1. Introducing Axis2 Ajith Ranabahu
Lanka Software Foundation and Apache Software Foundation

2. The Axis2 Team (in alphabetical order)
Committers
Contributors
Ajith Ranabahu
Aleksander Slominski
Ashutosh Shahi
Chathura Herath
Dasarath Weeratunga
Deepal Jayasinghe
Davanum Srinivas
Eran Chinthaka
Glen Daniels
Jaliya Ekanayake
Jeyachandra Rao
Sanjiva Weerawarana
Srinath Perera
Thilina Gunaratne
Venkat Reddy
Anne Thomas Manes
Chamil Thanthirimudalige
Chengshin Lee
Geoffrey Fox
Gulliame Sauthier
Paul Freemantle
Shawn Dahlen
Steve Loughran
Tom Jordahl
Arrange the names in alphabetical order
And a lot more

3. Agenda Introduction and Motivation The “big picture”
Key Features of Axis2
High Performance XML Processing Model
Extensible Messaging Engine
Pluggable Module Architecture
Improved Deployment Model
New Client API
Optional Pluggable Data Binding
REST Support
Other Improvements
Summary

4. Introduction – What is SOAP ?
An XML envelope to carry application messages
<s:Envelope>
<s:Body>
Your XML Goes Here
</s:Body>
</s:Envelope>
Highly extensible to layer QoS (security, reliability, etc.)
<s:Header>
Extension data
</s:Header>
Defined abstractly – supports any serialization

5. Introduction – What are Web Services ?
Services based on SOAP over HTTP
Governed by WSDL, UDDI and other WS-* specifications
A linking mechanism for heterogeneous systems

6. Introduction – SOAP Stacks
Initial model – SOAP carries RPC requests & responses in XML form
Apache SOAP
Allow access to headers for extensibility
Apache Axis
Modular platform to support Web services architecture
Apache Axis2

7. A Quick Look At SOAP Stacks First Generation :: Apache SOAP
First Apache driven SOAP stack
Apache SOAP
Based on DOM
Slower and memory intensive

8. A Quick Look … Second Generation :: AXIS
Based on SAX
Introduced the handler architecture for SOAP stacks
Faster and better than Apache SOAP
Wide Industry Acceptance
Integrated to major application servers like WebSphere and JBoss
Highly Interoperable

9. Motivation for Axis2 Limitations of handler architecture
Inherent request/response nature
Need for more document centric interactions
Need for more asynchrony
Need to support new specifications like WSDL 2.0 and various QoS protocols

10. Axis2 Architecture - The “big picture”
The Component View
StAX
AXIOM
Module
Framework
(Modules, Handlers and Phases)
Engine
Registry
Transport and Data binding
Core

11. Axis2 “big picture” (Cont..)
The “Dynamic” View
Application
Transport
Phase Z
Phase Y
Phase X
XML
Message
Engine
Receiver
AXIOM representation

12. Key Features of Axis2 New XML Infoset Representation
Deferred building
StAX integrated
Extensible Messaging Engine
Pluggable Module Architecture
Improved Deployment Model
New Client API
Optional Pluggable Data Binding
REST Support

13. New XML Infoset Representation

14. New XML Infoset Representation
Known as AXIOM (Axis Object Model)
Yet another XML object model
API is more like a simplified DOM
Fundamental Difference ?
Objects are made “on demand” using a pull model
Allows direct access to the underlying pull stream with or without building the tree
Support for storing binary values

15. New XML Infoset Representation (Cont…)
API also provides a StAX parser interface at any element
Allows the event based navigation of the OM tree.

16. New XML Infoset Representation (Cont…)
AXIOM
Pull Event Stream
Push Event Stream
Programmatical Creation

17. New XML Infoset Representation (cont..)
In built binary storage support
Can store binary (unchanged)
Natively supports XOP/MTOM
XOP? MTOM??
XOP - XML Optimized Packaging
MTOM - Message Transfer Optimization Mechanism
A way to send binary content without base64 encoding
Put some XOP explanation here

18. Use of AXIOM in Axis2
AXIOM is the primary means of representing/manipulating the XML message inside Axis

19. Extensible Messaging Engine

20. Extensible Messaging Engine
It is the “core”
A pure SOAP processor
Not aware of any java web service specifications (e.g. JAX-RPC)
Contains
A Context Hierarchy
Concept of descriptors and contexts
Phases
Phases ?
Have to add a context herarchy picture here

21. The Messaging Engine - Phases
Concept of Phases
A phase is a particular stage in execution.
E.g. pre-dispatch, Transport
Each Phase contains a group of Handlers
Handlers are linked to rules that say where the handler should be placed
A phase represents a particular stage of execution

22. The Messaging Engine - Phases (Cont…)
Standard Phases
Transport phase
Pre-dispatch phase
Dispatch phase
Post-dispatch phase
Policy determination phase

23. The Messaging Engine - Pipe view
Can be viewed as a pipe

24. The Messaging Engine - Message Exchange Patterns
Describes the exchange pattern of SOAP messages per given operation.
E.g.
In – Out
In Only
In – In – Out !
WSDL 2.0 defines 8 standard MEPs.

25. The Messaging Engine - Message Exchange Patterns (cont..)
Axis2 supports MEPs with the piped model of the engine
Can be easily extended to support custom MEPs

26. The Messaging Engine – Contexts and Descriptors
Places to keep static and dynamic run time information
Descriptors
Keeps static information
E.g. deployment descriptor parameters
Contexts
Keeps dynamic information

27. The Messaging Engine – Contexts and Descriptors
Configuration Context
Service Context
Operation Context
Message Context
Axis Configuration
Service Description
Operation Description
Message Description

28. Pluggable Module Architecture

29. Pluggable Modules Extensions for the server
Meant to provide a specific functionality
E.g. Security,Reliability etc
Consists of
Handlers
Special Module class
A Descriptor (module.xml)

30. Pluggable Modules (Cont..)
Archived to make a single bundle
Known as a “.mar” file
Concept of Engaging
Engaging a module means activating it
Can be done
Per System
Per Service
Per Operation

31. The Messaging Engine – Detailed Components View
Registry
Modules
Engine
Contexts

32. Pluggable Modules - Example
The WS-Addressing module
Contains
Addressing-in handler
Placed in the pre-dispatch phase – in pipe
Addressing out handler
Placed in the message-out – out pipe

33. Improved Deployment Model

34. Improved Deployment Model
Faster and Easier Deployment
Service Archive files (.aar files)
A collection of resources needed for a service
Includes
Service implementation
Handlers (optional)
Service descriptor (service.xml)

35. Improved Deployment Model (Cont…)
Hot Deployment
“Drop in” deployment
Uploaded through
File system
Axis2 web application

36. New Client API

37. New Client API Supports an Asynchronous programming style
Concept of callbacks for the client
Can handle both transport dependent and transport independent asynchrony.
Based on the “MEP Client”
Can be extended to support custom MEPs

38. Pluggable Data Binding

39. Pluggable Data Binding
How to provide data binding support ?
Use a well established framework
Avoid reinventing the wheel!
Flexible
Adds more functionality
E.g. XMLBeans supports the complete XML Schema
Features an API that can bind to another data binding framework

40. Pluggable Data Binding (Cont …)
Currently supported frameworks
XMLBeans
We also plan to Axis data binding framework by default.
Sufficient for simple data binding needs

41. REST Support

42. REST Support in Axis Axis2 has built in support for REST
A system wide switch to enable REST
Selection of messages depending on SOAPAction / Content type
All REST messages will be treated similarly to SOAP messages inside the system

43. Other Improvements Support for transports other than HTTP
Extensive tool support
Other JVM languages
Groovy

44. Improvements Tools Complex operations need user friendly tools
Service and module archive generator tools
Axis Administration web application
Improved WSDL2Code tool
IDE plug-ins

45. Improvements (cont ..) Other transports
SMTP / POP based transport
TCP based transport
JMS based transport
Can easily switch between different transports

46. Improvements (Cont…) Support for other languages
Ability to write implementations in various JVM languages
Groovy
Client stub generation for languages other than Java
IKVM based C# and VB.Net code ! (experimental)

47. Summary Introduction and Motivation Key Features of Axis2
High Performance XML Processing Model
Extensible Messaging Engine
Pluggable Module Architecture
Improved Deployment Model
New Client API
Optional Pluggable Data Binding
REST Support
Summary with points

48. You Can Help! Join axis-dev (filter on “[axis2]”)
Weekly IRC chats on Wednesday or Thursday.
Submit ideas, code
Become a committer

49. Questions ?

50. Thank you