/*
    * Copyright (c) 2002-2014, Mairie de Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.portal.service.resource;
  
  import fr.paris.lutece.portal.service.cache.AbstractCacheableService;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import java.util.StringTokenizer;
  
  
  /**
   * This abstract Class provides a standard way for application to deliver resources
   * using multiple loaders and an optional cache.
   * @since v1.4.1
   */
  public abstract class ResourceService extends AbstractCacheableService
  {
      // Constants
      private static final String DELIMITER = ",";
      private static final String UNDEFINED_SERVICE_NAME = "Undefined Service Name";
  
      // Variables
      private String _strName = UNDEFINED_SERVICE_NAME;
      private List<ResourceLoader> _listLoaders = new ArrayList<ResourceLoader>(  );
  
      /**
       *
       */
      protected ResourceService(  )
      {
          String strLoadersProperty = getLoadersProperty(  );
  
          if ( ( strLoadersProperty != null ) && ( !strLoadersProperty.equals( "" ) ) )
          {
              initLoaders( strLoadersProperty );
  
              //            initCache( getName() );
          }
          else
          {
              AppLogService.error( "Resource service : Loaders property key is missing" );
          }
      }
  
      // Methods to overide
      /**
       * Gets the name of the property that list all loaders
       * @return The property key
       */
      protected abstract String getLoadersProperty(  );
  
      /**
       * Initialize loaders
       * @param strKey The property key that contains all loaders class
       */
      protected void initLoaders( String strKey )
      {
          String strLoaders = AppPropertiesService.getProperty( strKey );
          StringTokenizer st = new StringTokenizer( strLoaders, DELIMITER );
  
          while ( st.hasMoreTokens(  ) )
          {
              String strLoaderClassName = st.nextToken(  );
             addLoader( strLoaderClassName );
         }
     }
 
     /**
      * Set the service name
      * @param strName The service name
      */
     protected void setName( String strName )
     {
         _strName = strName;
     }
 
     /**
      * Get the service name
      * @return The service name
      */
     public String getName(  )
     {
         return _strName;
     }
 
     /**
      * Set the service name by reading a property
      * @param strKey The name key
      */
     protected void setNameKey( String strKey )
     {
         setName( AppPropertiesService.getProperty( strKey, UNDEFINED_SERVICE_NAME ) );
     }
 
     /**
      * Defines whether the cache is enable or disable reading a property
      * @param strKey The key name of the cache
      */
     protected void setCacheKey( String strKey )
     {
         String strCache = AppPropertiesService.getProperty( strKey, "false" );
 
         if ( strCache.equals( "true" ) )
         {
             initCache( getName(  ) );
         }
     }
 
     /**
      * Add a new loader to the service
      * @param strLoaderClassName The loader class name
      */
     protected void addLoader( String strLoaderClassName )
     {
         try
         {
             ResourceLoader loader = (ResourceLoader) Class.forName( strLoaderClassName ).newInstance(  );
             _listLoaders.add( loader );
         }
         catch ( IllegalAccessException e )
         {
             AppLogService.error( e.getMessage(  ), e );
         }
         catch ( InstantiationException e )
         {
             AppLogService.error( e.getMessage(  ), e );
         }
         catch ( ClassNotFoundException e )
         {
             AppLogService.error( e.getMessage(  ), e );
         }
     }
 
     /**
      * Returns a resource by its Id
      * @param strId The resource Id
      * @return A resource
      */
     protected Resource getResource( String strId )
     {
         Resource resource = null;
 
         if ( isCacheEnable(  ) )
         {
             resource = (Resource) getFromCache( strId );
 
             if ( resource == null )
             {
                 resource = loadResource( strId );
 
                 if ( resource != null )
                 {
                     putInCache( strId, resource );
                 }
             }
         }
         else
         {
             resource = loadResource( strId );
         }
 
         return resource;
     }
 
     /**
      * Load a resource by its Id
      * @param strId The resource Id
      * @return A resource
      */
     private Resource loadResource( String strId )
     {
         Resource resource = null;
         Iterator<ResourceLoader> i = _listLoaders.iterator(  );
 
         while ( i.hasNext(  ) && ( resource == null ) )
         {
             ResourceLoader loader = (ResourceLoader) i.next(  );
             resource = loader.getResource( strId );
         }
 
         return resource;
     }
 
     /**
      * Load all resources
      * @return A collection of resources
      */
     protected Collection<Resource> getResources(  )
     {
         List<Resource> listResources = new ArrayList<Resource>(  );
         Iterator<ResourceLoader> i = _listLoaders.iterator(  );
 
         while ( i.hasNext(  ) )
         {
             ResourceLoader loader = (ResourceLoader) i.next(  );
             Collection<Resource> colResources = loader.getResources(  );
             Iterator<Resource> j = colResources.iterator(  );
 
             while ( j.hasNext(  ) )
             {
                 Resource resource = (Resource) j.next(  );
                 listResources.add( resource );
             }
         }
 
         return listResources;
     }
 }