EJB 3 Developer Guide A Practical Guide for developers and architects to the Enterprise Java Beans Standard Michael Sikora BIRMINGHAM - MUMBAI EJB 3 Developer Guide Copyright © 2008 Packt Publishing All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews. Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, Packt Publishing, nor its dealers or distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book. Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information. First published: May 2008 Production Reference: 1160508 Published by Packt Publishing Ltd. 32 Lincoln Road Olton Birmingham, B27 6PA, UK. ISBN 978-1-847195-60-9 www.packtpub.com Cover Image by Michelle O'Kane ([email protected]) Credits Author Project Manager Michael Sikora Abhijeet Deobhakta Reviewers Project Coordinator Meenakshi Verma Brinell Catherine Lewis Chris Mawata Lawrence Bean Indexer Monica Ajmera Senior Acquisition Editor Douglas Paterson Proofreader Angie Butcher Development Editor Sarah Cullington Production Coordinator Shantanu Zagade Technical Editor Bhupali Khule Cover Work Shantanu Zagade Editorial Team Leader Mithil Kulkarni About the Author Michael Sikora is an enterprise architect with a background in the Unified Process and Java EE. He has a particular interest in object oriented and database technology. He has worked for many large UK clients such as ICL Fujitsu, Mercury Communications, Vodafone, and BUPA. He has used Java since 2000. Before that he spent a decade designing and developing database and data warehouse systems. He has experience in Oracle, PL/SQL, and C. In the 1980s he worked for Shell developing exploration software. He graduated in Mathematics from Essex University and has Masters degrees from London University and Imperial College. Michael currently resides in London, England and enjoys mountaineering and still hopes to complete the seven summits. His website is http://www.ejbconsultants.com. I would like to thank Arun Zachariah, Amanda Waite, George Wilk, and Paul Hudson for advice, feedback, and help on this book. From the Packt publishing staff, I would like in particular to thank Douglas Paterson for his interest in this project. I would also like to thank Sarah Cullington, Brinell Lewis, and Bhupali Khule for the smooth running of the publishing process. Finally I would like to thank the technical reviewers for some very helpful suggestions. About the Reviewers Meenakshi Verma has been part of the IT industry since 1998. She is experienced in putting up solutions across multiple industry segments using Java/J2EE technologies. She is currently based in Toronto, Canada and is working with Sapient, a leading North American Consultancy organization. Sapient is a global organization which has offices across North America, Europe and India. Meenakshi has been helping with technical reviews for books published by Packt Publishing across varied enterprise solutions. Her earlier work includes JasperReports for Java Developers, Java EE 5 Development using GlassFish Application Server, Practical Data Analysis and Reporting with BIRT. I'd like to thank my husband (Atul Verma) for his encouragement and support throughout the review of this book and many others, and my three year old son (Prieyaansh Verma) for giving me the warmth of his love despite my hectic schedules. I also owe thanks & gratitude to my Father (Mr Bhopal Singh) and Mother (Mrs Raj Bala) for laying a strong foundation in me and giving me their unconditional love and support. Chris Mawata earned his Masters degree at the University of Western Australia and his Ph.D at the University of Hawaii. He was a professor at the University of Tennessee at Chattanooga for fifteen years after which he went into Java consulting and technical training. He currently trains Java developers and writes course materials for Learning Tree International. He is also sponsored by a National Science Foundation grant to be a Java consultant for Phenotype Screening Corporation. Lawrence Bean fell out of Computer Science and into Music Education in his sophomore year of college. He graduated with a BA in Music Education from the University of Maine in 1986 and had a ten year career as a Choral Music Educator in the Kennebunk, Maine school system, while continuing his technology pursuits as a hobby. His large non-audition groups won silver at the Events America Choral Festival and his select group was featured on Good Morning America and in Yankee Magazine for their annual performances of traditional christmas carols at the highly acclaimed Kennebunkport Christmas Prelude. He fell back into Computer Science with the offer of a position as Technology Coordinator at SU#47 in greater Bath, Maine and completed his MS in Computer Science in 2006. For the past ten years he has literally built the school system's technology program, from pulling CAT-5 through the walls and constructing PCs out of spare parts to writing data analysis modules and a custom SIF-compliant Student Information System, while continuing his musical pursuits as a hobby. Throughout he has been highly involved in the Maine Music Educators Association, American Choral Directors Association of Maine, Association of Computer Technology Educators in Maine, and the Barbershop Harmony Society, holding various positions of responsibility and bringing the Maine All-State Auditions into the 21st century with on-line applications, judging, and results processing. He has been a strong advocate for free, open-source solutions for public schools and currently presents workshops on IPCop Firewalls and the Koha ILS. Larry lives with his very patient wife Betsy in Saco, Maine, USA. Table of Contents Preface 1 Chapter 1: Introduction to the EJB 3 Architecture 7 Introduction to the Java EE Architecture 7 The EJB 3 Architecture 9 EJB Container Services 11 The JPA Persistence Engine 12 EJB 3 Compared with Earlier Versions 13 Getting Started 14 Installing GlassFish 14 Testing the Installation 16 Accessing the Administrator Console 17 Shutting Down GlassFish 19 Downloading Example Source Code 19 Summary 19 Chapter 2: Session Beans 21 Introduction 21 Stateless Session Beans 22 Annotations 23 Creating a Session Bean Client 25 Running the Example 26 The Program Directory Structure 28 The Ant Build Script 29 The Application Client Container 31 Building the Application 32 Stateless Session Bean's LifeCycle 34 Stateful Session Beans 36 Stateful Session Bean's LifeCycle 39 Local Interfaces 41 Summary 44 Table of Contents Chapter 3: Entities 45 Introduction 45 EJB 3 Entities 46 Comparison with EJB 2.x Entity Beans 47 Mapping an Entity to a Database Table 48 Introducing the EntityManager 49 Packaging and Deploying Entities 53 The Program Directory Structure 53 Building the Application 54 Field-Based Annotations 56 Generating Primary Keys 57 Table Strategy 57 Sequence Strategy 58 Identity Strategy 59 Auto Strategy 59 Overriding Metadata Defaults 60 Summary 62 Chapter 4: Object/Relational Mapping 63 O/R Mapping Default Behavior 63 A Banking Example Application 64 Customer Entity 65 Account Entity 68 Address Entity 69 Referee Entity 70 Testing the Application 71 O/R Mapping Overriding Defaults 74 Customer Entity 75 Account Entity 79 Address Entity 80 BankServiceBean 82 O/R Mapping Additional Annotations 84 Referee Class 88 BankServiceBean 88 Composite Primary Keys 89 O/R Inheritance Mapping 91 SINGLE_TABLE Strategy 92 JOINED Strategy 94 Table per Concrete Class Strategy 95 Summary 96 [ ii ] Table of Contents Chapter 5: The Java Persistence Query Language 97 Introduction 97 Simple Queries 98 Projection 99 Conditional Expressions 99 Aggregate Functions 101 GROUP BY 102 HAVING 102 Queries with Relationships 103 Joins 103 Inner Joins 103 Outer Joins 104 Fetch Joins 104 Collection Comparison Expressions 105 Constructor Expressions 105 SubQueries 106 Functions 107 CONCAT 107 SUBSTRING 107 TRIM 107 LOWER and UPPER 107 LENGTH 108 LOCATE 108 ABS 108 SQRT 108 MOD 108 SIZE 109 Queries with Parameters 109 Positional Parameters 109 Named Parameters 110 Named Queries 110 Handling Date and Time 112 @Temporal annotation 112 Queries with Date Parameters 113 Datetime Functions 113 Bulk Update and Delete 114 Native SQL 114 Summary 118 [ iii ]