org.springframework.orm.jpa.JpaCallback Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.orm.jpa;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceException;
/**
* Callback interface for JPA code. To be used with {@link JpaTemplate}'s
* execution method, often as anonymous classes within a method implementation.
* A typical implementation will call EntityManager.find/merge
* to perform some operations on persistent objects.
*
* @author Juergen Hoeller
* @since 2.0
* @see org.springframework.orm.jpa.JpaTemplate
* @see org.springframework.orm.jpa.JpaTransactionManager
*/
public interface JpaCallback {
/**
* Gets called by JpaTemplate.execute with an active
* JPA EntityManager. Does not need to care about activating
* or closing the EntityManager, or handling transactions.
*
* Note that JPA callback code will not flush any modifications to the
* database if not executed within a transaction. Thus, you need to make
* sure that JpaTransactionManager has initiated a JPA transaction when
* the callback gets called, at least if you want to write to the database.
*
*
Allows for returning a result object created within the callback,
* i.e. a domain object or a collection of domain objects.
* A thrown custom RuntimeException is treated as an application exception:
* It gets propagated to the caller of the template.
*
* @param em active EntityManager
* @return a result object, or null if none
* @throws PersistenceException if thrown by the JPA API
* @see org.springframework.orm.jpa.JpaTemplate#execute
* @see org.springframework.orm.jpa.JpaTemplate#executeFind
*/
Object doInJpa(EntityManager em) throws PersistenceException;
}