/*
    * 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.myfaces.spi;
  
  import java.util.List;
  import java.util.Map;
  import java.util.ServiceLoader;
  import javax.faces.FactoryFinder;
  import javax.faces.context.ExternalContext;
  
  /**
   * This class provides an interface to override SPI handling done by
   * MyFaces.
   * 
   * This is useful on environments like in OSGi, because it allows to
   * put custom code to find SPI interfaces under META-INF/services/
   * 
   * @author Leonardo Uribe
   * @since 2.0.3
   *
   */
  public abstract class ServiceProviderFinder
  {
      public static final String[] KNOWN_SERVICES = 
      {
          FactoryFinder.APPLICATION_FACTORY,
          FactoryFinder.CLIENT_WINDOW_FACTORY,
          FactoryFinder.EXCEPTION_HANDLER_FACTORY,
          FactoryFinder.EXTERNAL_CONTEXT_FACTORY,
          FactoryFinder.FACELET_CACHE_FACTORY,
          FactoryFinder.FACES_CONTEXT_FACTORY,
          FactoryFinder.FLASH_FACTORY,
          FactoryFinder.FLOW_HANDLER_FACTORY,
          FactoryFinder.LIFECYCLE_FACTORY,
          FactoryFinder.PARTIAL_VIEW_CONTEXT_FACTORY,
          FactoryFinder.RENDER_KIT_FACTORY,
          FactoryFinder.TAG_HANDLER_DELEGATE_FACTORY,
          FactoryFinder.VIEW_DECLARATION_LANGUAGE_FACTORY,
          FactoryFinder.VISIT_CONTEXT_FACTORY,
          FactoryFinder.SEARCH_EXPRESSION_CONTEXT_FACTORY,
          "org.apache.myfaces.spi.AnnotationProvider",
          "org.apache.myfaces.spi.AnnotationProviderFactory",
          "org.apache.myfaces.spi.FaceletConfigResourceProvider",
          "org.apache.myfaces.spi.FaceletConfigResourceProviderFactory",
          "org.apache.myfaces.spi.FacesConfigResourceProvider",
          "org.apache.myfaces.spi.FacesConfigResourceProviderFactory",
          "org.apache.myfaces.spi.FacesConfigurationMerger",
          "org.apache.myfaces.spi.FacesConfigurationMergerFactory",
          "org.apache.myfaces.spi.FacesConfigurationProvider",
          "org.apache.myfaces.spi.FacesConfigurationProviderFactory",
          "org.apache.myfaces.spi.FacesFlowProvider",
          "org.apache.myfaces.spi.FacesFlowProviderFactory",
          "org.apache.myfaces.spi.FactoryFinderProvider",
          "org.apache.myfaces.spi.FactoryFinderProviderFactory",
          "org.apache.myfaces.spi.InjectionProvider",
          "org.apache.myfaces.spi.InjectionProviderFactory",
          "org.apache.myfaces.spi.ResourceLibraryContractsProvider",
          "org.apache.myfaces.spi.ResourceLibraryContractsProviderFactory",
          "org.apache.myfaces.spi.ViewScopeProvider",
          "org.apache.myfaces.spi.ViewScopeProviderFactory",
          "org.apache.myfaces.spi.WebConfigProvider",
          "org.apache.myfaces.spi.WebConfigProviderFactory",
          "org.apache.myfaces.config.annotation.LifecycleProvider",
          "org.apache.myfaces.config.annotation.LifecycleProviderFactory",
      };
      
      /**
       * Gets the list of classes bound to the spiClass key, looking
       * for entries under META-INF/services/[spiClass]
       * 
       * @param spiClass
       * @return
       */
      public abstract List<String> getServiceProviderList(String spiClass);
      
      public <S> ServiceLoader<S> load(Class<S> spiClass)
      {
          return ServiceLoader.load(spiClass);
      }
      
      /**
       * If ServiceProviderFinderFactory knows beforehand or has stored somewhere the
       * known locations of the SPI interfaces, this method helps to set this config
      * information so the implementation of this interface can use it. The idea is
      * MyFaces initialization algorithm will call getKnownServiceProviderMapInfo
      * method and if the value is not null it will call this method to pass the
      * map back to the ServiceProviderFinder, so it can take it.
      * 
      * @param map 
      */
     public void initKnownServiceProviderMapInfo(ExternalContext ectx, Map<String, List<String>> map)
     {
     }
 
     public Map<String, List<String>> calculateKnownServiceProviderMapInfo(ExternalContext ectx, 
         String[] knownServices)
     {
         //Map<String, List<String>> map = new HashMap<String, List<String>>();
         //for (String service : knownServices)
         //{
         //    map.put(service, this.getServiceProviderList(service));
         //}
         //return map;
         return null;
     }
 }