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 org.apache.tapestry5.ioc.AnnotationProvider; 018import org.apache.tapestry5.ioc.ObjectCreator; 019import org.apache.tapestry5.ioc.ObjectLocator; 020import org.apache.tapestry5.ioc.ObjectProvider; 021import org.apache.tapestry5.ioc.services.PlasticProxyFactory; 022import org.apache.tapestry5.jpa.EntityManagerManager; 023 024import javax.persistence.EntityManager; 025import javax.persistence.PersistenceContext; 026 027public class EntityManagerObjectProvider implements ObjectProvider 028{ 029 030 private EntityManager proxy; 031 032 public <T> T provide(final Class<T> objectType, final AnnotationProvider annotationProvider, 033 final ObjectLocator locator) 034 { 035 if (objectType.equals(EntityManager.class)) 036 return objectType.cast(getOrCreateProxy(annotationProvider, locator)); 037 038 return null; 039 } 040 041 private synchronized EntityManager getOrCreateProxy( 042 final AnnotationProvider annotationProvider, final ObjectLocator objectLocator) 043 { 044 if (proxy == null) 045 { 046 final PlasticProxyFactory proxyFactory = objectLocator.getService("PlasticProxyFactory", 047 PlasticProxyFactory.class); 048 049 final PersistenceContext annotation = annotationProvider 050 .getAnnotation(PersistenceContext.class); 051 052 proxy = proxyFactory.createProxy(EntityManager.class, new ObjectCreator() 053 { 054 public Object createObject() 055 { 056 final EntityManagerManager entityManagerManager = objectLocator 057 .getService(EntityManagerManager.class); 058 059 return JpaInternalUtils.getEntityManager(entityManagerManager, annotation); 060 } 061 }, "<EntityManagerProxy>"); 062 } 063 064 return proxy; 065 } 066 067}