Persistence Manager Factory

Any JDO-enabled application will require (at least) one PersistenceManagerFactory. Typically applications create one per datastore being utilised. A PersistenceManagerFactory provides access to PersistenceManagers which allow objects to be persisted, and retrieved. The PersistenceManagerFactory can be configured to provide particular behaviour.

A simple way of creating a PersistenceManagerFactory is using a set of properties controlling its behaviour, as follows

Properties properties = new Properties();
properties.setProperty("javax.jdo.PersistenceManagerFactoryClass", "{my_implementation_pmf_class}");
properties.setProperty("javax.jdo.option.ConnectionURL", "jdbc:mysql://localhost/myDB");
properties.setProperty("javax.jdo.option.ConnectionUserName", "login");
properties.setProperty("javax.jdo.option.ConnectionPassword", "password");
PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory(properties);

A slight variation on this, is to use a file containg these properties (jdo.properties for example) to create the PMF, like this

javax.jdo.PersistenceManagerFactoryClass={my_implementation_pmf_class}
javax.jdo.option.ConnectionURL=jdbc:mysql://localhost/myDB
javax.jdo.option.ConnectionUserName=login
javax.jdo.option.ConnectionPassword=password

and then to create the PersistenceManagerFactory using this file

PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory("jdo.properties");

You could alternatively make use of a JPA persistence.xml file to create a PMF, like this

<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns="https://jakarta.ee/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence
        https://jakarta.ee/xml/ns/persistence/persistence_3_0.xsd" version="3.0">
    <!-- MyApp persistence unit -->
    <persistence-unit name="MyApp">
        <class>mydomain.Product</class>
        <class>mydomain.Book</class>
        <class>mydomain.CompactDisc</class>
        <exclude-unlisted-classes/>
        <properties>
            <property name="datanucleus.ConnectionURL" value="jdbc:mysql://localhost/myDB"/>
            <property name="datanucleus.ConnectionUserName" value="mysql"/>
            <property name="datanucleus.ConnectionPassword" value=""/>
        </properties>
    </persistence-unit>
</persistence>

and then instantiate the PMF using the persistence unit name, defining the classes that have JDO annotations that make up this application.

PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory("MyApp");

An alternative using JNDI would be to call JDOHelper.getPersistenceManagerFactory(jndiLocation, context);, hence accessing the properties via JNDI.

Whichever way we wish to obtain the PersistenceManagerFactory we have defined a series of properties to give the behaviour of the PersistenceManagerFactory. The first property specifies to use PMF of the implementation required to be used, and the following 4 properties define the datastore that it should connect to.

Standard JDO Properties

Name

Description

javax.jdo.PersistenceManagerFactoryClass

The name of the PersistenceManager implementation

javax.jdo.option.ConnectionFactory

Instance of a connection factory. For RBDMS, it must be an instance of javax.sql.DataSource. This is for a transactional DataSource

javax.jdo.option.ConnectionFactory2

Instance of a connection factory. For RBDMS, it must be an instance of javax.sql.DataSource. This is for a non-transactional DataSource

javax.jdo.option.ConnectionFactoryName

The JNDI name for a connection factory. For RBDMS, it must be a JNDI name that points to a javax.sql.DataSource object. This is for a transactional DataSource

javax.jdo.option.ConnectionFactory2Name

The JNDI name for a connection factory. For RBDMS, it must be a JNDI name that points to a javax.sql.DataSource object. This is for a non-transactional DataSource

javax.jdo.option.ConnectionDriverName

The name of the driver to use for the DB

javax.jdo.option.ConnectionDriverURL

URL specifying the datastore to use for persistence

javax.jdo.option.ConnectionUserName

Username to use for connecting to the DB

javax.jdo.option.ConnectionPassword

Password to use for connecting to the DB

javax.jdo.option.IgnoreCache

Whether to ignore the cache for queries. Range of Values: true | false

javax.jdo.option.Multithreaded

Whether to run the PersistenceManager multithreaded. Range of Values: true | false

javax.jdo.option.NontransactionalRead

Whether to allow nontransactional reads. Range of Values: true | false

javax.jdo.option.NontransactionalWrite

Whether to allow nontransactional writes. Range of Values: true | false

javax.jdo.option.Optimistic

Whether to use Optimistic locking on transactions. Range of Values: true | false

javax.jdo.option.RetainValues

Whether to suppress the clearing of values from persistent instances on transaction completion. Range of Values: true | false

javax.jdo.option.RestoreValues

Whether persistent object have transactional field values restored when transaction rollback occurs. Range of Values: true | false

javax.jdo.option.Mapping

Name for the ORM MetaData mapping files to use with this PMF. For example if this is set to "mysql" then the implementation looks for MetaData mapping files called "{classname}-mysql.orm" or "package-mysql.orm". If this is not specified then the JDO implementation assumes that all is specified in the JDO MetaData file. ORM datastores only

javax.jdo.mapping.Catalog

Name of the catalog to use by default for all classes persisted using this PMF. This can be overridden in the MetaData where required, and is optional. ORM datastores only

javax.jdo.mapping.Schema

Name of the schema to use by default for all classes persisted using this PMF. This can be overridden in the MetaData where required, and is optional. ORM datastores only

javax.jdo.option.DetachAllOnCommit

Allows the user to select that when a transaction is committed all objects enlisted in that transaction will be automatically detached. Range of Values: true | false

javax.jdo.option.CopyOnAttach

Whether, when attaching a detached object, we create an attached copy or simply migrate the detached object to attached state. Range of Values: true | false

javax.jdo.option.TransactionType

Type of transaction to use. If running under JavaSE the default is RESOURCE_LOCAL, and if running under JavaEE/JakartaEE the default is JTA. Range of Values: RESOURCE_LOCAL | JTA

javax.jdo.option.PersistenceUnitName

Name of the "persistence-unit" to use with this PMF. This borrows the "persistence-unit" concept from JPA for use with JDO.

javax.jdo.option.ServerTimeZoneID

Id of the TimeZone under which the datastore server is running. If this is not specified or is set to null it is assumed that the datastore server is running in the same timezone as the JVM under which the implementation is running.

javax.jdo.option.Name

Name of the PMF. This is for use with "named PMF" functionality (see jdoconfig.xml).

javax.jdo.option.ReadOnly

Whether this datastore should be treated as read only. Range of Values: true | false

javax.jdo.option.TransactionIsolationLevel