Axis2 Landscape

Eran ChinthakaSchool 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 UsageCompanies 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, Graziano Obertelli, Sunil Soman, Lamia Youseff, Dmitrii Zagorodnov, 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

Information Model

XML Model

Handlers

Deployment Model

Transports

ToolsWSDL CodeGeneration

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.

AXIOM Architecture- Deferred Building

<soap:Envelope>

<soap:Header>

<myNS:Security soap:mustUnderstand=“true”>

</myNS:Security>

</soap:Header>

<soap:Body>

<doSomethingCool>

... MEGABYTES OF DATA HERE ...

</doSomethingCool>

</soap:Body>

</soap:Envelope>

...and then you can dobody = envelope.getBody();

reader = body.getXMLStreamReader();

while (reader.hasNext()) { ...}

Build object model to here

h = envelope.getHeader(securityQName)

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/echoOMElement HTTP/1.1User-Agent: Axis2Host: 127.0.0.1Content-Type: application/soap+xml; charset=UTF-8;action="EchoOMElement";.....................

<?xml version='1.0' encoding='UTF-8'?><soapenv:Envelope xmlns: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 Deepal Jayasinghe for sharing his slides

• Data-to-insight lab for making this talk possible

Questions !!