| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.openjpa.persistence.spring; |
| |
| import javax.persistence.EntityManager; |
| import javax.persistence.EntityTransaction; |
| import javax.persistence.Query; |
| |
| import org.apache.openjpa.persistence.models.library.Book; |
| import org.apache.openjpa.persistence.models.library.Borrower; |
| |
| /** |
| * This service uses a transactionally scoped entity manager. It grabs the EM at |
| * the beginning of each business method and closes it at the end of each |
| * business method. Transactional methods start a transaction and either commit |
| * or roll back at the end of the method. This behavior mimics the behavior of |
| * containers that inject transactionally scoped entity managers at the |
| * beginning of each service method and close them at the end. |
| */ |
| public class LibServiceImpl implements LibService { |
| private TransactionalEntityManagerFactory txEMF; |
| |
| private void closeEM(EntityManager em) { |
| if (em != null && em.isOpen()) { |
| em.close(); |
| } |
| } |
| |
| private EntityManager openEM() { |
| EntityManager em = txEMF.getTransactionalEntityManager(); |
| return em; |
| } |
| |
| private void commit(EntityTransaction tx) { |
| if (tx != null && tx.isActive()) { |
| if (tx.getRollbackOnly()) |
| tx.rollback(); |
| else |
| tx.commit(); |
| } |
| } |
| |
| @Override |
| public void setTransactionalEntityManagerFactory( |
| TransactionalEntityManagerFactory txEMF) { |
| this.txEMF = txEMF; |
| } |
| |
| @Override |
| public Book findBookByTitle(String title) { |
| EntityManager em = null; |
| |
| try { |
| em = openEM(); |
| |
| // check the name passed in |
| if (title != null) |
| title = title.trim(); |
| |
| if (title == null || title.length() <= 0) |
| throw new IllegalArgumentException( |
| "the title cannot be null or empty"); |
| |
| // set up the query |
| Query query = em.createQuery( |
| "select b from Book b join fetch b.subjects where b.title = :x"); |
| query.setParameter("x", title); |
| |
| // execute the query and return the books |
| Book retv = (Book) query.getSingleResult(); |
| return retv; |
| } finally { |
| closeEM(em); |
| } |
| } |
| |
| @Override |
| public Borrower findBorrowerByName(String name) { |
| EntityManager em = null; |
| |
| try { |
| em = openEM(); |
| |
| // check the name passed in |
| if (name != null) |
| name = name.trim(); |
| |
| if (name == null || name.length() <= 0) |
| throw new IllegalArgumentException( |
| "the name cannot be null or empty"); |
| |
| // set up the query |
| Query query = em |
| .createQuery("select b from Borrower b where b.name = :x"); |
| query.setParameter("x", name); |
| |
| // execute the query and return the books |
| Borrower retv = (Borrower) query.getSingleResult(); |
| return retv; |
| } finally { |
| closeEM(em); |
| } |
| } |
| |
| @Override |
| public void borrowBook(Borrower borrower, Book book) { |
| EntityManager em = null; |
| EntityTransaction tx = null; |
| |
| try { |
| em = openEM(); |
| tx = em.getTransaction(); |
| tx.begin(); |
| |
| // do nothing if one of the parameters is null |
| if (borrower == null || book == null) |
| return; |
| |
| borrower.borrowBook(book); |
| |
| // merge the owner of the relationship |
| em.merge(book); |
| } catch (RuntimeException e) { |
| tx.setRollbackOnly(); |
| throw e; |
| } finally { |
| commit(tx); |
| closeEM(em); |
| } |
| } |
| |
| @Override |
| public void returnBook(Book book) { |
| EntityManager em = null; |
| EntityTransaction tx = null; |
| |
| try { |
| em = openEM(); |
| tx = em.getTransaction(); |
| tx.begin(); |
| |
| // do nothing if the parameter is null |
| if (book == null) |
| return; |
| |
| Borrower borrower = book.getBorrower(); |
| if (borrower != null) { |
| borrower.returnBook(book); |
| |
| // merge the owner of the relationship |
| em.merge(book); |
| } |
| } catch (RuntimeException e) { |
| tx.setRollbackOnly(); |
| throw e; |
| } finally { |
| commit(tx); |
| closeEM(em); |
| } |
| } |
| } |