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/* Copyright (c) 2008-2009, Frank Schwarz <frank.schwarz@buschmais.com>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met:
 *    * Redistributions of source code must retain the 
 *      above copyright notice, this list of conditions 
 *      and the following disclaimer.
 *    * Redistributions in binary form must reproduce 
 *      the above copyright notice, this list of 
 *      conditions and the following disclaimer in the 
 *      documentation and/or other materials provided 
 *      with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 
 * DAMAGE. 
 */
package oopex.eclipselink1.jpa.queries;

import java.util.Collection;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

import oopex.eclipselink1.jpa.queries.model.ForProfitCompany;
import oopex.eclipselink1.jpa.queries.model.NonProfitCompany;
import oopex.eclipselink1.jpa.queries.model.Person;

import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.expressions.Expression;
import org.eclipse.persistence.expressions.ExpressionBuilder;
import org.eclipse.persistence.internal.helper.DatabaseField;
import org.eclipse.persistence.jpa.JpaEntityManager;
import org.eclipse.persistence.mappings.ObjectReferenceMapping;
import org.eclipse.persistence.mappings.querykeys.OneToOneQueryKey;
import org.eclipse.persistence.queries.ReadAllQuery;
import org.eclipse.persistence.sessions.Session;

public class DowncastsMain {

	public static void main(String[] args) {

		EntityManagerFactory entityManagerFactory = Persistence
				.createEntityManagerFactory("default");
		try {
			System.out.println("*** insert ***");
			insert(entityManagerFactory);
			System.out.println("*** query with JPQL ***");
			querywithjpql(entityManagerFactory);
			System.out.println("*** query with criteria ***");
			querywithcriteria(entityManagerFactory);
			System.out.println("*** query with query keys ***");
			querywithquerykeys(entityManagerFactory);
			System.out.println("*** delete ***");
			delete(entityManagerFactory);
		} finally {
			entityManagerFactory.close();
			System.out.println("*** finished ***");
		}
	}

	private static void insert(EntityManagerFactory entityManagerFactory) {
		EntityManager entityManager = entityManagerFactory
				.createEntityManager();
		try {
			entityManager.getTransaction().begin();
			Person person1 = new Person("Carla Peters");
			Person person2 = new Person("John Reader");
			
			NonProfitCompany company1 = new NonProfitCompany("Cats in need", "animal wellfare");
			ForProfitCompany company2 = new ForProfitCompany("Oil Ltd.", "oil production");
			
			person1.setEmployer(company1);
			person2.setEmployer(company2);
			
			entityManager.persist(person1);
			entityManager.persist(person2);

			entityManager.getTransaction().commit();
		} finally {
			if (entityManager.getTransaction().isActive()) {
				entityManager.getTransaction().rollback();
			}
			entityManager.close();
		}
	}

	@SuppressWarnings("unchecked")
	public static void querywithjpql(EntityManagerFactory entityManagerFactory) {
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		try {
			//SELECT p FROM Person p WHERE TYPE(p.company) = ForProfitCompany AND ((ForProfitCompany)p.company).sector LIKE '%oil%'
			Query query = entityManager.createQuery("SELECT p FROM Person p, ForProfitCompany company WHERE company.sector LIKE '%oil%' AND p.employer = company");
			List<Person> list = query.getResultList();
			for (Person person : list) {
				System.out.println(String.format("result: [%s, employer: [%s]]", person, person.getEmployer()));
			}
		} finally {
			entityManager.close();
		}
	}

	@SuppressWarnings("unchecked")
	public static void querywithcriteria(EntityManagerFactory entityManagerFactory) {
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		try {
			final Session session = ((JpaEntityManager)entityManager).getSession();
			ReadAllQuery query = new ReadAllQuery(Person.class);
			ExpressionBuilder personE = query.getExpressionBuilder();
			ExpressionBuilder forProfitCompanyE = new ExpressionBuilder(ForProfitCompany.class);
			Expression join = personE.get("employer").equal(forProfitCompanyE);
			query.setSelectionCriteria(join.and(forProfitCompanyE.get("sector").like("%oil%")));
			Collection<Person> collection = (Collection<Person>) session.executeQuery(query);
			for (Person person : collection) {
				System.out.println(String.format("result: [%s, employer: [%s]]", person, person.getEmployer()));
			}
		} finally {
			entityManager.close();
		}
	}

	@SuppressWarnings("unchecked")
	public static void querywithquerykeys(EntityManagerFactory entityManagerFactory) {
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		try {
			final Session session = ((JpaEntityManager)entityManager).getSession();
			{
				// establish a (persistent!) one-to-one-query-key from Person to ForProfitCompany as profitCompanyEmployer
				ClassDescriptor personDescriptor = session.getDescriptor(Person.class);
				ObjectReferenceMapping employerMapping = (ObjectReferenceMapping) personDescriptor.getMappingForAttributeName("employer");
				ExpressionBuilder personE = new ExpressionBuilder();
				DatabaseField primaryKeyField = employerMapping.getReferenceDescriptor().getPrimaryKeyFields().get(0);
				DatabaseField foreignKeyField = employerMapping.getForeignKeyFields().get(0);
				Expression expression = personE.getField(primaryKeyField).equal(personE.getParameter(foreignKeyField));
				OneToOneQueryKey profitCompanyEmployer = new OneToOneQueryKey();
				profitCompanyEmployer.setName("profitCompanyEmployer");
				profitCompanyEmployer.setDescriptor(personDescriptor);
				profitCompanyEmployer.setReferenceClass(ForProfitCompany.class);
				profitCompanyEmployer.setJoinCriteria(expression);
				personDescriptor.addQueryKey(profitCompanyEmployer);
			}
			ReadAllQuery query = new ReadAllQuery(Person.class);
			query.setShouldOuterJoinSubclasses(true);
			ExpressionBuilder personE = query.getExpressionBuilder();
			// now use that query key as an ordinary field
			query.setSelectionCriteria(personE.get("profitCompanyEmployer").get("sector").like("%oil%"));
			Collection<Person> collection = (Collection<Person>) session.executeQuery(query);
			for (Person person : collection) {
				System.out.println(String.format("result: [%s, employer: [%s]]", person, person.getEmployer()));
			}
		} finally {
			entityManager.close();
		}
	}
	
	@SuppressWarnings("unchecked")
	private static void delete(EntityManagerFactory entityManagerFactory) {
		EntityManager entityManager = entityManagerFactory
				.createEntityManager();
		try {
			entityManager.getTransaction().begin();
			Query pQuery = entityManager.createQuery("SELECT p FROM Person p");
			Collection<Person> pCollection = (Collection<Person>) pQuery
					.getResultList();
			for (Person person : pCollection) {
				entityManager.remove(person);
			}
			entityManager.getTransaction().commit();
		} finally {
			if (entityManager.getTransaction().isActive()) {
				entityManager.getTransaction().rollback();
			}
			entityManager.close();
		}
	}
}