461 words

javax.persistence.PersistenceUnitUtil - JPA interface

javax.persistence
Interface PersistenceUnitUtil

Superinterfaces:
PersistenceUtil
Utility interface between the application and the persistence provider managing the persistence unit.

The methods of this interface should only be invoked on entity instances obtained from or managed by entity managers for this persistence unit or on new entity instances.

Since:
JPA 2.0
Object getIdentifier(Object entity)
Return the id of the entity.
Return the id of the entity. A generated id is not guaranteed to be available until after the database insert has occurred. Returns null if the entity does not yet have an id.
Parameters:
entity - entity instance
Returns:
id of the entity
Throws:
IllegalArgumentException - if the object is found not to be an entity
Since:
JPA 2.0
boolean isLoaded(Object entity)
Determine the load state of an entity.
Determine the load state of an entity. This method can be used to determine the load state of an entity passed as a reference. An entity is considered loaded if all attributes for which FetchType.EAGER has been specified have been loaded.

The isLoaded(Object, String) method should be used to determine the load state of an attribute. Not doing so might lead to unintended loading of state.

Parameters:
entity - whose load state is to be determined
Returns:
false if the entity has not been loaded, else true
Since:
JPA 2.0
boolean isLoaded(Object entity)
Determine the load state of an entity belonging to the persistence unit.
Determine the load state of an entity belonging to the persistence unit. This method can be used to determine the load state of an entity passed as a reference. An entity is considered loaded if all attributes for which FetchType.EAGER has been specified have been loaded.

The isLoaded(Object, String) method should be used to determine the load state of an attribute. Not doing so might lead to unintended loading of state.

Parameters:
entity - entity instance whose load state is to be determined
Returns:
false if the entity has not been loaded, else true
Since:
JPA 2.0
boolean isLoaded(Object entity, String attributeName)
Determine the load state of a given persistent attribute.
Determine the load state of a given persistent attribute.
Parameters:
entity - entity containing the attribute
attributeName - name of attribute whose load state is to be determined
Returns:
false if entity's state has not been loaded or if the attribute state has not been loaded, else true
Since:
JPA 2.0
boolean isLoaded(Object entity, String attributeName)
Determine the load state of a given persistent attribute of an entity belonging to the persistence unit.
Determine the load state of a given persistent attribute of an entity belonging to the persistence unit.
Parameters:
entity - entity instance containing the attribute
attributeName - name of attribute whose load state is to be determined
Returns:
false if entity's state has not been loaded or if the attribute state has not been loaded, else true
Since:
JPA 2.0

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.