key Message key
      */
     public String getMessage(String key) {
         MessageResources resources = getMessageResources();
 
         if (resources == null) {
             return null;
         }
 
         return resources.getMessage(RequestUtils.getUserLocale(request, null),
             key);
     }
 
     /**
      * <p> Look up and return a message string, based on the specified
      * parameters. </p>
      *
      * @param key  Message key to be looked up and returned
      * @param args Replacement parameters for this message
      */
     public String getMessage(String key, Object[] args) {
         MessageResources resources = getMessageResources();
 
         if (resources == null) {
             return null;
         }
 
         // Return the requested message
         if (args == null) {
             return resources.getMessage(RequestUtils.getUserLocale(request, null),
                 key);
         } else {
             return resources.getMessage(RequestUtils.getUserLocale(request, null),
                 key, args);
         }
     }
 
     /**
      * <p> Return the URL for the specified ActionMapping, otherwise return
      * <code>null</code>. </p>
      *
      * @param path Name given to local or global forward.
      */
     public String getAction(String path) {
         return getEncodeURL(getActionMappingURL(path));
     }
 
     // --------------------------------------------- Presentation Wrappers
 
     /**
      * <p> Wrapper for getLink(String) </p>
      *
      * @param name Name given to local or global forward.
      */
     public String link(String name) {
         return getLink(name);
     }
 
     /**
      * <p> Wrapper for getMessage(String) </p>
      *
      * @param key Message key
      */
     public String message(String key) {
         return getMessage(key);
     }
 
     /**
      * <p> Wrapper for getMessage(String,Object[]) </p>
      *
      * @param key  Message key to be looked up and returned
      * @param args Replacement parameters for this message
      */
     public String message(String key, Object[] args) {
         return getMessage(key, args);
     }
 
     /**
      * <p> Wrapper for getAction(String) </p>
      *
      * @param path Name given to local or global forward.
      */
     public String action(String path) {
         return getAction(path);
     }
 }