With the EJB specifications, the following methods can invoke the EntityManager methods in the Stateful Session Bean: Life cycle callback method PostConstruct and PreDestroy Business method of the business interface or component interface Business method Interceptor method afterBegin and beforeCompletion methods of SessionSynchronization The EntityManager methods cannot be invoked with the constructor, the setter method of the DI, and afterCompletion method of SessionSynchronization.
If you use the getDelegate method of this proxy class, you can obtain the EntityManager object provided by the JPA provider. However, when the container-managed EntityManager is used, the container manages the EntityManager life cycle, so do not invoke the close method of the EntityManager object obtained by using the getDelegate method, from the application. If the getDelegate method of EntityManager is invoked when the transaction scope persistence context is used and when transaction does not exist, the container cannot close the returned EntityManager.
In this case, you must invoke EntityManager. Let us consider employee management as example. It means the employee management is creating, updating, finding, and deleting an employee.
As mentioned above we are using MySQL database for database operations. Let us take the package hierarchy which we have used in the JPA installation with Eclipselink. Follow the hierarchy for this example as below:.
Entities are nothing but beans or Models, in this example we will use Employee as entity. It contains default constructor, setter and getter methods of those attributes. Create a class named Employee. Before going to next module we need to create database for relational entity, which will register the database in persistence.
The resultClass arguments must be specified in the order in which the result sets will be returned by the stored procedure invocation. Parameters: procedureName - name of the stored procedure in the database resultClasses - classes to which the result sets produced by the stored procedure are to be mapped Returns: the new stored procedure query instance Throws: IllegalArgumentException - if a stored procedure of the given name does not exist or the query execution will fail Since: Java Persistence 2.
The resultSetMapping arguments must be specified in the order in which the result sets will be returned by the stored procedure invocation. Parameters: procedureName - name of the stored procedure in the database resultSetMappings - the names of the result set mappings to be used in mapping result sets returned by the stored procedure Returns: the new stored procedure query instance Throws: IllegalArgumentException - if a stored procedure or result set mapping of the given name does not exist or the query execution will fail joinTransaction void joinTransaction Indicate to the entity manager that a JTA transaction is active and join the persistence context to it.
This method should be called on a JTA application managed entity manager that was created outside the scope of the active transaction or on an entity manager of type SynchronizationType.
Throws: TransactionRequiredException - if there is no transaction isJoinedToTransaction boolean isJoinedToTransaction Determine whether the entity manager is joined to the current transaction. Returns false if the entity manager is not joined to the current transaction or if no transaction is active Returns: boolean Since: Java Persistence 2. If the provider's EntityManager implementation does not support the specified class, the PersistenceException is thrown.
Parameters: cls - the class of the object to be returned. This is normally either the underlying EntityManager implementation class or an interface that it implements. Returns: an instance of the specified class Throws: PersistenceException - if the provider does not support the call Since: Java Persistence 2.
The result of this method is implementation specific. The unwrap method is to be preferred for new applications. Returns: underlying provider object for EntityManager close void close Close an application-managed entity manager. After the close method has been invoked, all methods on the EntityManager instance and any Query , TypedQuery , and StoredProcedureQuery objects obtained from it will throw the IllegalStateException except for getProperties , getTransaction , and isOpen which will return false.
If this method is called when the entity manager is joined to an active transaction, the persistence context remains managed until the transaction completes. Throws: IllegalStateException - if the entity manager is container-managed isOpen boolean isOpen Determine whether the entity manager is open.
Returns: true until the entity manager has been closed getTransaction EntityTransaction getTransaction Return the resource-level EntityTransaction object. The EntityTransaction instance may be used serially to begin and commit multiple transactions.
If there is no entity graph with the specified name, null is returned. The returned EntityGraph should be considered immutable. Parameters: entityClass - entity class Returns: list of all entity graphs defined for the entity Throws: IllegalArgumentException - if the class is not an entity Since: Java Persistence 2.
All Rights Reserved. Use is subject to license terms. Skip navigation links. Check if the instance is a managed entity instance belonging to the current persistence context. Return a mutable EntityGraph that can be used to dynamically create an EntityGraph.
Create an instance of TypedQuery for executing a Java Persistence query language named query. Create an instance of StoredProcedureQuery for executing a stored procedure in the database. Create an instance of Query for executing a native SQL statement, e.
You should use PersistenceContext instead Autowired. Please go through this question stackoverflow. Add a comment. Active Oldest Votes. Improve this answer. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Explaining the semiconductor shortage, and how it might end.
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