content: /*****************************************************************
   *   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
   *
   *    https://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.cayenne.di.spi;
  
  import org.apache.cayenne.di.DIRuntimeException;
  import org.apache.cayenne.di.Provider;
  
  import java.lang.reflect.Field;
  
  /**
   * @since 4.0
   */
  class FieldInjectingDecoratorProvider<T> implements DecoratorProvider<T> {
  
      private Class<? extends T> implementation;
      private DefaultInjector injector;
      private DecoratorProvider<T> delegate;
  
      FieldInjectingDecoratorProvider(Class<? extends T> implementation, DecoratorProvider<T> delegate,
              DefaultInjector injector) {
          this.delegate = delegate;
          this.injector = injector;
          this.implementation = implementation;
      }
  
      @Override
      public Provider<T> get(final Provider<T> undecorated) throws DIRuntimeException {
          return new FieldInjectingProvider<T>(delegate.get(undecorated), injector) {
  
              @Override
              protected Object value(Field field, String bindingName) {
                  Class<?> fieldType = field.getType();
  
                  // delegate (possibly) injected as Provider
                  if (Provider.class.equals(fieldType)) {
  
                      Class<?> objectClass = DIUtil.parameterClass(field.getGenericType());
  
                      if (objectClass == null) {
                          throw new DIRuntimeException("Provider field %s.%s of type %s must be "
                                  + "parameterized to be usable for injection", field.getDeclaringClass().getName(),
                                  field.getName(), fieldType.getName());
                      }
  
                      if(objectClass.isAssignableFrom(implementation)) {
                          return undecorated;
                      }
                  }
                  else if (fieldType.isAssignableFrom(implementation)) {
                      return undecorated.get();
                  }
  
                  return super.value(field, bindingName);
              }
          };
      }
  }
  