src/main/asciidoc/jdohelper.adoc

:_basedir: 
:_imagesdir: images/
:grid: cols
:usage:

[[index]]

== 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:api32/apidocs/javax/jdo/JDOHelper.html[image:images/javadoc.png[image]]


[[pmf]]
=== 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} +


[[pm]]
=== 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]]
=== Lifecycle methods

Now we move onto lifecycle operations

* *getObjectState(Object pc)* - returns the object state
* *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