/*

  * 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.lang.reflect.Field;

 import org.apache.onami.factoryannotation.AccessibleHelper.AccessibleHelperCallback;

 import com.google.inject.MembersInjector;

 import com.google.inject.ProvisionException;

 class FactoryAnnotationSingleFieldMemberInjector<T, A extends Annotation>

     implements MembersInjector<T>

 {

     private final FactoryAnnotationProvider<T, A> factoryAnnotationProvider;

     private final Field field;

     private final A annotation;

     private final FactoryAnnotationProvision<T, A> factoryAnnotationProvision;

     private final FactoryAnnotationProvisionListener<T, A> provisionListener;

     FactoryAnnotationSingleFieldMemberInjector( final FactoryAnnotationProvider<T, A> factoryAnnotationProvider, final Field field,

                                        final FactoryAnnotationProvisionListener<T, A> provisionListener, final A annotation,

                                        final FactoryAnnotationProvision<T, A> factoryAnnotationProvision )

     {

         this.factoryAnnotationProvider = factoryAnnotationProvider;

         this.field = field;

         this.annotation = annotation;

         this.factoryAnnotationProvision = factoryAnnotationProvision;

         this.provisionListener = provisionListener;

     }

     public void injectMembers( final T instance )

     {

         AccessibleHelper.executePrivileged( field, new AccessibleHelperCallback<Field>()

         {

             public void execute( final Field accessibleObject )

             {

                 try

                 {

                     // If annotated with both @Inject and a binding

                     // annotation it is possible that there would be two

                     // injection request, so just prevent injecting a

                     // value a second time

                     if ( accessibleObject.get( instance ) == null )

                     {

                         final FactoryAnnotationProvision<T, A> ip = FactoryAnnotationProvisionImpl.modify( factoryAnnotationProvision, instance );

                         final T value = factoryAnnotationProvider.buildValue( annotation );

                         // Notify listener before we inject the value

                         if ( provisionListener != null )

                         {

                             provisionListener.beforeInjection( ip, annotation );

                         }

                         accessibleObject.set( instance, value );

                         // Notify listener after injection is done

                         if ( provisionListener != null )

                         {

                             provisionListener.afterInjection( ip, annotation, value );

                         }

                     }

                 }

                 catch ( final IllegalAccessException e )

                 {

                     throw new ProvisionException( "Provision failed", e );

                 }

             }

         } );

     }

     @SuppressWarnings( "unchecked" )

     static final <A extends Annotation, I, T> MembersInjector<I> buildMemberInjector( final FactoryAnnotationProvider<T, A> factoryAnnotationProvider,

                                                                                       final Field field,

                                                                                       final FactoryAnnotationProvisionListener<T, A> provisionListener,

                                                                                       final A annotation,

                                                                                       final FactoryAnnotationProvision<T, A> factoryAnnotationProvision )

     {

         return (MembersInjector<I>) new FactoryAnnotationSingleFieldMemberInjector<T, A>( factoryAnnotationProvider, field,

                                                                                  provisionListener, annotation,

                                                                                  factoryAnnotationProvision );

     }

 }