001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.oozie.executor.jpa; 020 021import javax.persistence.EntityManager; 022 023/** 024 * Executor pattern interface that gives access to an {@link EntityManager}. 025 * <p> 026 * Implementations are executed by the {@link org.apache.oozie.service.JPAService}. 027 */ 028public interface JPAExecutor<T> { 029 030 /** 031 * Return the name of the JPA executor. Used for logging and instrumentation. 032 * 033 * @return the name of the JPA executor. 034 */ 035 String getName(); 036 037 /** 038 * Method that encapsulates JPA access operations. 039 * <p> 040 * Implementations should not close the received {@link EntityManager}. 041 * <p> 042 * Implementations should commit any transaction before ending, else the transaction will be rolled back. 043 * 044 * @param em an active {@link EntityManager} 045 * @return a return value if any. 046 * @throws JPAExecutorException thrown if a jpa executor failed 047 */ 048 T execute(EntityManager em) throws JPAExecutorException; 049 050}