Axis2 Landscape

Axis2 Landscape
EranChinthaka
School of Informatics and Computing
Indiana University

Agenda
Pre-Axis2 Era
Axis2 – Diving in to Architecture
How all projects fit together
Q&A

About Me
Member, PMC Member and committer in Apache Software Foundation
PhD student in Indiana University, Bloomington, Indiana
Research on using usage patterns and knowledge-based techniques to improve job executions in large-scale systems (grids, clouds, etc)

Apache WS Timeline
Apache SOAP
Developed by IBM research team
Donated by IBM shortly after IBM joined the SOAP/WS initiative
Proof of concept
Apache Axis1
SAX based
Handler architecture
Widely used in many products
WSS4J, Sandesha, Kandula, Pubscribe, WSRF support

Why Axis2
Changes to Web service landscape mandated an extensible architecture
WS-Addressing , Reliable Messaging, WS-MEX
Performance
Parsers, message processing
Programming Abstractions
Asynchronous invocations, Message Exchange Patterns
Ease of use
Better APIs, Hot Deployment and other capabilities

Axis2 Features
High performance XML processing model
Extensible Messaging Engine
Rich Information Model
Pluggable module, data binding, transports architecture
Can support XMLBeans, ADB, JAXB, JiBX, etc.,
Ability to plug-in any WS-* implementation
Easy to use deployment model
Convenient programming abstractions
WSDL 1.1, 2.0 and SOAP 1.1, 1.2 support
WSDL 2.0 HTTP binding, mimicing REST style invocations
Cloud computing support
Auto-scaling on Amazon
Clustering support

Axis2 Landscape
Community
Academic Usage
De-facto web services engine in research projects
Eucalyptus[1]
Industry Usage
Companies started consulting on Axis2 and/or building products on Axis2
De-facto Web service engine for all the interoperability efforts
[1]The Eucalyptus Open-source Cloud-computing System, Daniel Nurmi, Rich Wolski, Chris Grzegorczyk, GrazianoObertelli, Sunil Soman, Lamia Youseff, DmitriiZagorodnov, in Proceedings of 9th IEEE International Symposium on Cluster Computing and the Grid, Shanghai, China

Web services – Big Picture

Axis2 – SOAP Processing Model

Axis2 Engine
Axis2 - Components
Tools
WSDL CodeGeneration
Handlers
Transports
Information Model
Deployment Model
XML Model

XML Model
AXIOM (AXIs Object Model)
API is more like simplified DOM
Fundamental Difference
Data read and objects created on-demand using pull parsers
Allows direct access to the underlying pull stream with or without building the tree
Support for storing binary data
API also provides a StAX parser interface at any element
Allows the event based navigation of the OM tree.

Build object model to here
h = envelope.getHeader(securityQName)
...and then you can do
body = envelope.getBody();
reader = body.getXMLStreamReader();
while (reader.hasNext()) {
...
}
AXIOM Architecture- Deferred Building
<soap:Envelope>
<soap:Header>
<myNS:Securitysoap:mustUnderstand=“true”>
</myNS:Security>
</soap:Header>
<soap:Body>
<doSomethingCool>
... MEGABYTES OF DATA HERE ...
</doSomethingCool>
</soap:Body>
</soap:Envelope>

Phases, Modules, Handlers

Extensible Messaging Engine

Message Processing Stages
Transport Receivers
Dispatching
AddressingBasedDispatcher
RequestURIBasedDispatcher
SOAPActionBasedDispatcher
SOAPMessageBodyBasedDispatcher
User Handlers
Message Receivers

Dispatching …..
POST /axis2/services/EchoXMLService/echoOMElementHTTP/1.1
User-Agent: Axis2
Host: 127.0.0.1
Content-Type: application/soap+xml; charset=UTF-8;action="EchoOMElement";
.....................
<?xml version='1.0' encoding='UTF-8'?>
<soapenv:Envelopexmlns:soapenv="http://www.w3.org/2003/05/soap-envelope"
xmlns:wsa="http://www.w3.org/2005/08/addressing">
<soapenv:Header>
<wsa:To>http://127.0.0.1:5556/axis2/services/EchoXMLService/echoOMElement</wsa:To>
<wsa:ReplyTo>
<wsa:Address>http://www.w3.org/2005/08/addressing/anonymous</wsa:Address>
</wsa:ReplyTo>
<wsa:MessageID>urn:uuid:AD147449058471C81E11506120248601</wsa:MessageID>
<wsa:Action>urn:EchoOMElement</wsa:Action>
</soapenv:Header>
<soapenv:Body>
<ns1:echoOMElement xmlns:ns1="http://org.apache.axis2/xsd">
<ns1:myValue>Isaac Asimov, The Foundation Trilogy</ns1:myValue>
</ns1:echoOMElement>
</soapenv:Body>
</soapenv:Envelope>

Message Receiver
The last handler of the execution chain
MEP dependent (MEP ?? )
Does the actual business logic invocation
Ability to write custom Message Receivers
Injects dependencies to services
Default Message Receivers
RawXMLINOnlyMessageReceiver
RawXMLINOutMessageReceiver
RPC*MessageReceiver

Message Exchange Patterns - MEP
Describes the exchange pattern of SOAP messages per given operation
In-Out
In only
In optional out

Information Model

Deployment Model
Axis 1.x deployment requires you to
modify the XML files or
Call the admin client, add to the classpath, restart the server
Archive based deployment
Bundle all together and drop in
Directory based deployment (similar structure as archive )
Hot Deployment
Archive file can contain
Class files, third party libraries, any other resources required by the service

Deployment Model – Axis2 Service
Can be deployed as an archive (.aar) file or as a directory with all necessary resources
Isolated – separate Class loader

Deployment Model – Axis2 Service
Service configurations are given by the services.xml
No need to have a WSDL around to be a valid service !!!
Contains
Exposed transports
Service scopes
Action mappings and message receivers
Modules to be engaged

Deployment Model – Axis2 Module
<module name="addressing">
<Description></Description>
<InFlow>
<handler name="AddressingFinalInHandler"
class="org.apache.axis2.handlers.addressing.AddressingFinalInHandler">
<order phase="PreDispatch"/>
</handler>
..............
</InFlow>
<OutFlow>
<handler name="AddressingOutHandle”
class="org.apache.axis2.handlers.addressing.AddressingOutHandler">
<order phase="MessageOut"/>
</handler>
</OutFlow>
<OutFaultFlow>
.............
</OutFaultFlow>
<InFaultFlow>
.............
</InFaultFlow>
</module>

Client Interaction API
Supports both blocking and non-blocking invocations models
Concept of callbacks for the client for non- blocking case
handle both transport dependent and transport independent asynchrony
sendRobust
fireAndForget
sendReceive
sendReceiveNonBlocking

Code Generation
Generates Java/C and other language stubs from given WSDL files
for invoking a Web service
Stub, callback handler, data bound classes, build file
For authoring a Web service
Skeleton, custom message receiver, services.xml

How WS Projects Fit Together
Apache Axis2 Java/C implementations
WS-Commons
Axiom – the XML object model
XmlSchema – Xml schema model used within code generation, WSDL models
Transports
Neethi – WS-Policy implementation
Modules
Sandesha – WS-Reliable Messaging implementation
Rampart, Rahas – WS-Security, WS-Secureconversation, WS-Security Policy, WS-Trust implementations
Savan– WS-Eventing implementation
WS-Addressing
WSS4j – Web services security implementation including XML security
Woden – WSDL 2.0 object model

Resources
Latest Information
http://ws.apache.org/axis2
Feedback, bugs, questions
axis-user@ws.apache.org, axis-dev@ws.apache.org

What’s Next?
Axis2 in the real world
Axis2 hands on
Axis2 Security

Thank You !!
All committers and users who contributed to make Axis2 the best open source Web service engine
Special thanks to DeepalJayasinghe for sharing his slides
Data-to-insight lab for making this talk possible

Questions !!

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Axis2 Landscape

by Eran Withana on Nov 05, 2009

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Axis2 Landscape — Presentation Transcript