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.

The simplest way of creating a PersistenceManagerFactory is as follows

Properties properties = new Properties();
properties.setProperty("javax.jdo.PersistenceManagerFactoryClass",
                "{my_implementation_pmf_class}");
properties.setProperty("javax.jdo.option.ConnectionDriverName","com.mysql.jdbc.Driver");
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 ("jdo.properties" for example) to specify these properties like this

javax.jdo.PersistenceManagerFactoryClass={my_implementation_pmf_class}
javax.jdo.option.ConnectionDriverName=com.mysql.jdbc.Driver
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");

A final alternative 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.