001// Copyright 2011 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5.internal.jpa; 016 017import javax.persistence.EntityManager; 018import javax.persistence.PersistenceContext; 019 020import org.apache.tapestry5.ioc.AnnotationProvider; 021import org.apache.tapestry5.ioc.ObjectCreator; 022import org.apache.tapestry5.ioc.ObjectLocator; 023import org.apache.tapestry5.ioc.ObjectProvider; 024import org.apache.tapestry5.ioc.services.ClassFactory; 025import org.apache.tapestry5.jpa.EntityManagerManager; 026 027public class EntityManagerObjectProvider implements ObjectProvider 028{ 029 030 private EntityManager proxy; 031 032 /** 033 * {@inheritDoc} 034 */ 035 public <T> T provide(final Class<T> objectType, final AnnotationProvider annotationProvider, 036 final ObjectLocator locator) 037 { 038 if (objectType.equals(EntityManager.class)) 039 return objectType.cast(getOrCreateProxy(annotationProvider, locator)); 040 041 return null; 042 } 043 044 private synchronized EntityManager getOrCreateProxy( 045 final AnnotationProvider annotationProvider, final ObjectLocator objectLocator) 046 { 047 if (proxy == null) 048 { 049 final ClassFactory classFactory = objectLocator.getService("ClassFactory", 050 ClassFactory.class); 051 052 final PersistenceContext annotation = annotationProvider 053 .getAnnotation(PersistenceContext.class); 054 055 proxy = classFactory.createProxy(EntityManager.class, new ObjectCreator() 056 { 057 public Object createObject() 058 { 059 final EntityManagerManager entityManagerManager = objectLocator 060 .getService(EntityManagerManager.class); 061 062 return JpaInternalUtils.getEntityManager(entityManagerManager, annotation); 063 } 064 }, "<EntityManagerProxy>"); 065 } 066 067 return proxy; 068 } 069 070}