1 package org.apache.onami.persist;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import javax.inject.Inject;
23 import javax.inject.Singleton;
24 import javax.persistence.EntityManager;
25 import javax.persistence.EntityManagerFactory;
26 import java.util.Properties;
27
28 import static org.apache.onami.persist.Preconditions.checkNotNull;
29
30 /**
31 * Implementation of {@link EntityManagerProvider} and {@link UnitOfWork}.
32 */
33 @Singleton
34 class EntityManagerProviderImpl
35 implements EntityManagerProvider, UnitOfWork
36 {
37
38 /**
39 * Provider for {@link javax.persistence.EntityManagerFactory}.
40 */
41 private final EntityManagerFactoryProvider emfProvider;
42
43 /**
44 * Additional properties to be set on every {@link EntityManager} which is created.
45 */
46 private final Properties properties;
47
48 /**
49 * Thread local store of {@link EntityManager}s.
50 */
51 private final ThreadLocal<EntityManager> entityManagers = new ThreadLocal<EntityManager>();
52
53 /**
54 * Constructor.
55 *
56 * @param emfProvider the provider for {@link EntityManagerFactory}. Must not be {@code null}.
57 * @param properties additional properties to be set on every {@link EntityManager} which is created.
58 */
59 @Inject
60 public EntityManagerProviderImpl( EntityManagerFactoryProvider emfProvider,
61 @Nullable @ForContainerManaged Properties properties )
62 {
63 this.emfProvider = checkNotNull( emfProvider, "emfProvider is mandatory!" );
64 this.properties = properties;
65 }
66
67 /**
68 * {@inheritDoc}
69 */
70 // @Override
71 public EntityManager get()
72 throws IllegalStateException
73 {
74 final EntityManager entityManager = entityManagers.get();
75 if ( entityManager != null )
76 {
77 return entityManager;
78 }
79 else
80 {
81 throw new IllegalStateException( "UnitOfWork is not running." );
82 }
83 }
84
85 /**
86 * {@inheritDoc}
87 */
88 // @Override
89 public void begin()
90 {
91 if ( isActive() )
92 {
93 throw new IllegalStateException( "Unit of work has already been started." );
94 }
95 else
96 {
97 final EntityManager em = createEntityManager();
98 entityManagers.set( em );
99 }
100 }
101
102 /**
103 * @return a new entity manager instance.
104 */
105 private EntityManager createEntityManager()
106 {
107 final EntityManagerFactory emf = emfProvider.get();
108 if ( null == properties )
109 {
110 return emf.createEntityManager();
111 }
112 else
113 {
114 return emf.createEntityManager( properties );
115 }
116 }
117
118 /**
119 * {@inheritDoc}
120 */
121 // @Override
122 public boolean isActive()
123 {
124 return entityManagers.get() != null;
125 }
126
127 /**
128 * {@inheritDoc}
129 */
130 // @Override
131 public void end()
132 {
133 final EntityManager em = entityManagers.get();
134 if ( em != null )
135 {
136 closeAndRemoveEntityManager( em );
137 }
138 }
139
140 /**
141 * closes the entity manager and removes it from the internal storage.
142 *
143 * @param em the entity manager to close
144 */
145 private void closeAndRemoveEntityManager( EntityManager em )
146 {
147 try
148 {
149 em.close();
150 }
151 finally
152 {
153 entityManagers.remove();
154 }
155 }
156
157 }