Quickstart Apache Axis2: A practical guide to creating quality web services

180 Pages·2008·2.38 MB·English

by  Deepal Jayasinghe

Quickstart Apache Axis2
A practical guide to creating quality web services
Deepal Jayasinghe

BIRMINGHAM - MUMBAI
Quickstart Apache Axis2
Copyright © 2008 Packt Publishing
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First published: May 2008
Production Reference: 1160508
Published by Packt Publishing Ltd.
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Olton
Birmingham, B27 6PA, UK.
ISBN 978-1-847192-86-8
www.packtpub.com
Cover Image by Vinayak Chittar ([email protected])
Credits
Author Project Coordinator
Deepal Jayasinghe Patricia Weir
Reviewers Indexer
Ramanujam A. Rao Monica Ajmera
Senior Acquisition Editor Proofreader
Rashmi Phadnis Chris Smith
Technical Editor Production Coordinator
Shilpa Dube Aparna Bhagat
Editorial Team Leader Cover Work
Mithil Kulkarni Aparna Bhagat
Project Manager
Abhijeet Deobhakta
About the Author
Deepal Jayasinghe is a Technical Lead at WSO2 Inc., an open-source software
development company that creates middleware platforms for Web Services. He
joined WSO2, Inc. in August, 2005. He has more than 3 years of experience with
SOA and Web Services in addition to being a contributing member of the Apache
Axis2 project since its inception. He is a key architect and a developer of the Apache
Axis2 Web Service project and has led a number of releases. In addition to Axis2,
he has made major contributions to Apache Synapse, Apache Axiom, and Apache
XMLSchema projects. Deepal has written more than 30 technical magazine articles,
research papers, and has delivered speeches in various SOA and Web Services
conferences. He is an Apache Web Services PMC member, an Apache committer,
and an Apache Member. His expertise lies mainly in distributed computing,
fault-tolerant systems, and Web Services-related technologies. He has a B.Sc. in
Engineering from the University of Moratuwa, Sri Lanka and and will be starting
graduate studies at Georgia Institute of Technology in fall, 2008.
Contact: [email protected].
First of all, I want to thank the Apache Axis2 developers and Axis2
community who have contributed towards making this Web Services
framework a world-renowned success in a relatively short period of
time. Thank you!

I would like to thank Dr Sanjiva Weerawarana, Founder, Chairman
and CEO of WSO2, Inc., without whose support, vision, guidance,
and belief in my work this effort would never have been realized.
I owe countless thanks to my parents and dear wife for always
being there and supporting me in so many ways. This book would
not have been possible without everything that they have done
for me. Special thanks to my colleagues Suran Jayathilaka, Devaka
Randeniya, and Charitha Kankanamage for reviewing my writings,
validating the samples, providing insight, and contributing to this
effort in many other ways. Special thanks to Srinath Hemapani,
Ajith Ranabahu, Eran Chinthaka, Davanam Sirinivas, Glen Daniels,
Paul Fremantle, Chathura Herath, Jaliya Ekanayake, and all
other key members of the Axis2 team without whose tremendous
contributions and wisdom Axis2 would not have been possible.
For the creation of this work, I am blessed with a strong team of
technical reviewers, superior editorial and production professionals
from Packt Publishing. My sincere thanks to all of you for your
tireless efforts.
About the Reviewer
Ramanujam A. Rao is a software architect and an engineer with over 12 years
of experience in designing and developing large-scale enterprise applications. He
is currently involved in consulting in the area of enterprise-application architecture
and helps to build scalable and distributed applications. He also has expertise in
building enterprise-technology standards and cultivating architecture capabilities.
He lives in Columbus, OH, USA with his wife and two-year old daughter.
Contact: [email protected].
Table of Contents
Preface 1
Chapter 1: Introduction 7
Web Service History 7
Web Services Overview 8
How Do Organizations Move into Web Services? 9
Web Services Model 10
Web Services Standards 10
XML-RPC 11
SOAP 12
Web Services Addressing (WS-Addressing) 12
Service Description 13
Web Services Description Language (WSDL) 13
Web Services Life Cycle 14
Apache Web Service Stack 14
Why Axis2? 15
Download and Install Axis2 16
Binary Distribution 16
WAR Distribution 17
Source Distribution 18
JAR Distribution 18
Summary 18
Chapter 2: Looking into Axis2 19
Axis2 Architecture 19
Core Modules 20
XML Processing Model 21
SOAP Processing Model 21
Information Model 23
Deployment Model 24
Client API 25
Transports 26
Other Modules 27
Code Generation 27
Data Binding 27
Extensible Nature of Axis2 28
Service Extension of the Module 28
Table of Contents
Custom Deployers 29
Message Receivers 29
Summary 29
Chapter 3: AXIOM 31
Overview and Features 31
What is Pull Parsing? 32
AXIOM—Architecture 32
Working with AXIOM 33
Creating an AXIOM 33
Creating an AXIOM from an Input Stream 34
Creating an AXIOM Using a String 35
Creating an AXIOM Programmatically 35
Adding a Child Node and Attributes 36
Working with OM Namespaces 37
Working with Attributes 37
Traversing the AXIOM Tree 38
Serialization 38
Advanced Operations with AXIOM 40
Using OMNavigator for Traversing 40
Xpath Navigation 41
Accessing the Pull-Parser 41
AXIOM and SOAP 42
Summary 43
Chapter 4: Execution Chain 45
Handler 45
Writing a Simple Handler 46
Phase 48
Types of Phases 49
Global Phase 49
Operation Phase 51
Phase Rules 51
Phase Name 52
phaseFirst 52
phaseLast 52
before 52
after 53
after and before 53
Invalid Phase Rules 53
Flow 54
Module Engagement and Dynamic Execution Chain 55
[ ii ]
Table of Contents
Special Handlers in the Chain 56
TransportReceiver 56
Dispatchers 56
MessageReceiver 57
TransportSender 58
Summary 58
Chapter 5: Hacking Deployment 59
What's New in Axis2 Deployment? 59
J2EE-like Deployment Mechanism 60
Hot Deployment and Hot Update 61
Repository 62
Change in the Way of Deploying Handlers (Modules) 62
New Deployment Descriptors 63
Global Descriptor (axis2.xml) 64
Service Descriptor (services.xml) 64
Module Descriptor (module.xml) 65
Available Deployment Options 65
Archive-Based Deployment 66
Directory-Based Deployment 66
Deploying a Service Programmatically 66
POJO Deployment 67
Deploying and Running a Service in One Line 69
Summary 69
Chapter 6: Information Model 71
Introduction 71
Axis2 Static Data 71
AxisConfiguration 73
Parameters 75
MessageFormatters and MessageBuilders 76
TransportReceiver and TransportSender 76
Flows and PhaseOrder 76
AxisModule 77
Service Description Hierarchy 77
AxisServiceGroup 78
AxisService 78
AxisOperation 78
AxisMessage 79
Axis2 Contexts 79
ConfigurationContext 80
ServiceGroupContext 81
ServiceContext 81
[ iii ]