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== JDOHelperanchor:JDOHelper[]

JDO provides a standard utility that gives access to useful parts of the
JDO persistence process. This is known as *JDOHelper*
(javax.jdo.JDOHelper)
link:api20/apidocs/javax/jdo/JDOHelper.html[image:images/javadoc.png[image]]

=== PersistenceManagerFactory methodsanchor:PersistenceManagerFactory_methods[]

The methods in JDOHelper can be split into categories. Here we start
with the methods for creating the starting point for persistence, the
PersistenceManagerFactory (PMF)

* *getPersistenceManagerFactory(Map props)* - creates a PMF given a Map
of the properties
* *getPersistenceManagerFactory(Map props, ClassLoader cl)* - creates a
PMF given a Map of the properties, and a ClassLoader to use
* *getPersistenceManagerFactory(String resource)* - creates a PMF given
a resource defining the properties. This can be used to create a named
PMF in JDO2.1
* *getPersistenceManagerFactory(String props, ClassLoader cl)* - creates
a PMF given a resource defining the properties, and a ClassLoader to use
* *getPersistenceManagerFactory(File props)* - creates a PMF given a
file containing the properties
* *getPersistenceManagerFactory(File props, ClassLoader cl)* - creates a
PMF given a file containing the properties and a ClassLoader to use
* *getPersistenceManagerFactory(String jndi, Context ctx)* - creates a
PMF given a JNDI resource
* *getPersistenceManagerFactory(String jndi, Context ctx, ClassLoader
cl)* - creates a PMF given a JNDI resource and a ClassLoader to use
* *getPersistenceManagerFactory(InputStream strm)* - creates a PMF given
an InputStream
* *getPersistenceManagerFactory(InputStream strm, ClassLoader cl)* -
creates a PMF given an InputStream and a ClassLoader to use

{empty} +


=== Persistence methodsanchor:Persistence_methods[]

Now we move onto the operations for persistence.

* *getPersistenceManager(Object pc)* - returns the PersistenceManager
associated with the passed object (if any)
* *makeDirty(Object pc, String fieldName)* - marks the field of the
passed object as dirty (meaning that it needs updating in its
datastore)
* *getObjectId(Object pc)* - returns the object identity for the passed
object (if persistent)
* *getObjectIds(Collection pc)* - returns the object identities for the
passed objects (if persistent)
* *getObjectIds(Object[] pc)* - returns the object identities for the
passed objects (if persistent)
* *getVersion(Object pc)* - returns the version for the passed object
(if persistent)

{empty} +


=== Lifecycle methodsanchor:Lifecycle_methods[]

Now we move onto lifecycle operations

* *getObjectState(Object pc)* - returns the object state (JDO2.1 JDK1.5+
only)
* *isDirty(Object pc)* - returns whether the passed object is dirty
* *isTransactional(Object pc)* - returns whether the passed object is
transactional
* *isPersistent(Object pc)* - returns whether the passed object is
persistent
* *isNew(Object pc)* - returns whether the passed object is new
* *isDeleted(Object pc)* - returns whether the passed object is deleted
* *isDetached(Object pc)* - returns whether the passed object is
detached