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.
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 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
of an entity belonging to the persistence unit.
- Parameters:
entity- entity instance containing the attributeattributeName- 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)
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, String attributeName)
Determine the load state of a given persistent attribute.
- Parameters:
entity- entity containing the attributeattributeName- 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.
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.
Which JPA is Faster?
See a comparison of Hibernate, EclipseLink, OpenJPA, DataNucleus, MySQL, PostgreSQL, Derby, HSQLDB, DB4O by Versant, H2 Database, SQLite and ObjectDB
in the JPA Benchmark.
