2 * Copyright 2005-2010 the original author or authors.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package org.wamblee.test.transactions;
18 import java.lang.reflect.InvocationHandler;
19 import java.lang.reflect.InvocationTargetException;
20 import java.lang.reflect.Method;
21 import java.lang.reflect.Proxy;
22 import java.util.logging.Level;
24 import javax.persistence.EntityManager;
26 import org.wamblee.general.ThreadSpecificProxyFactory;
27 import org.wamblee.test.persistence.JpaBuilder;
28 import org.wamblee.test.persistence.LoggingTransactionResultCallback;
29 import org.wamblee.test.persistence.JpaBuilder.JpaUnitOfWork;
32 * This utility makes sure that each invocation on a certain interface is
33 * carried out within a JPA unit of work. Note that this is equivalent to the
34 * sementics of a requiresNew transaction attribute.
36 * Use {@link #getTransactionScopedEntityManager()} to get the transaction
37 * scoped entity manager to pass to services.
43 * JpaBuilder builder = ...
44 * TransactionProxyFactory<Service> factory = new TransactionProxyFactory<Service>(
45 * builder, Service.class);
46 * Service service = new JpaService(factory.getTransactionScopedEntityManager());
47 * Service proxy = factory.getProxy(service);
48 * proxy.executeMethod(...);
51 * The above example executes the executeMethod() call on the service object
52 * within an active transaction. In the constructor of the service a transaction
53 * scoped entity manager is passed.
56 * Type of interface to proxy.
58 * @author Erik Brakkee
60 public class TransactionProxyFactory<T> {
63 * Executes the call on the service within a new transaction.
65 * @author Erik Brakkee
68 * Type of the service interface.
70 private class UnitOfWorkInvocationHandler<T> implements InvocationHandler {
74 public UnitOfWorkInvocationHandler(T aService) {
79 public Object invoke(Object aProxy, final Method aMethod,
80 final Object[] aArgs) throws Throwable {
81 return TransactionProxyFactory.this.jpaBuilder.execute(
82 new JpaUnitOfWork<Object>() {
84 public Object execute(EntityManager aEm) throws Exception {
85 EntityManager oldEm = ENTITY_MANAGER.get();
87 ENTITY_MANAGER.set(aEm);
88 return aMethod.invoke(service, aArgs);
89 } catch (InvocationTargetException e) {
90 Throwable cause = e.getCause();
91 if (cause instanceof Exception) {
92 throw (Exception) cause;
93 } else if (cause instanceof Error) {
97 throw new RuntimeException(e);
99 ENTITY_MANAGER.set(oldEm);
102 }, new LoggingTransactionResultCallback(Level.INFO));
107 private static final ThreadSpecificProxyFactory<EntityManager> ENTITY_MANAGER = new ThreadSpecificProxyFactory<EntityManager>(
108 EntityManager.class);
110 private JpaBuilder jpaBuilder;
111 private Class<T> clazz;
114 * Constructs the transaction proxy.
118 public TransactionProxyFactory(JpaBuilder aJpaBuilder, Class<T> aClass) {
119 jpaBuilder = aJpaBuilder;
123 public EntityManager getTransactionScopedEntityManager() {
124 return ENTITY_MANAGER.getProxy();
127 public T getProxy(T aService) {
128 InvocationHandler handler = new UnitOfWorkInvocationHandler<T>(aService);
129 Class proxyClass = Proxy.getProxyClass(clazz.getClassLoader(),
130 new Class[] { clazz });
133 proxy = (T) proxyClass.getConstructor(
134 new Class[] { InvocationHandler.class }).newInstance(
135 new Object[] { handler });
137 } catch (Exception e) {
138 throw new RuntimeException("Could not create proxy for " +