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oracle.toplink.sessions.entitymanager
Interface EntityManager

All Known Subinterfaces:

EntityManager

public interface EntityManager

Interface used to interact with the persistence context.

Method Summary

void	close() Closes this EntityManager.
boolean	contains(java.lang.Object entity) Check if the instance belongs to the current persistence context.
Query	createNamedQuery(java.lang.String name) Create an instance of Query for executing a named query (in EJBQL or native SQL).
Query	createNativeQuery(java.lang.String sqlString) Create an instance of Query for executing a native SQL query.
Query	createNativeQuery(java.lang.String sqlString, java.lang.Class resultClass) Create an instance of Query for executing a native SQL query.
Query	createNativeQuery(java.lang.String sqlString, java.lang.String resultSetMapping) Create an instance of Query for executing a native SQL query.
Query	createQuery(java.lang.String ejbqlString) Create an instance of Query for executing an EJBQL query.
java.lang.Object	find(java.lang.Class entityClass, java.lang.Object primaryKey) Find by primary key.
java.lang.Object	find(java.lang.String entityName, java.lang.Object primaryKey) Find by primary key.
void	flush() Synchronize the persistence context with the underlying database.
EntityTransaction	getUserTransaction() Looks up the current user transaction.
boolean	isOpen() Indicates whether or not this entity manager is open.
java.lang.Object	merge(java.lang.Object entity) Merge the state of the given entity into the current persistence context, using the unqualified class name as the entity name.
void	persist(java.lang.Object entity) Make an instance managed, using the unqualified class name as the entity name.
void	refresh(java.lang.Object entity) Refresh the state of the instance from the database.
void	remove(java.lang.Object entity) Remove the instance.

Method Detail

persist

public void persist(java.lang.Object entity)

Make an instance managed, using the unqualified class name as the entity name.

Parameters:

entity -

merge

public java.lang.Object merge(java.lang.Object entity)

Merge the state of the given entity into the current persistence context, using the unqualified class name as the entity name.

Parameters:

entity -

Returns:

the instance that the state was merged to jdk14

remove

public void remove(java.lang.Object entity)

Remove the instance.

Parameters:

entity -

refresh

public void refresh(java.lang.Object entity)

Refresh the state of the instance from the database.

Parameters:

entity -

Throws:

java.lang.IllegalArgumentException - if not an entity or entity is not in managed state

TransactionRequiredException - if there is no transaction

find

public java.lang.Object find(java.lang.String entityName,
                             java.lang.Object primaryKey)

Find by primary key.

Parameters:

entityName -

primaryKey -

Returns:

the found entity instance

find

public java.lang.Object find(java.lang.Class entityClass,
                             java.lang.Object primaryKey)

Find by primary key.

Parameters:

entityClass -

primaryKey -

Returns:

the found entity instance jdk14

flush

public void flush()

Synchronize the persistence context with the underlying database.

createQuery

public Query createQuery(java.lang.String ejbqlString)

Create an instance of Query for executing an EJBQL query.

Parameters:

ejbqlString - an EJBQL query string

Returns:

the new query instance

createNamedQuery

public Query createNamedQuery(java.lang.String name)

Create an instance of Query for executing a named query (in EJBQL or native SQL).

Parameters:

name - the name of a query defined in metadata

Returns:

the new query instance

createNativeQuery

public Query createNativeQuery(java.lang.String sqlString)

Create an instance of Query for executing a native SQL query. Warning: Allowing an unverified SQL string to be passed into this method makes your application vulnerable to SQL injection attacks.

Parameters:

sqlString - a native SQL query string

Returns:

the new query instance

createNativeQuery

public Query createNativeQuery(java.lang.String sqlString,
                               java.lang.Class resultClass)

Create an instance of Query for executing a native SQL query.

Parameters:

sqlString - a native SQL query string

resultClass - the class of the resulting instances

Returns:

the new query instance

Throws:

java.lang.IllegalArgumentException - if query string is not valid

createNativeQuery

public Query createNativeQuery(java.lang.String sqlString,
                               java.lang.String resultSetMapping)

Create an instance of Query for executing a native SQL query. Warning: Allowing an unverified SQL string to be passed into this method makes your application vulnerable to SQL injection attacks.

Parameters:

sqlString - a native SQL query string

resultSetMapping - the name of the result set mapping

Returns:

the new query instance

Throws:

java.lang.IllegalArgumentException - if query string is not valid

contains

public boolean contains(java.lang.Object entity)

Check if the instance belongs to the current persistence context.

Parameters:

entity -

Returns:

close

public void close()

Closes this EntityManager. This can only be called when the transaction that this EntityManager is associated with has a status of Status#STATUS_NO_TRANSACTION, Status#Status_COMMITTED or Status#STATUS_ROLLEDBACK. It will throw an IllegalStateException if invoked when this condition is not true.

After invoking this method, all methods on the instance will throw an IllegalStateException except for isOpen(), which will return false .

This should be called when a method is finished with the EntityManager in a bean-managed transaction environment or when executed outside a container. Closing of the EntityManager is handled by the container when using container-managed transactions.

isOpen

public boolean isOpen()

Indicates whether or not this entity manager is open. Returns true until a call to close() is made.

getUserTransaction

public EntityTransaction getUserTransaction()

Looks up the current user transaction. This may cause an exception to be raised if a UserTransaction is not accessible. If outside a managed environment, JTA semantics are emulated.

This always returns a UserTransaction when outside a container and equates to a simple JNDI lookup on the UserTransaction when inside the Container. The returned UserTransaction may or may not be a proxy around the actual object.

Inside a container, the EM will use the TransactionManager as a means to synchronize, but outside the Container the EM is tightly coupled with (essentially it implements) the TransactionManager.

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