1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19
20 //
21 // This source code implements specifications defined by the Java
22 // Community Process. In order to remain compliant with the specification
23 // DO NOT add / change / or delete method signatures!
24 //
25 package javax.persistence;
26
27 import java.io.BufferedReader;
28 import java.io.IOException;
29 import java.io.InputStreamReader;
30 import java.net.URL;
31 import java.util.Collections;
32 import java.util.Enumeration;
33 import java.util.Map;
34 import java.util.HashSet;
35 import java.util.Set;
36
37 import javax.persistence.spi.PersistenceProvider;
38
39 /**
40 * @version $Rev: 529834 $ $Date: 2007-04-17 19:32:23 -0700 (Tue, 17 Apr 2007) $
41 */
42
43 /**
44 * Bootstrap class that is used to obtain {@link javax.persistence.EntityManagerFactory}
45 * references.
46 */
47 public class Persistence {
48
49 protected static final Set<PersistenceProvider> providers = new HashSet<PersistenceProvider>();
50 // Changed to the hard coded PERSISTENCE_PROVIDER value to pass signature tests.
51 // public static final java.lang.String PERSISTENCE_PROVIDER = PersistenceProvider.class.getName();
52 public static final java.lang.String PERSISTENCE_PROVIDER = "javax.persistence.spi.PeristenceProvider";
53 static final String PERSISTENCE_PROVIDER_PROPERTY = "javax.persistence.provider";
54 static final String PERSISTENCE_PROVIDER_SERVICE = "META-INF/services/"
55 + PersistenceProvider.class.getName();
56
57 /**
58 * Create and return an EntityManagerFactory for the named persistence unit.
59 *
60 * @param persistenceUnitName The name of the persistence unit
61 * @return The factory that creates EntityManagers configured according to the
62 * specified persistence unit
63 */
64 public static EntityManagerFactory createEntityManagerFactory(
65 String persistenceUnitName) {
66 return createEntityManagerFactory(persistenceUnitName, Collections.EMPTY_MAP);
67 }
68
69 /**
70 * Create and return an EntityManagerFactory for the named persistence unit using the
71 * given properties.
72 *
73 * @param persistenceUnitName The name of the persistence unit
74 * @param properties Additional properties to use when creating the factory. The values of
75 * these properties override any values that may have been configured
76 * elsewhere.
77 * @return The factory that creates EntityManagers configured according to the
78 * specified persistence unit.
79 */
80 public static EntityManagerFactory createEntityManagerFactory(
81 String persistenceUnitName,
82 Map properties) {
83
84 if (properties == null) {
85 properties = Collections.EMPTY_MAP;
86 }
87
88 // start by loading a provider explicitly specified in properties. The spec
89 // doesn't seem to forbid providers that are not deployed as a service
90 Object providerName = properties.get(PERSISTENCE_PROVIDER_PROPERTY);
91 if (providerName instanceof String) {
92 EntityManagerFactory factory = createFactory(
93 providerName.toString(),
94 persistenceUnitName,
95 properties);
96 if (factory != null) {
97 return factory;
98 }
99 }
100
101 // load correctly deployed providers
102 ClassLoader loader = Thread.currentThread().getContextClassLoader();
103 try {
104 Enumeration<URL> providers = loader
105 .getResources(PERSISTENCE_PROVIDER_SERVICE);
106 while (providers.hasMoreElements()) {
107
108 String name = getProviderName(providers.nextElement());
109
110 if (name != null) {
111
112 EntityManagerFactory factory = createFactory(
113 name,
114 persistenceUnitName,
115 properties);
116
117 if (factory != null) {
118 return factory;
119 }
120 }
121 }
122 }
123 catch (IOException e) {
124 // spec doesn't mention any exceptions thrown by this method
125 }
126
127 return null;
128 }
129
130 static String getProviderName(URL url) throws IOException {
131
132 BufferedReader in = new BufferedReader(new InputStreamReader(
133 url.openStream(),
134 "UTF-8"));
135
136 String providerName;
137
138 try {
139 providerName = in.readLine();
140 }
141 finally {
142 in.close();
143 }
144
145 if (providerName != null) {
146 providerName = providerName.trim();
147 }
148
149 return providerName;
150 }
151
152 static EntityManagerFactory createFactory(
153 String providerName,
154 String persistenceUnitName,
155 Map properties)
156 throws PersistenceException {
157
158 Class providerClass;
159 try {
160 providerClass = Class.forName(providerName, true, Thread
161 .currentThread().getContextClassLoader());
162 }
163 catch (Exception e) {
164 throw new PersistenceException(
165 "Invalid or inaccessible provider class: " + providerName,
166 e);
167 }
168
169 try {
170 PersistenceProvider provider = (PersistenceProvider) providerClass
171 .newInstance();
172 return provider.createEntityManagerFactory(persistenceUnitName,
173 properties);
174 }
175 catch (Exception e) {
176 throw new PersistenceException("Provider error. Provider: "
177 + providerName, e);
178 }
179 }
180 }