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Java example source code file (EntityManagerProvisionTest.java)

This example Java source code file (EntityManagerProvisionTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

duplicate, entitymanager, entitymanagerprovisiontest, injector, jpadao, jpapersistmodule, jpatestentity, persisting, provider, testcase, transactional

The EntityManagerProvisionTest.java Java example source code

/**
 * Copyright (C) 2010 Google, Inc.
 *
 * 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 com.google.inject.persist.jpa;

import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Provider;
import com.google.inject.persist.PersistService;
import com.google.inject.persist.Transactional;

import junit.framework.TestCase;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

/**
 * A test around providing sessions (starting, closing etc.)
 *
 * @author Dhanji R. Prasanna (dhanji@gmail.com)
 */

public class EntityManagerProvisionTest extends TestCase {
  private Injector injector;

  public void setUp() {
    injector = Guice.createInjector(new JpaPersistModule("testUnit"));

    //startup persistence
    injector.getInstance(PersistService.class).start();
  }

  public final void tearDown() {
    injector.getInstance(EntityManagerFactory.class).close();
  }

  public void testEntityManagerLifecyclePerTxn() {
    //obtain em
    JpaDao dao = injector.getInstance(JpaDao.class);

    //obtain same em again (bound to txn)
    JpaTestEntity te = new JpaTestEntity();

    dao.persist(te);

    //im not sure this hack works...
    assertFalse("Duplicate entity managers crossing-scope",
        dao.lastEm.equals(injector.getInstance(EntityManager.class)));

    //try to start a new em in a new txn
    dao = injector.getInstance(JpaDao.class);

    assertFalse("EntityManager wasnt closed and reopened properly around txn"
        + " (persistent object persists)", dao.contains(te));
  }

  public void testEntityManagerLifecyclePerTxn2() {
    //obtain em
    JpaDao dao = injector.getInstance(JpaDao.class);

    //obtain same em again (bound to txn)
    JpaTestEntity te = new JpaTestEntity();

    dao.persist(te);

    //im not sure this hack works...
    assertFalse("Duplicate entity managers crossing-scope",
        dao.lastEm.equals(injector.getInstance(EntityManager.class)));

    //try to start a new em in a new txn
    dao = injector.getInstance(JpaDao.class);

    assertFalse("EntityManager wasnt closed and reopened properly around txn"
        + " (persistent object persists)", dao.contains(te));
  }

  public static class JpaDao {
    private final Provider<EntityManager> em;
    EntityManager lastEm;

    @Inject
    public JpaDao(Provider<EntityManager> em) {
     this.em = em;
    }

    @Transactional
    public <T> void persist(T t) {
      lastEm = em.get();
      assertTrue("em is not open!", lastEm.isOpen());
      assertTrue("no active txn!", lastEm.getTransaction().isActive());
      lastEm.persist(t);

      assertTrue("Persisting object failed", lastEm.contains(t));
    }

    @Transactional
    public <T> boolean contains(T t) {
      if (null == lastEm) {
        lastEm = em.get();
      }
      return lastEm.contains(t);
    }
  }
}

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