org.perfectjpattern.jee.api.integration.dao
Interface ISession

public interface ISession

Abstract definition of Session available for the DAO implementation. The DAO API exposes this interface but it will be automatically adapted from the underlying JPA-specific implementation (see IAdapter).

JPA and specific implementations define similar abstractions e.g. Session vs EntityManager but despite their similarities, their types actually mismatch making it difficult to provide a generic unified DAO solution.

Note that this is a subset of the functionality that the underlying implementation offers. This is the subset required to make the DAO portable. If required, it is possible to get the underlying implementation using getDelegate()

Version:

$Revision: 1.0 $Date: Feb 10, 2009 5:47:08 PM $

Author:

Giovanni Azua

Method Summary

void	clear() Clears the Session, removing all cached changes without applying them.
void	close() Closes the Session.
boolean	contains(Object anEntity) Returns true if the instance belongs to the current persistence context, false otherwise
IQuery	createNativeQuery(String aSqlString, Class<?> aPersistentClass) Returns instance of JPA implementation-specific Query for executing native SQL queries.
IQuery	createQuery(String aSqlString) Returns instance of JPA implementation-specific Query for executing JPA-specific Queries e.g.
<E> E	find(Class<E> aPersistentClass, Object anId) Returns the Entity instance if found, null if the entity does not exist
void	flush() Flushes the Session by applying all cached changes to the persistent store.
<S> S	getDelegate() Returns the implementation-specific Session
ITransaction	getTransaction() Returns the ITransaction adapted from the implementation-specific
<Id> Id	persist(Object anObject) Returns the Id of the newly persisted Object.
void	refresh(Object anObject) Refresh the state of the instance from the database, overwriting changes made to the entity, if any
void	remove(Object anObject) Removes Object from the persistent store
void	update(Object anObject) Updates the Object in the persistent store

Method Detail

clear

void clear()
           throws DaoException

Clears the Session, removing all cached changes without applying them. The underlying implementation is JPA implementation- specific.

Throws:

DaoException

close

void close()
           throws DaoException

Closes the Session. The underlying implementation is JPA implementation-specific.

Throws:

DaoException

flush

void flush()
           throws DaoException

Flushes the Session by applying all cached changes to the persistent store. The underlying implementation is JPA implementation- specific.

Throws:

DaoException

contains

boolean contains(Object anEntity)

Returns true if the instance belongs to the current persistence context, false otherwise

Parameters:

anEntity - The entity to check

Returns:

true if the instance belongs to the current persistence context, false otherwise

find

<E> E find(Class<E> aPersistentClass,
           Object anId)

Returns the Entity instance if found, null if the entity does not exist

Type Parameters:

E -

Parameters:

aPersistentClass - Persistent class

anId - The Id to look for

Returns:

Entity instance if found, null if the entity does not exist

getTransaction

ITransaction getTransaction()

Returns the ITransaction adapted from the implementation-specific

Returns:

ITransaction adapted from the implementation-specific

See Also:

IAdapter

remove

void remove(Object anObject)

Removes Object from the persistent store

Parameters:

anObject - The Object to remove

persist

<Id> Id persist(Object anObject)

Returns the Id of the newly persisted Object. Creates the Object in the persistent store. Note that not all adapted implementations will return an Id e.g. adapted Hibernate does but using pure JPA will not.

Parameters:

anObject - The Object to persist

Returns:

Id of the newly persisted Object

update

void update(Object anObject)

Updates the Object in the persistent store

Parameters:

anObject - The Object to update

refresh

void refresh(Object anObject)

Refresh the state of the instance from the database, overwriting changes made to the entity, if any

Parameters:

anObject - The Object to refresh

createQuery

IQuery createQuery(String aSqlString)

Returns instance of JPA implementation-specific Query for executing JPA-specific Queries e.g. HQL queries.

Parameters:

aSqlString - SQL query input

Returns:

instance of JPA implementation-specific Query

createNativeQuery

IQuery createNativeQuery(String aSqlString,
                         Class<?> aPersistentClass)

Returns instance of JPA implementation-specific Query for executing native SQL queries.

Parameters:

aSql - SQL query input

Returns:

instance of JPA implementation-specific Query

getDelegate

<S> S getDelegate()

Returns the implementation-specific Session

Returns:

implementation-specific Session