2140 words

javax.jdo.JDOHelper - JDO class

javax.jdo
Class JDOHelper

java.lang.Object
    javax.jdo.JDOHelper
Implemented Interfaces:
Constants
This class can be used by a JDO-aware application to call the JDO behavior of PersistenceCapable instances without declaring them to be PersistenceCapable.

It is also used to acquire a PersistenceManagerFactory via various methods.

This helper class defines static methods that allow a JDO-aware application to examine the runtime state of instances. For example, an application can discover whether the instance is persistent, transactional, dirty, new, deleted, or detached; and to get its associated PersistenceManager if it has one.

Since:
JDO 1.0
Some applications might prefer to use instance methods instead of static methods.
Some applications might prefer to use instance methods instead of static methods.
Since:
JDO 2.1
Return the singleton instance of JDOHelper.
Return the singleton instance of JDOHelper. This instance is thread-safe.
Returns:
the thread-safe singleton JDOHelper
Since:
JDO 2.1
Object getObjectId(Object pc)
Return a copy of the JDO identity associated with the parameter instance.
Return a copy of the JDO identity associated with the parameter instance.

Persistent instances of PersistenceCapable classes have a JDO identity managed by the PersistenceManager. This method returns a copy of the ObjectId that represents the JDO identity.

Transient instances and instances of classes that do not implement PersistenceCapable return null.

The ObjectId may be serialized and later restored, and used with a PersistenceManager from the same JDO implementation to locate a persistent instance with the same data store identity.

If the JDO identity is managed by the application, then the ObjectId may be used with a PersistenceManager from any JDO implementation that supports the PersistenceCapable class.

If the JDO identity is not managed by the application or the data store, then the ObjectId returned is only valid within the current transaction.

Parameters:
pc - the PersistenceCapable instance.
Returns:
a copy of the ObjectId of the parameter instance as of the beginning of the transaction.
Since:
JDO 1.0
See Also:
PersistenceManager.getObjectId(Object pc)
PersistenceCapable.jdoGetObjectId()
PersistenceManager.getObjectById(Object oid, boolean validate)
Object[] getObjectIds(Object[] pcs)
Get object ids for an array of instances.
Get object ids for an array of instances. For each instance in the parameter, the getObjectId method is called. This method returns one identity instance for each element in the parameter. The order of instances of the returned array exactly matches the order of instances of the parameter array.
Parameters:
pcs - the persistence-capable instances
Returns:
the object ids of the parameters
Since:
JDO 2.0
See Also:
getObjectId(Object pc)
getObjectIds(Collection pcs)
Collection getObjectIds(Collection pcs)
Get object ids for a collection of instances.
Get object ids for a collection of instances. For each instance in the parameter, the getObjectId method is called. This method returns one identity instance for each element in the parameter. The order of iteration of the returned Collection exactly matches the order of iteration of the parameter Collection.
Parameters:
pcs - the persistence-capable instances
Returns:
the object ids of the parameters
Since:
JDO 2.0
See Also:
getObjectId(Object pc)
getObjectIds(Object[] pcs)
Accessor for the state of the passed object.
Accessor for the state of the passed object.
Parameters:
pc - The object
Returns:
The object state
Since:
JDO 2.1
Return the associated PersistenceManager if there is one.
Return the associated PersistenceManager if there is one. Transactional and persistent instances return the associated PersistenceManager.

Transient non-transactional instances and instances of classes that do not implement PersistenceCapable return null.

Parameters:
pc - the PersistenceCapable instance.
Returns:
the PersistenceManager associated with the parameter instance.
Since:
JDO 1.0
See Also:
PersistenceCapable.jdoGetPersistenceManager()
Get the anonymous PersistenceManagerFactory configured via the standard configuration file resource "META-INF/jdoconfig.xml", using the current thread's context class loader to locate the configuration file resource(s).
Get the anonymous PersistenceManagerFactory configured via the standard configuration file resource "META-INF/jdoconfig.xml", using the current thread's context class loader to locate the configuration file resource(s).
Returns:
the anonymous PersistenceManagerFactory.
Since:
JDO 2.1
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
Get a PersistenceManagerFactory based on a Properties instance, using the current thread's context class loader to locate the PersistenceManagerFactory class.
Get a PersistenceManagerFactory based on a Properties instance, using the current thread's context class loader to locate the PersistenceManagerFactory class.
Parameters:
props - a Properties instance with properties of the PersistenceManagerFactory.
Returns:
the PersistenceManagerFactory.
Since:
JDO 1.0
See Also:
getPersistenceManagerFactory(java.util.Map,ClassLoader)
Returns a PersistenceManagerFactory configured based on the properties stored in the file at propsFile.
Returns a PersistenceManagerFactory configured based on the properties stored in the file at propsFile. This method is equivalent to invoking getPersistenceManagerFactory(File,ClassLoader) with Thread.currentThread().getContextClassLoader() as the loader argument.
Parameters:
propsFile - the file containing the Properties
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
Returns a named PersistenceManagerFactory or persistence unit.
Returns a named PersistenceManagerFactory or persistence unit.
Parameters:
name -
Since:
JDO 2.1
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
Returns a named PersistenceManagerFactory or persistence unit.
Returns a named PersistenceManagerFactory or persistence unit.
Parameters:
overrides -
name -
Since:
JDO 2.1
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
Get the anonymous PersistenceManagerFactory configured via the standard configuration file resource "META-INF/jdoconfig.xml", using the given class loader.
Get the anonymous PersistenceManagerFactory configured via the standard configuration file resource "META-INF/jdoconfig.xml", using the given class loader.
Parameters:
pmfClassLoader - the ClassLoader used to load resources and classes
Returns:
the anonymous PersistenceManagerFactory.
Since:
JDO 2.1
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
Returns a PersistenceManagerFactory configured based on the Properties stored in the input stream at stream.
Returns a PersistenceManagerFactory configured based on the Properties stored in the input stream at stream. This method is equivalent to invoking getPersistenceManagerFactory(InputStream,ClassLoader) with Thread.currentThread().getContextClassLoader() as the loader argument.
Parameters:
stream - the stream containing the Properties
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
PersistenceManagerFactory getPersistenceManagerFactory(String jndiLocation, Context context)
Returns a PersistenceManagerFactory at the JNDI location specified by jndiLocation in the context context.
Returns a PersistenceManagerFactory at the JNDI location specified by jndiLocation in the context context. If context is null, new InitialContext() will be used. This method is equivalent to invoking getPersistenceManagerFactory(String,Context,ClassLoader) with Thread.currentThread().getContextClassLoader() as the loader argument.
Parameters:
jndiLocation - the JNDI location containing the PersistenceManagerFactory
context - the context in which to find the named PersistenceManagerFactory
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
PersistenceManagerFactory getPersistenceManagerFactory(Map props, ClassLoader pmfClassLoader)
Get a PersistenceManagerFactory based on a Map and a class loader.
Get a PersistenceManagerFactory based on a Map and a class loader. This method delegates to the getPersistenceManagerFactory method that takes a Map of overrides and a Map of properties, passing null as the overrides parameter.
Parameters:
props - a Map with properties of the PersistenceManagerFactory.
pmfClassLoader - the class loader used to load the PersistenceManagerFactory class
Returns:
the PersistenceManagerFactory.
Since:
JDO 1.0
PersistenceManagerFactory getPersistenceManagerFactory(File propsFile, ClassLoader loader)
Returns a PersistenceManagerFactory configured based on the properties stored in the file at propsFile.
Returns a PersistenceManagerFactory configured based on the properties stored in the file at propsFile. Creates a PersistenceManagerFactory with loader. Any IOExceptions or FileNotFoundExceptions thrown during resource loading will be wrapped in a JDOFatalUserException.
Parameters:
propsFile - the file containing the Properties
loader - the class loader to use to load the PersistenceManagerFactory class
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
PersistenceManagerFactory getPersistenceManagerFactory(String name, ClassLoader loader)
Returns a named PersistenceManagerFactory or persistence unit.
Returns a named PersistenceManagerFactory or persistence unit.
Parameters:
name -
loader -
Since:
JDO 1.0
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
PersistenceManagerFactory getPersistenceManagerFactory(Map overrides, String name, ClassLoader resourceLoader)
Returns a named PersistenceManagerFactory or persistence unit.
Returns a named PersistenceManagerFactory or persistence unit.
Parameters:
overrides -
name -
resourceLoader -
Since:
JDO 2.1
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
PersistenceManagerFactory getPersistenceManagerFactory(InputStream stream, ClassLoader loader)
Returns a PersistenceManagerFactory configured based on the Properties stored in the input stream at stream.
Returns a PersistenceManagerFactory configured based on the Properties stored in the input stream at stream. Creates a PersistenceManagerFactory with loader. Any IOExceptions thrown during resource loading will be wrapped in a JDOFatalUserException.
Parameters:
stream - the stream containing the Properties
loader - the class loader to use to load the PersistenceManagerFactory class
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
PersistenceManagerFactory getPersistenceManagerFactory(String jndiLocation, Context context, ClassLoader loader)
Returns a PersistenceManagerFactory at the JNDI location specified by jndiLocation in the context context.
Returns a PersistenceManagerFactory at the JNDI location specified by jndiLocation in the context context. If context is null, new InitialContext() will be used. Creates a PersistenceManagerFactory with loader. Any NamingExceptions thrown will be wrapped in a JDOFatalUserException.
Parameters:
jndiLocation - the JNDI location containing the PersistenceManagerFactory
context - the context in which to find the named PersistenceManagerFactory
loader - the class loader to use to load the PersistenceManagerFactory class
Returns:
the PersistenceManagerFactory
Since:
JDO 2.0
PersistenceManagerFactory getPersistenceManagerFactory(String name, ClassLoader resourceLoader, ClassLoader pmfLoader)
Returns a named PersistenceManagerFactory or persistence unit.
Returns a named PersistenceManagerFactory or persistence unit.
Parameters:
name -
resourceLoader -
pmfLoader -
Since:
JDO 2.0
See Also:
getPersistenceManagerFactory(Map,String,ClassLoader,ClassLoader)
PersistenceManagerFactory getPersistenceManagerFactory(Map overrides, String name, ClassLoader resourceLoader, ClassLoader pmfLoader)
Returns a PersistenceManagerFactory configured based on the properties stored in the resource at name, or, if not found, returns a PersistenceManagerFactory with the given name or, if not found, returns a javax.persistence.EntityManagerFactory cast to a PersistenceManagerFactory.
Returns a PersistenceManagerFactory configured based on the properties stored in the resource at name, or, if not found, returns a PersistenceManagerFactory with the given name or, if not found, returns a javax.persistence.EntityManagerFactory cast to a PersistenceManagerFactory. If the name given is null or consists only of whitespace, it is interpreted as Constants.ANONYMOUS_PERSISTENCE_MANAGER_FACTORY_NAME. The following are standard key names:
"javax.jdo.PersistenceManagerFactoryClass"
"javax.jdo.option.Optimistic",
"javax.jdo.option.RetainValues",
"javax.jdo.option.RestoreValues",
"javax.jdo.option.IgnoreCache",
"javax.jdo.option.NontransactionalRead",
"javax.jdo.option.NontransactionalWrite",
"javax.jdo.option.Multithreaded",
"javax.jdo.option.ConnectionUserName",
"javax.jdo.option.ConnectionPassword",
"javax.jdo.option.ConnectionURL",
"javax.jdo.option.ConnectionFactoryName",
"javax.jdo.option.ConnectionFactory2Name",
"javax.jdo.option.Mapping",
"javax.jdo.mapping.Catalog",
"javax.jdo.mapping.Schema",
"javax.jdo.option.PersistenceUnitName".
"javax.jdo.option.DetachAllOnCommit".
"javax.jdo.option.CopyOnAttach".
"javax.jdo.option.TransactionType".
"javax.jdo.option.ServerTimeZoneID".
"javax.jdo.option.Name".
and properties of the form
javax.jdo.option.InstanceLifecycleListener.{listenerClass}[=[{pcClasses}]] where {listenerClass} is the fully qualified name of a class that implements javax.jdo.listener.InstanceLifecycleListener, and {pcClasses} is an optional comma- or whitespace-delimited list of persistence-capable classes to be observed; the absence of a value for a property of this form means that instances of all persistence-capable classes will be observed by an instance of the given listener class.

JDO implementations are permitted to define key values of their own. Any key values not recognized by the implementation must be ignored. Key values that are recognized but not supported by an implementation must result in a JDOFatalUserException thrown by the method.

The returned PersistenceManagerFactory is not configurable (the setXXX methods will throw an exception). This method loads the properties found at name, if any, via resourceLoader, and creates a PersistenceManagerFactory with pmfLoader. Any exceptions thrown during resource loading will be wrapped in a JDOFatalUserException. If multiple PMFs with the requested name are found, a JDOFatalUserException is thrown.

Parameters:
overrides - a Map containing properties that override properties defined in any resources loaded according to the "name" parameter
name - interpreted as the name of the resource containing the PMF properties, the name of the PMF, or the persistence unit name, in that order; if name is null, blank or whitespace, it is interpreted as indicating the anonymous PersistenceManagerFactory.
resourceLoader - the class loader to use to load properties file resources; must be non-null if name is non-null or blank
pmfLoader - the class loader to use to load the PersistenceManagerFactory or javax.persistence.EntityManagerFactory classes
Returns:
the PersistenceManagerFactory with properties in the given resource, with the given name, or with the given persitence unit name
Since:
JDO 2.1
See Also:
Constants.ANONYMOUS_PERSISTENCE_MANAGER_FACTORY_NAME
Object getTransactionalObjectId(Object pc)
Return a copy of the JDO identity associated with the parameter instance.
Return a copy of the JDO identity associated with the parameter instance.
Parameters:
pc - the PersistenceCapable instance.
Returns:
a copy of the ObjectId of the parameter instance as modified in this transaction.
Since:
JDO 1.0
See Also:
PersistenceCapable.jdoGetTransactionalObjectId()
PersistenceManager.getObjectById(Object oid, boolean validate)
Object getVersion(Object pc)
Return the version of the instance.
Return the version of the instance.
Parameters:
pc - the instance
Returns:
the version of the instance
Since:
JDO 2.0
boolean isDeleted(Object pc)
Tests whether the parameter instance has been deleted.
Tests whether the parameter instance has been deleted. Instances that have been deleted in the current transaction return true.

Transient instances and instances of classes that do not implement PersistenceCapable return false.

Parameters:
pc - the PersistenceCapable instance.
Returns:
true if the parameter instance was deleted in the current transaction.
Since:
JDO 1.0
See Also:
PersistenceManager.deletePersistent(Object pc)
PersistenceCapable.jdoIsDeleted()
boolean isDetached(Object pc)
Tests whether the parameter instance has been detached.
Tests whether the parameter instance has been detached. Instances that have been detached return true.

Transient instances return false.

Parameters:
pc - the instance
Returns:
true if this instance is detached.
Since:
JDO 2.0
See Also:
PersistenceCapable.jdoIsDetached()
boolean isDirty(Object pc)
Tests whether the parameter instance is dirty.
Tests whether the parameter instance is dirty. Instances that have been modified, deleted, or newly made persistent in the current transaction return true.

Transient instances and instances of classes that do not implement PersistenceCapable return false.

Parameters:
pc - the PersistenceCapable instance.
Returns:
true if the parameter instance has been modified in the current transaction.
Since:
JDO 1.0
See Also:
javax.jdo.spi.StateManager.makeDirty(PersistenceCapable pc, String fieldName)
PersistenceCapable.jdoIsDirty()
boolean isNew(Object pc)
Tests whether the parameter instance has been newly made persistent.
Tests whether the parameter instance has been newly made persistent. Instances that have been made persistent in the current transaction return true.

Transient instances and instances of classes that do not implement PersistenceCapable return false.

Parameters:
pc - the PersistenceCapable instance.
Returns:
true if the parameter instance was made persistent in the current transaction.
Since:
JDO 1.0
See Also:
PersistenceManager.makePersistent(Object pc)
PersistenceCapable.jdoIsNew()
boolean isPersistent(Object pc)
Tests whether the parameter instance is persistent.
Tests whether the parameter instance is persistent. Instances that represent persistent objects in the data store return true.

Transient instances and instances of classes that do not implement PersistenceCapable return false.

Parameters:
pc - the PersistenceCapable instance.
Returns:
true if the parameter instance is persistent.
Since:
JDO 1.0
See Also:
PersistenceManager.makePersistent(Object pc)
PersistenceCapable.jdoIsPersistent()
boolean isTransactional(Object pc)
Tests whether the parameter instance is transactional.
Tests whether the parameter instance is transactional. Instances whose state is associated with the current transaction return true.

Transient instances and instances of classes that do not implement PersistenceCapable return false.

Parameters:
pc - the PersistenceCapable instance.
Returns:
true if the parameter instance is transactional.
Since:
JDO 1.0
See Also:
PersistenceCapable.jdoIsTransactional()
void makeDirty(Object pc, String fieldName)
Explicitly mark the parameter instance and field dirty.
Explicitly mark the parameter instance and field dirty. Normally, PersistenceCapable classes are able to detect changes made to their fields. However, if a reference to an array is given to a method outside the class, and the array is modified, then the persistent instance is not aware of the change. This API allows the application to notify the instance that a change was made to a field.

Transient instances and instances of classes that do not implement PersistenceCapable ignore this method.

Parameters:
pc - the PersistenceCapable instance.
fieldName - the name of the field to be marked dirty.
Since:
JDO 1.0
See Also:
PersistenceCapable.jdoMakeDirty(String fieldName)

This documentation page is derived (with some adjustments) from the JDO 2.2 API
and is available under the terms of the Apache License, v. 2.0.