EJB cookbook

353 Pages·2003·2.802 MB·English

by  Ben G Sullins, Mark B Whipple

EJB Cookbook

EJB Cookbook
BENJAMIN G. SULLINS
MARK B. WHIPPLE
MANNING
Greenwich
(74° w. long.)
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Printed in the United States of America
1 2 3 4 5 6 7 8 9 10 – VHG – 06 05 04 03
To Jenny, Elijah, and Samuel
—Ben
To my wonderful wife, Margie,
and my son, Alexander
—Mark

contents

preface xv
acknowledgments xvii
about this book xviii
author online xxii
about the cover illustration xxiii
PART I APPETIZERS ....................................................... 1
1 Client code 3
1.1 Invoking a local EJB from another EJB 4
1.2 Invoking a remote EJB from another EJB 6
1.3 Accessing EJBs from a servlet 8
1.4 Invoking an EJB from a JavaServer Page 12
1.5 Invoking EJB business logic from a JMS system 15
1.6 Persisting a reference to an EJB instance 18
1.7 Retrieving and using a persisted EJB reference 20
1.8 Persisting a home object reference 21
1.9 Comparing two EJB references for equality 23
vii
viii CONTENTS
1.10 Using reflection with an EJB 25
1.11 Invoking an EJB from an applet 27
1.12 Improving your client-side EJB lookup code 31
2 Code generation with XDoclet 33
An XDoclet appetizer 35
2.1 Generating home, remote, local, and local
home interfaces 37
2.2 Adding and customizing the JNDI name for the
home interface 43
2.3 Keeping your EJB deployment descriptor current 45
2.4 Creating value objects for your entity beans 47
2.5 Generating a primary key class 53
2.6 Avoiding hardcoded XDoclet tag values 56
2.7 Facilitating bean lookup with a utility object 58
2.8 Generating vendor-specific deployment descriptors 62
2.9 Specifying security roles in the bean source 63
2.10 Generating and maintaining method permissions 64
2.11 Generating finder methods for entity
home interfaces 66
2.12 Generating the ejbSelect method XML 67
2.13 Adding a home method to generated
home interfaces 68
2.14 Adding entity relation XML to the
deployment descriptor 70
2.15 Adding the destination type to a message-driven
bean deployment descriptor 71
2.16 Adding message selectors to a message-driven bean
deployment descriptor 73
CONTENTS ix
PART II MAIN COURSES................................................ 75
3 Working with data 77
3.1 Using a data source 78
3.2 Creating EJB 2.0 container-managed persistence 81
3.3 Using different data sources for different users 85
3.4 Using a database sequence to generate primary key
values for entity beans 88
3.5 Using a compound primary key for your entity beans 92
3.6 Retrieving multiple entity beans in a single step 95
3.7 Modeling one-to-one entity data relationships 97
3.8 Creating a one-to-many relationship for entity beans 101
3.9 Using entity relationships to create a
cascading delete 104
3.10 Developing noncreatable, read-only entity beans 107
3.11 Invoking a stored procedure from an EJB 109
3.12 Using EJB-QL to create custom finder methods 111
3.13 Persisting entity data into a database view 115
3.14 Sending notifications upon entity data changes 117
3.15 Creating an interface to your entity data 120
3.16 Retrieving information about entity data sets 122
3.17 Decreasing the number of calls to an entity bean 124
3.18 Paging through large result sets 126
4 EJB activities 133
4.1 Retrieving an environment variable 134
4.2 Implementing toString() functionality for an EJB 136
4.3 Providing common methods for all your EJBs 137