/*
    * 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.onami.factoryannotation;
  
  import java.lang.annotation.Annotation;
  import java.util.HashMap;
  import java.util.Map;
  
  import com.google.inject.Key;
  import com.google.inject.TypeLiteral;
  
  class ProvisionCacheIdentityProviderFacade<T, A extends Annotation>
      implements FactoryAnnotationProvider<T, A>
  {
  
      private final Map<Key<T>, T> provisionCache = new HashMap<Key<T>, T>();
  
      private final FactoryAnnotationProvider<T, A> factoryAnnotationProvider;
  
      private final TypeLiteral<T> typeLiteral;
  
      public ProvisionCacheIdentityProviderFacade( final FactoryAnnotationProvider<T, A> factoryAnnotationProvider,
                                                   final TypeLiteral<T> typeLiteral )
      {
  
          this.factoryAnnotationProvider = factoryAnnotationProvider;
          this.typeLiteral = typeLiteral;
      }
  
      public Class<T> getInjectionType()
      {
          return factoryAnnotationProvider.getInjectionType();
      }
  
      public T buildValue( A annotation )
      {
          final Key<T> key = buildCacheKey( typeLiteral, annotation );
  
          if ( provisionCache.containsKey( key ) )
          {
              return provisionCache.get( key );
          }
  
          final T value = factoryAnnotationProvider.buildValue( annotation );
          provisionCache.put( key, value );
  
          return value;
      }
  
      private Key<T> buildCacheKey( final TypeLiteral<T> typeLiteral, final A annotation )
      {
  
          return Key.get( typeLiteral, annotation );
      }
  
  }