Table of Contents
OpenJPA also includes the
OpenJPAPersistence
helper class to provide
additional utility methods.
Within a container, you will typically use injection to
access an EntityManagerFactory
. Applications operating
outside of a container, however, can use the
Persistence
class to obtain
EntityManagerFactory
objects in a vendor-neutral fashion.
public static EntityManagerFactory createEntityManagerFactory(String name); public static EntityManagerFactory createEntityManagerFactory(String name, Map props); public static PersistenceUtil getPersistenceUtil();
Each createEntityManagerFactory
method searches the
system for an EntityManagerFactory
definition with the
given name. Use null
for an unnamed factory. The optional map
contains vendor-specific property settings used to further configure the
factory.
persistence.xml
files define
EntityManagerFactories
. The createEntityManagerFactory
methods search for persistence.xml
files
within the META-INF
directory of any CLASSPATH
element. For example, if your CLASSPATH
contains
the conf
directory, you could place an
EntityManagerFactory
definition in
conf/META-INF/persistence.xml
.
The getPersistenceUtil
method returns a PersistenceUtil
interface that can be used to determine whether an entity or attribute of an
entity is loaded.
PersistenceUtil pUtil = Persistence.getPersistenceUtil(); if (!pUtil.isLoaded(myEntity)) { loadEntity(myEntity); }
With the introduction of JPA 2.0, there are two versions of the
persistence.xml
. The most current revision of the
2.0 persistence schema is presented below. Version 1.0 of the persistence
schema can be found at
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd.
<?xml version="1.0" encoding="UTF-8"?> <!-- persistence.xml schema --> <xsd:schema targetNamespace="http://java.sun.com/xml/ns/persistence" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:persistence="http://java.sun.com/xml/ns/persistence" elementFormDefault="qualified" attributeFormDefault="unqualified" version="2.0"> <xsd:annotation> <xsd:documentation> @(#)persistence_2_0.xsd 1.0 October 1 2009 </xsd:documentation> </xsd:annotation> <xsd:annotation> <xsd:documentation> DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. Copyright 2005-2009 Sun Microsystems, Inc. All rights reserved. The contents of this file are subject to the terms of either the GNU General Public License Version 2 only ("GPL") or the Common Development and Distribution License("CDDL") (collectively, the "License"). You may not use this file except in compliance with the License. You can obtain a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific language governing permissions and limitations under the License. When distributing the software, include this License Header Notice in each file and include the License file at glassfish/bootstrap/legal/LICENSE.txt. Sun designates this particular file as subject to the "Classpath" exception as provided by Sun in the GPL Version 2 section of the License file that accompanied this code. If applicable, add the following below the License Header, with the fields enclosed by brackets [] replaced by your own identifying information: "Portions Copyrighted [year] [name of copyright owner]" Contributor(s): If you wish your version of this file to be governed by only the CDDL or only the GPL Version 2, indicate your decision by adding "[Contributor] elects to include this software in this distribution under the [CDDL or GPL Version 2] license." If you don't indicate a single choice of license, a recipient has the option to distribute your version of this file under either the CDDL, the GPL Version 2 or to extend the choice of license to its licensees as provided above. However, if you add GPL Version 2 code and therefore, elected the GPL Version 2 license, then the option applies only if the new code is made subject to such option by the copyright holder. </xsd:documentation> </xsd:annotation> <xsd:annotation> <xsd:documentation> <![CDATA[ This is the XML Schema for the persistence configuration file. The file must be named "META-INF/persistence.xml" in the persistence archive. Persistence configuration files must indicate the persistence schema by using the persistence namespace: http://java.sun.com/xml/ns/persistence and indicate the version of the schema by using the version element as shown below: <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" version="2.0"> ... </persistence> ]]> </xsd:documentation> </xsd:annotation> <xsd:simpleType name="versionType"> <xsd:restriction base="xsd:token"> <xsd:pattern value="[0-9]+(\.[0-9]+)*" /> </xsd:restriction> </xsd:simpleType> <!-- **************************************************** --> <xsd:element name="persistence"> <xsd:complexType> <xsd:sequence> <!-- **************************************************** --> <xsd:element name="persistence-unit" minOccurs="1" maxOccurs="unbounded"> <xsd:complexType> <xsd:annotation> <xsd:documentation> Configuration of a persistence unit. </xsd:documentation> </xsd:annotation> <xsd:sequence> <!-- **************************************************** --> <xsd:element name="description" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> Description of this persistence unit. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="provider" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> Provider class that supplies EntityManagers for this persistence unit. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="jta-data-source" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> The container-specific name of the JTA datasource to use. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="non-jta-data-source" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> The container-specific name of a non-JTA datasource to use. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="mapping-file" type="xsd:string" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> File containing mapping information. Loaded as a resource by the persistence provider. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="jar-file" type="xsd:string" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> Jar file that is to be scanned for managed classes. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="class" type="xsd:string" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> Managed class to be included in the persistence unit and to scan for annotations. It should be annotated with either @Entity, @Embeddable or @MappedSuperclass. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="exclude-unlisted-classes" type="xsd:boolean" default="true" minOccurs="0"> <xsd:annotation> <xsd:documentation> When set to true then only listed classes and jars will be scanned for persistent classes, otherwise the enclosing jar or directory will also be scanned. Not applicable to Java SE persistence units. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="shared-cache-mode" type="persistence:persistence-unit-caching-type" minOccurs="0"> <xsd:annotation> <xsd:documentation> Defines whether caching is enabled for the persistence unit if caching is supported by the persistence provider. When set to ALL, all entities will be cached. When set to NONE, no entities will be cached. When set to ENABLE_SELECTIVE, only entities specified as cacheable will be cached. When set to DISABLE_SELECTIVE, entities specified as not cacheable will not be cached. When not specified or when set to UNSPECIFIED, provider defaults may apply. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="validation-mode" type="persistence:persistence-unit-validation-mode-type" minOccurs="0"> <xsd:annotation> <xsd:documentation> The validation mode to be used for the persistence unit. </xsd:documentation> </xsd:annotation> </xsd:element> <!-- **************************************************** --> <xsd:element name="properties" minOccurs="0"> <xsd:annotation> <xsd:documentation> A list of standard and vendor-specific properties and hints. </xsd:documentation> </xsd:annotation> <xsd:complexType> <xsd:sequence> <xsd:element name="property" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> A name-value pair. </xsd:documentation> </xsd:annotation> <xsd:complexType> <xsd:attribute name="name" type="xsd:string" use="required" /> <xsd:attribute name="value" type="xsd:string" use="required" /> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:element> </xsd:sequence> <!-- **************************************************** --> <xsd:attribute name="name" type="xsd:string" use="required"> <xsd:annotation> <xsd:documentation> Name used in code to reference this persistence unit. </xsd:documentation> </xsd:annotation> </xsd:attribute> <!-- **************************************************** --> <xsd:attribute name="transaction-type" type="persistence:persistence-unit-transaction-type"> <xsd:annotation> <xsd:documentation> Type of transactions used by EntityManagers from this persistence unit. </xsd:documentation> </xsd:annotation> </xsd:attribute> </xsd:complexType> </xsd:element> </xsd:sequence> <xsd:attribute name="version" type="persistence:versionType" fixed="2.0" use="required" /> </xsd:complexType> </xsd:element> <!-- **************************************************** --> <xsd:simpleType name="persistence-unit-transaction-type"> <xsd:annotation> <xsd:documentation> public enum PersistenceUnitTransactionType {JTA, RESOURCE_LOCAL}; </xsd:documentation> </xsd:annotation> <xsd:restriction base="xsd:token"> <xsd:enumeration value="JTA" /> <xsd:enumeration value="RESOURCE_LOCAL" /> </xsd:restriction> </xsd:simpleType> <!-- **************************************************** --> <xsd:simpleType name="persistence-unit-caching-type"> <xsd:annotation> <xsd:documentation> public enum SharedCacheMode { ALL, NONE, ENABLE_SELECTIVE, DISABLE_SELECTIVE, UNSPECIFIED}; </xsd:documentation> </xsd:annotation> <xsd:restriction base="xsd:token"> <xsd:enumeration value="ALL" /> <xsd:enumeration value="NONE" /> <xsd:enumeration value="ENABLE_SELECTIVE" /> <xsd:enumeration value="DISABLE_SELECTIVE" /> <xsd:enumeration value="UNSPECIFIED" /> </xsd:restriction> </xsd:simpleType> <!-- **************************************************** --> <xsd:simpleType name="persistence-unit-validation-mode-type"> <xsd:annotation> <xsd:documentation> public enum ValidationMode { AUTO, CALLBACK, NONE}; </xsd:documentation> </xsd:annotation> <xsd:restriction base="xsd:token"> <xsd:enumeration value="AUTO" /> <xsd:enumeration value="CALLBACK" /> <xsd:enumeration value="NONE" /> </xsd:restriction> </xsd:simpleType> </xsd:schema>
The root element of a persistence.xml
file is
persistence
, which then contains one or more
persistence-unit
definitions. The root element should include the
version attribute with the appropriate version, 1.0
for a
version 1.0 file and 2.0
for a version 2.0 file. Each
persistence unit describes the configuration for the entity managers created by
the persistence unit's entity manager factory. The persistence unit can specify
these elements and attributes.
name
: This is the name you pass to the
Persistence.createEntityManagerFactory
methods described above. The
name attribute is required.
transaction-type
: Whether to use managed
(JTA
) or local (RESOURCE_LOCAL
)
transaction management.
provider
: If you are using a third-party JPA vendor, this
element names its implementation of the
PersistenceProvider
bootstrapping interface.
Set the provider
to
org.apache.openjpa.persistence.PersistenceProviderImpl
to use
OpenJPA.
jta-data-source
: The JNDI name of a JDBC
DataSource
that is automatically enlisted in JTA transactions. This
may be an XA DataSource
.
non-jta-data-source
: The JNDI name of a JDBC
DataSource
that is not enlisted in JTA transactions.
mapping-file
*: The resource names of XML mapping files for
entities and embeddable classes. You can also specify mapping information in an
orm.xml
file in your META-INF
directory. If present, the orm.xml
mapping file will be
read automatically.
jar-file
*: The names of jar files containing entities and
embeddable classes. The implementation will scan the jar for annotated classes.
class
*: The class names of entities and embeddable classes.
properties
: This element contains nested property
elements used to specify vendor-specific settings. Each
property
has a name attribute and a value attribute.
The Reference Guide's Chapter 2, Configuration describes OpenJPA's configuration properties.
Here is a typical persistence.xml
file for a non-EE
environment:
Example 6.1. persistence.xml
<?xml version="1.0"?> <persistence version="1.0"> <persistence-unit name="openjpa"> <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider> <class>tutorial.Animal</class> <class>tutorial.Dog</class> <class>tutorial.Rabbit</class> <class>tutorial.Snake</class> <properties> <property name="openjpa.ConnectionURL" value="jdbc:hsqldb:tutorial_database"/> <property name="openjpa.ConnectionDriverName" value="org.hsqldb.jdbcDriver"/> <property name="openjpa.ConnectionUserName" value="sa"/> <property name="openjpa.ConnectionPassword" value=""/> <property name="openjpa.Log" value="DefaultLevel=WARN, Tool=INFO"/> </properties> </persistence-unit> </persistence>