/*
    * $Id: ServletApplicationContext.java 1297705 2012-03-06 20:44:30Z nlebas $
    *
    * 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.tiles.request.servlet;
  
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Locale;
  import java.util.Map;
  
  import javax.servlet.ServletContext;
  
  import org.apache.tiles.request.ApplicationContext;
  import org.apache.tiles.request.ApplicationResource;
  import org.apache.tiles.request.collection.ReadOnlyEnumerationMap;
  import org.apache.tiles.request.collection.ScopeMap;
  import org.apache.tiles.request.locale.URLApplicationResource;
  import org.apache.tiles.request.servlet.extractor.ApplicationScopeExtractor;
  import org.apache.tiles.request.servlet.extractor.InitParameterExtractor;
  
  /**
   * Servlet-based implementation of the TilesApplicationContext interface.
   *
   * @version $Rev: 1297705 $ $Date: 2012-03-07 07:44:30 +1100 (Wed, 07 Mar 2012) $
   */
  public class ServletApplicationContext implements ApplicationContext {
  
      /**
       * The servlet context to use.
       */
      private ServletContext servletContext;
  
      /**
       * <p>The lazily instantiated <code>Map</code> of application scope
       * attributes.</p>
       */
      private Map<String, Object> applicationScope = null;
  
      /**
       * <p>The lazily instantiated <code>Map</code> of context initialization
       * parameters.</p>
       */
      private Map<String, String> initParam = null;
  
      /**
       * Creates a new instance of ServletTilesApplicationContext.
       *
       * @param servletContext The servlet context to use.
       */
      public ServletApplicationContext(ServletContext servletContext) {
          this.servletContext = servletContext;
      }
  
      /** {@inheritDoc} */
      public Object getContext() {
          return servletContext;
      }
  
      /** {@inheritDoc} */
      public Map<String, Object> getApplicationScope() {
  
          if ((applicationScope == null) && (servletContext != null)) {
              applicationScope = new ScopeMap(new ApplicationScopeExtractor(servletContext));
          }
          return (applicationScope);
  
      }
  
      /** {@inheritDoc} */
      public Map<String, String> getInitParams() {
  
          if ((initParam == null) && (servletContext != null)) {
              initParam = new ReadOnlyEnumerationMap<String>(new InitParameterExtractor(servletContext));
          }
          return (initParam);
  
      }
  
      /** {@inheritDoc} */
      public ApplicationResource getResource(String localePath) {
         try {
             URL url = servletContext.getResource(localePath);
             if (url != null) {
                 return new URLApplicationResource(localePath, url);
             } else {
                 return null;
             }
         } catch (MalformedURLException e) {
             return null;
         }
     }
 
     /** {@inheritDoc} */
     public ApplicationResource getResource(ApplicationResource base, Locale locale) {
         try {
             URL url = servletContext.getResource(base.getLocalePath(locale));
             if (url != null) {
                 return new URLApplicationResource(base.getPath(), locale, url);
             } else {
                 return null;
             }
         } catch (MalformedURLException e) {
             return null;
         }
     }
 
     /** {@inheritDoc} */
     public Collection<ApplicationResource> getResources(String path) {
         ArrayList<ApplicationResource> resources = new ArrayList<ApplicationResource>();
         resources.add(getResource(path));
         return resources;
     }
 }