JPA tips 2

A previous post about this topic: http://hilaltarakci.blogspot.com/2011/03/jpa-tips.html

Actually, long version of this post includes notes taken while i was reading Chapter 9- Working with Objects of book Java Persistence with Hibernate (http://www.manning.com/bauer2/). However, i could not post it because of the copyright rules..

 But at least, i can recommend to buy the book and read the whole chapter..

hibernate on glassfish

A way of  powering glassfish with hibernate support (instead of toplink) is directly copying hibernate runtime.jar files under glassfish's domain1/lib folder. However, this forces all deployed applications to use the same hibernate version. Therefore, the best solution is packaging hibernate .jars with the application itself.

Here is a useful link which explains how to use hibernate JPA on glassfish: http://javafromthetrenches.wordpress.com/2011/01/15/using-hibernate-jpa-with-glassfish/

The following dependencies worked for me:

<dependency org="antlr"
name="antlr"
rev="2.7.6"/>

<dependency org="asm"
name="asm"
rev="1.5.3"/>

<dependency org="asm"
name="asm-attrs"
rev="1.5.3"/>

<dependency org="cglib"
name="cglib"
rev="2.2"/>

<dependency org="commons-collections"
name="commons-collections"
rev="2.1.1"/>

<dependency org="commons-logging"
name="commons-logging"
rev="1.1"/>

<dependency org="dom4j"
name="dom4j"
rev="1.6.1"/>

<dependency org="ehcache"
name="ehcache"
rev="1.2.3"/>

<dependency org="javax.transaction"
name="jta"
rev="1.1"/>

<dependency org="org.hibernate"
name="hibernate-tools"
rev="3.2.0.ga"/>

<dependency org="org.hibernate"
name="hibernate-annotations"
rev="3.3.1.GA"/>

<dependency org="org.hibernate"
name="hibernate-commons-annotations"
rev="3.3.0.ga"/>

<dependency org="org.hibernate"
name="hibernate-entitymanager"
rev="3.3.2.GA"/>

<dependency org="javassist"
name="javassist"
rev="3.4.GA"/>

<dependency org="org.hibernate"
name="ejb3-persistence"
rev="3.3.2.Beta1"/>

<-- if hibernate cloning api beanlib is going to be used -->
<dependency org="net.sf.beanlib"
name="beanlib"
rev="5.0.2beta"/>

<-- if hibernate cloning api beanlib is going to be used -->
<dependency org="net.sf.beanlib"
name="beanlib-hibernate"
rev="5.0.2beta"/>

<!-- if postgresql driver is going to be used -->
<dependency org="it.cnr.isti.domoware"
name="org.postgresql.jdbc4"
rev="8.3-603"/>


The listed dependencies are not latest version of hibernate, however it is a working hibernate runtime set of jars. Here is an ongoing discussion about the topic: http://www.java.net/forum/topic/glassfish/glassfish/updating-support-hibernate-glassfish-need-communitys-help

changing hibernate log level

In this link, hibernate log level is changed programmatically:

http://stackoverflow.com/questions/847041/how-do-i-change-hibernate-logging-level

I adopted this way..

Logger.getLogger("org.hibernate").setLevel(Level.ERROR);

However, as the link says, this solution makes you dependent on the logger implementation.

notes on schuchert jpa tutor 4

finally the last tutor at http://schuchert.wikispaces.com/JPA+Tutorial+4+-+Inheritance+and+Polymorphic+Queries

lets move!

• remember to rename BookAlreadyCheckedOut as ResourceAlreadyCheckedOut and BookNotCheckedOut as ResourceNotCheckedOut to get rid of compilation errors.
• the same issue as in http://hilaltarakci.blogspot.com/2009/10/notes-on-schuchert-jpa-tutor-3.html

now, all tests should pass..

well, time to go to my own project, thanks to schuchert, tutors are really helpful :)

notes on schuchert jpa tutor 3

now the tutor i follow is http://schuchert.wikispaces.com/JPA+Tutorial+3+-+A+Mini+Application

lets see what happens..

so perfect, just in test methods of LibraryTest, the assertEquals methods used to compare floats that take 2 params are deprecated. Instead define a delta as follows and pass it as 3rd param to mentioned methods. Thus, tests will pass i think :)

private static final float DELTA = (float) 0.0;


...

assertEquals(.., .., DELTA);

notes on schuchert jpa tutor 2

the tutor is at http://schuchert.wikispaces.com/JPA+Tutorial+2+-+Working+with+Queries+1

lets follow..

• comment out the exception in the  unsuccessfulSingleResultTooManyEntries  test case of QueriesTest.. thus, it will pass..

 @Test// (expected = NonUniqueResultException.class)

    public void unsuccessfulSingleResultTooManyEntries() {

insertPerson();

        insertPerson();




        // This will fail because we expect a single result

        // but in fact there are 2 results returned.

        em.createQuery("from Person").getSingleResult();

    }

this is because,  getSingleResult() does not get angry when there are more than one records and just picks the first one..

notes on schuchert jpa tutor 1

i am following schuchert's jpa tutor 1 at http://schuchert.wikispaces.com/JPA+Tutorial+1+-+Getting+Started

however, my environment is netbeans 6.5 + glassfish v2 + postgre..

lets note down some drawbacks i faced:

• i get the following error while trying to run PersonTest :
  

Testcase: emptyTest(entity.PersonTest):        Caused an ERROR

[PersistenceUnit: SchuchertJpaTutor1PU] Unable to build EntityManagerFactory

javax.persistence.PersistenceException: [PersistenceUnit: SchuchertJpaTutor1PU] Unable to build EntityManagerFactory

        at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:677)

        at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:126)

        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:51)

        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:33)

        at entity.PersonTest.initEmfAndEm(PersonTest.java:24)

Caused by: org.hibernate.HibernateException: Could not find datasource

        at org.hibernate.connection.DatasourceConnectionProvider.configure(DatasourceConnectionProvider.java:56)

        at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:124)

        at org.hibernate.ejb.InjectionSettingsFactory.createConnectionProvider(InjectionSettingsFactory.java:29)

        at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:62)

        at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2009)

        at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1292)

        at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)

        at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:669)

Caused by: javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file:  java.naming.factory.initial

        at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:645)

        at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)

        at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:325)

        at javax.naming.InitialContext.lookup(InitialContext.java:392)

        at org.hibernate.connection.DatasourceConnectionProvider.configure(DatasourceConnectionProvider.java:52)

Testcase: emptyTest(entity.PersonTest):        Caused an ERROR

null

java.lang.NullPointerException at entity.PersonTest.cleanup(PersonTest.java:31)

Test entity.PersonTest FAILED

to fix:

- use in memory database in unit tests with persistence.xml as follows:

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">

<persistence-unit name="SchuchertJpaTutor1TestPU" transaction-type="RESOURCE_LOCAL">

    <provider>org.hibernate.ejb.HibernatePersistence</provider>

    <non-jta-data-source></non-jta-data-source>

    <exclude-unlisted-classes>false</exclude-unlisted-classes>

    <properties>

        <property name="hibernate.connection.url" value="jdbc:hsqldb:mem:unit-testing-jpa"/>

        <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>

        <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>

        <property name="hibernate.hbm2ddl.auto" value="create-drop"/>

        <property name="hibernate.connection.username" value="sa"/>

        <property name="hibernate.connection.password" value=""/>

    </properties>

  </persistence-unit>

</persistence>

- add hsqldb.jar and (possibly) servlet.jar to test libs 

and run the test again, it should pass now..

(more on http://eskatos.wordpress.com/2007/10/15/unit-test-jpa-entities-with-in-memory-database/)

• when Address is added to Person, delete the final keyword from getter and setter methods for address.(it results in compile error..)

the project is here: http://schuchert.wikispaces.com/JPA+Tutorial+1+-+Entire+Source+Base

i will continue with the next tutorial, so see you at the next blog entry :)

jpa tutorial

the tutor to be followed: http://schuchert.wikispaces.com/JPA+Tutorial+1+-+Getting+Started

linked from http://schuchert.wikispaces.com/EJB+3+and+Java+Persistence+API

TODO: details soon..

Edit on 04/10/2009 at 14:10: http://hilaltarakci.blogspot.com/2009/10/notes-on-schuchert-jpa-tutor-1.html

Edit on 05/10/2009 at 17:30:http://hilaltarakci.blogspot.com/2009/10/notes-on-schuchert-jpa-tutor-2.html

Edit on 06/10/2009 at 10:53: http://hilaltarakci.blogspot.com/2009/10/notes-on-schuchert-jpa-tutor-3.html

Edit on 06/10/2009 at 14:32: http://hilaltarakci.blogspot.com/2009/10/notes-on-schuchert-jpa-tutor-4.html

jpa annotation reference documentation

for jpa annotations 

• http://www.oracle.com/technology/products/ias/toplink/jpa/resources/toplink-jpa-annotations.html   --> very famous reference
• http://www.jpox.org/docs/1_2/jpa/annotations.html
  

for hibernate annotations

• http://docs.jboss.org/hibernate/stable/annotations/reference/en/html_single/ ,  same documentation at a different address  http://docs.huihoo.com/hibernate/annotations-reference-3.2.1/
  
• http://tadtech.blogspot.com/2007/09/hibernate-association-mappings-in.html --> only the associations
  
• http://www.roseindia.net/hibernate/ --> with code samples :)

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role- no session or session was closed

the exception is:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.example.ws.Library.bookList, no session or session was closed


unfortunately,

Hibernate does not support lazy initialization for detached objects.

http://docs.jboss.org/hibernate/stable/core/reference/en/html_single/#performance-fetching-lazy

so, one possible solution is to clone the entity if it will be used out of session..

a simple example web service project:

Book.java

package com.example.ws;

import java.io.Serializable;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

@Entity

public class Book implements Serializable {

private static final long serialVersionUID = 1L;

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

private Long id;

private String title;

public Long getId() {

return id;

}

public void setId(Long id) {

this.id = id;

}

public String getTitle() {

return title;

}

public void setTitle(String title) {

this.title = title;

}

@Override

public int hashCode() {

int hash = 0;

hash += (id != null ? id.hashCode() : 0);

return hash;

}

@Override

public boolean equals(Object object) {

// TODO: Warning - this method won't work in the case the id fields are not set

if (!(object instanceof Book)) {

return false;

}

Book other = (Book) object;

if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {

return false;

}

return true;

}

@Override

public String toString() {

return "com.example.ws.Book[id=" + id + "]";

}

}

Library.java

package com.example.ws;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.List;

import javax.persistence.CascadeType;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.OneToMany;

@Entity

public class Library implements Serializable {

private static final long serialVersionUID = 1L;

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

private Long id;

private String name;

@OneToMany(fetch = FetchType.LAZY, cascade= CascadeType.ALL)

private List bookList = new ArrayList();

public Long getId() {

return id;

}

public void setId(Long id) {

this.id = id;

}

public List getBookList() {

return bookList;

}

public void setBookList(List bookList) {

this.bookList = bookList;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

@Override

public int hashCode() {

int hash = 0;

hash += (id != null ? id.hashCode() : 0);

return hash;

}

@Override

public boolean equals(Object object) {

// TODO: Warning - this method won't work in the case the id fields are not set

if (!(object instanceof Library)) {

return false;

}

Library other = (Library) object;

if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {

return false;

}

return true;

}

@Override

public String toString() {

return "com.example.ws.Library[id=" + id + "]";

}

}

HibernateUtil.java

package util;

import com.example.ws.Book;

import com.example.ws.Library;

import java.util.ArrayList;

import java.util.List;

import javax.persistence.EntityManager;

import javax.persistence.EntityManagerFactory;

import javax.persistence.Persistence;

import javax.persistence.PersistenceUnit;

import javax.persistence.Query;

/**

*

* @author hilal.tarakci

*/

public class HibernateUtil {

@PersistenceUnit(unitName = "HibernateLazyInitFixPU")

private EntityManagerFactory emf = null;

public EntityManager getEntityManager() {

if (emf == null) {

emf = Persistence.createEntityManagerFactory("HibernateLazyInitFixPU");

}

return emf.createEntityManager();

}

public void create(Library item) throws Exception {

EntityManager em = null;

try {

em = getEntityManager();

em.getTransaction().begin();

em.persist(item);

em.getTransaction().commit();

} catch (Exception ex) {

try {

if (em != null) {

em.getTransaction().rollback();

}

} catch (Exception re) {

re.printStackTrace();

}

throw ex;

} finally {

if (em != null) {

em.close();

}

}

}

public List retrieveRecordsOfBook() {

EntityManager em = getEntityManager();

try {

Query q = em.createQuery("select object(o) from Book as o");

List bookList = new ArrayList();

List tempBookList = q.getResultList();

for (Book tempBook : tempBookList) {

Book book = new Book();

book.setId(tempBook.getId());

book.setTitle(tempBook.getTitle());

bookList.add(book);

}

return bookList;

} finally {

em.close();

}

}

public List retrieveRecordsOfLibrary() {

EntityManager em = getEntityManager();

try {

Query q = em.createQuery("select object(o) from Library as o");

List libList = new ArrayList();

List tempLibList = q.getResultList();

for (Library tempLib : tempLibList) {

Library lib = new Library();

lib.setId(tempLib.getId());

lib.setName(tempLib.getName());

List bookList = new ArrayList();

for(Book tempBook: tempLib.getBookList()) {

Book book = new Book();

book.setId(tempBook.getId());

book.setTitle(tempBook.getTitle());

bookList.add(book);

}

lib.setBookList(bookList);

libList.add(lib);

}

return libList;

} finally {

em.close();

}

}

}

HibernateLazyInit.java

package com.example.ws.service;

import com.example.ws.Book;

import com.example.ws.Library;

import java.util.List;

import javax.jws.Oneway;

import javax.jws.WebMethod;

import javax.jws.WebService;

import util.HibernateUtil;

@WebService()

public class HibernateLazyInit {

private HibernateUtil util = new HibernateUtil();

@WebMethod(operationName = "insertRecords")

@Oneway

public void insertRecords() {

try {

Book book1 = new Book();

book1.setTitle("A Good Story");

Book book2 = new Book();

book2.setTitle("A Bad Story");

Library library1 = new Library();

library1.setName("An Excellent Library");

library1.getBookList().add(book1);

library1.getBookList().add(book2);

util.create(library1);

} catch (Exception ex) {

ex.printStackTrace();

}

}

@WebMethod(operationName = "retrieveRecordsOfBook")

public List retrieveRecordsOfBook() {

return util.retrieveRecordsOfBook();

}

@WebMethod(operationName = "retrieveRecordsOfLibrary")

public List retrieveRecordsOfLibrary() {

return util.retrieveRecordsOfLibrary();

}

}

.. and the client call

public class Main {

void insertRecords() {

try { // Call Web Service Operation

com.example.ws.service.HibernateLazyInitService service = new com.example.ws.service.HibernateLazyInitService();

com.example.ws.service.HibernateLazyInit port = service.getHibernateLazyInitPort();

port.insertRecords();

} catch (Exception ex) {

// TODO handle custom exceptions here

ex.printStackTrace();

}

}

int retrieveRecordsOfBook() {

try { // Call Web Service Operation

com.example.ws.service.HibernateLazyInitService service = new com.example.ws.service.HibernateLazyInitService();

com.example.ws.service.HibernateLazyInit port = service.getHibernateLazyInitPort();

// TODO process result here

java.util.List result = port.retrieveRecordsOfBook();

System.out.println("Result = "+result);

return result.size();

} catch (Exception ex) {

// TODO handle custom exceptions here

ex.printStackTrace();

return 0;

}

}

int retrieveRecordsOfLibrary() {

try { // Call Web Service Operation

com.example.ws.service.HibernateLazyInitService service = new com.example.ws.service.HibernateLazyInitService();

com.example.ws.service.HibernateLazyInit port = service.getHibernateLazyInitPort();

// TODO process result here

java.util.List result = port.retrieveRecordsOfLibrary();

System.out.println("Result = "+result);

return result.size();

} catch (Exception ex) {

// TODO handle custom exceptions here

ex.printStackTrace();

return 0;

}

}

public static void main(String[] args) {

// TODO code application logic here

Main client = new Main();

client.insertRecords();

System.out.println("Size of books : " + client.retrieveRecordsOfBook() );

System.out.println("Size of library : " + client.retrieveRecordsOfLibrary() );

}

btw, the ide is netbeans 6.5.1 with glassfish.

Edit on 11:14 :

the above solution is good when you want to use standard jpa and stay away from hibernate specific solutions..

but if it is ok to use hibernate specific annotations, you can try @Fetch(FetchType.JOIN)..

http://docs.jboss.org/hibernate/stable/annotations/reference/en/html_single/#entity-hibspec-singleassoc-fetching

Edit on 14/12/2010 :

HibernateBeanReplicator is also a solution.. see http://hilaltarakci.blogspot.com/2009/09/java-deep-clone-library.html for details..

hibernate association mappings

excellent documentation :)

http://tadtech.blogspot.com/2007/09/hibernate-association-mappings-in.html