WSDL 2.0 and Apache Woden

Move on to WSDL 2.0 and Apache
Woden

Sagara Gunathunga
Apache Committer

Who am I ?

• Apache Woden Committer
• Also contribute to Apache Axis2 and
Apache Camel .

Outline
• Introduction to SDLs
• Today’s SDLs
• Introduction to WSDL 2.0
• WSDL 2.0 and REST
• Introduction to Apache Woden
• Hands-on Apache Woden
• Apache Woden tools
• What is new in Apache Woden 0.9
• WSDL 2.0 based WS development in Axis2

What is a contract in real world ?

Contract in Web services

WHAT ?
HOW ?

WHERE ?

WHAT it does ?
• Define the purpose and function of its operations.

• Define the messages that need to be exchanged in
order to engage the operations.

• Define data models used to define the structure of the
messages.

• Define a set of conditions under which the operations
are provided.

• Define information about how and where the service
can be accessed.

Today’s SDLs

• WSDL 1.1 ( Web Service Description Language 1.1)

• WADL ( Web Application Description Language)

• SSDL (SOAP Service Description Language)

WSDL 1.1
WSDL is an XML-based language used to define
Web Services and describe how to access them.

WSDL is an XML format for describing network services as
a set of endpoints operating on messages containing either
document-oriented or procedure-oriented style.

WSDL 1.0 was Jointly developed by IBM, Microsoft and
many others in 2000.

WSDL 1.1 released in 2001.

Compliant with WSDL Basic profile 1.0

WSDL 1.1
Pros
• Proven and Widely used in industry for last few years.

• Compliant with WS-I basic profile 1.0
• Many projects available - WSDL4J , WOM
• Code generation tools available –
Axis2 /CXF WSDL2Java ,wsimport

Cons
• Really complex language.
• Hard learning curve.
• Not fit with REST services.

WADL
WADL is a description language for HTTP-based Web
applications, such as applications which follow the
REST architectural style.

Written by Marc Hadley at Sun somewhere around
2006.
From August 2009 WADL is a W3C Member
Submission.

Pros
• Works well with REST services.

• Automation tools available -
WADL2JAVA , Google REST compiler
• Some projects available - Jersey

Cons
• Still not widely used as WSDL 1.1

• Doesn't support for SOAP based web services.

SSDL
The SOAP Service Description Language (SSDL) is a
SOAP-centric contract description language for Web
Services

Pros
• Works well with SOAP based web services.
• Project available - Soya for C#

Cons
• Not widely used in neither industry nor academic purposes.
• Only support for SOAP.
• No automation tools available .
• No project for java.

Outline
• Introduction to SDLs
• Today’s SDLs
• Introduction to WSDL 2.0
• Introduction to Apache Woden
• WSDL 2.0 and REST
• Hands-on Apache Woden
• Apache Woden tools
• What is new in Apache Woden 0.9
• WSDL 2.0 based WS development in Axis2

WSDL 2.0
• Improved version of WSDL 1.1

• Simple and no ambiguities unlike WSDL 1.1 and easy
learning curve.

• Fully supports for both SOAP based and RESTful web
services.

• Removal of message constructs. These are specified
using the XML schema type system.

• Possibility to define QoS – features and properties

WSDL 2.0
• Well defined Message Exchange Patterns (MEP)

• Some WS engines already supports and provide
automation tools
- Axis2 and WSDL2Java

Wsdl1.1/2.0 Comparison
WSDL 1.1 WSDL 2.0
<definition> <description>
<portType> <interface>
<binding> <binding>
<types> <types>
<service> <service>
<port> <endpoint>
<message> Within <operation>

WSDL 2.0 component model

Description is container for 2 types of top-level components.
(1) WSDL Component (interface , binding , services)
(2) Type system component
(ElementDeclaration,typeDefinition)

WSDL 2.0 nested component
model

Feature & property
Provides additional processing information for a component
example – reliability , correlation

MEP – Message Exchange
patterns
MEP defines a contract between service and client
WSDL 2.0 defines 8 MEPs

• In-Only
• Robust In-Only
• In-Out
• In-Optional-Out
• Out-Only
• Robust Out-Only
• Out-In
• Out-Optional-In

WSDL 2.0 and REST
The "WSDL 2.0 Part 2: Adjuncts" provides the specifics of
HTTP, SOAP 1.2, and MEP usage with WSDL 2.0. WSDL
2.0 HTTP Binding can be used to define REST services
successfully.

Following HTTP methods can be used.
7. GET
8. POST
9. PUT
10.DELETE

WSDL 2.0/ HTTP Binding
Binding type should be http://www.w3.org/2006/01/wsdl/http
<binding
name="xs:NCName"
interface="xs:QName"?
type="http://www.w3.org/ns/wsdl/http"
whttp:methodDefault="xs:string"?
whttp:queryParameterSeparator
Default="xs:string"?
whttp:cookies="xs:boolean"?
whttp:contentEncodingDefault="xs:string"? >

WSDL 2.0/ HTTP Binding
<operation ref="xs:QName"
whttp:location="xs:anyURI"?
whttp:method="xs:string"?
whttp:inputSerialization="xs:string"?
whttp:outputSerialization="xs:string"?
whttp:faultSerialization="xs:string"?
whttp:queryParameterSeparator="xs:string"?
whttp:contentEncodingDefault="xs:string"?
whttp:ignoreUncited="xs:boolean"? >

In most cases “location” and “method” attributes are
sufficient .

Example

<wsdl2:binding name="DemoServiceHttpBinding"
interface="tns:DemoServiceInterface"
type=http://www.w3.org/ns/wsdl/http >

<wsdl2:operation
ref="tns:demo"
whttp:method="POST"
whttp:location="demo“ />
</wsdl2:binding>

Input and Output Serialization
Formats
Input format - {http input serialization}
Output format - {http output serialization}

HTTP Method Default Input Default Output
Serialization Serialization
GET application/x-www- application/xml
form-urlencoded
POST application/xml application/xml

PUT application/xml application/xml

DELETE application/x-www- application/xml
form-urlencoded

Apache Woden

Apache Web Services Project to develop a
Java class library for reading, manipulating,
creating and writing WSDL documents, initially
to support WSDL 2.0 but with the longer term
aim of supporting past, present and future
versions of WSDL.
Who uses Woden
- Apache Axis2
- Apache ServiceMix

Main deliverables
1. Woden API for WSDL 2.0
2. DOM based implementation.
3. OM (Axiom) based implementation.
4. WSDL 2.0 validator tool
5. WSDL1.1 to 2.0 Converter tool.
6. Maven plug-ins and Ant Tasks for above tools

Two APIs
Component model API
•Mirror the component model of WSDL 2.0

•One root Description object representing a merge of all
.wsdl files imported and included

Element level API
Mirror the XML representation of WSDL 2.0

Represent the physical Xml file representation

Component level – Element
level
To Component model To Element model
aElement.toComponent() aComponent.toElement()

Example
DescriptionElement descElement;
Description descComponent;

descComponent=descElement.toComponent();
descElement=descComponent.toElement();

Define the implementation
DOM or OM
Using WSDLFactory you can specify the implementation.
Default implementation is based on DOM
For DOM implementation
WSDLFactory FWSDLFactory=WSDLFactory.newInstance();
OR
WSDLFactory FWSDLFactory=
WSDLFactory.newInstance(“org.apache.woden.internal.DOMWSDLFactory”);

For OM implementation
WSDLFactory FWSDLFactory=

WSDLFactory.newInstance(“org.apache.woden.internal.OMWSDLFactory”);

Reading WSDL 2.0 documents

// create WSDL factory instance.

//create WSDL reader instance
WSDLReader reader=FWSDLFactory.newWSDLReader();

//set validation
reader.setFeature(WSDLReader.FEATURE_VALIDATION, true);

//read the WSDL file in to a DescriptionElement
DescriptionElement descElem = reader.readWSDL(wsdlurl);

Writing WSDL 2.0 document
// create WSDL factory instance.

//create WSDL writer instance
WSDLWriter writer=FWSDLFactory.newWSDLWriter()

//Write WSDL in to the console
writer.writeWSDL(descElem, System.out )

//write WSDL as a file
writer.writeWSDL(descElem, new FileOutputStream("test.wsdl") )

create WSDL document
At the moment only support for Element level API

WSDLFactory wsdlFactory=WSDLFactory.newInstance();

DescriptionElement descElement=wsdlFactory.newDescription();
descElement.setTargetNamespace(new URI("http://my.com") );

InterfaceElement interElement=descElement.addInterfaceElement();
InterfaceOperationElement
iOpElement=interElement.addInterfaceOperationElement();

BindingElement bindingElement=descElement.addBindingElement();
BindingOperationElement
bOpElement=bindingElement.addBindingOperationElement();

Woden tools - validation
• Schema validations done by the XML parsers.

• Semantic validations done by Woden validator.
- on the WSDL object model assertions are checked
against the model.

• All errors are reported in one pass. Woden does not
stop-on-first-error like WSDL4J.

Woden tools - Validation

Validation is ‘off’ by default.
Enable validation before reading the WSDL

Example

reader.setFeature(WSDLReader.FEATURE_VALIDATION, true);

Woden tools - WSDL Converter
• Perform WSDL 1.1 to 2.0 conversion.
• Another great feature.
• Based on XSLT style sheet.
• Available as a Standalone tool, as a Maven plug-in or an
Ant Task

Woden tools - WSDL Converter
In command line

java -Djava.ext.dirs=/home/sagara/woden
org.apache.woden.tool.converter.Convert
-wsdl /home/sagara/test/converter/Echo.wsdl

programmatically

Convert convert = new Convert();
try {
convertFile =
convert.convertFile(newTargetNS,wsdlDoc,
targetDir,verbose,overwrite);
System.out.println(convertFile);
} catch (Exception e) {
e.printStackTrace();
}

What is new in Woden 0.9
• Woden Serialization - WSDLWriter based on DOM and
OM.

• Split QName into a different package to resolve conflicts in
OSGI environments.

• Remove dependency on Xereces , now Woden(dom) work
with any JAXP implementation

• Component level equals method.

• Logging framework based on Commons-logging API.

• WSDL Converter Maven plug-in and Ant Task

• Code base refactored for more Maven friendly manner .

WSDL 2.0 based WS development
in Axis2
Axs2 supports for WSDL 2.0
1.) Contract first Web services.
2.) Code first services

in Axis2
In Contract first WS development you can use Axis2
WSDL2JAVA tool to generate source codes from your
WSDL 2.0 documents.
Both WSDL2JAVA Ant Task and Maven Plug-in supports
for WSDL 2.0
In WSDL2JAVA Command line tool use -wv 2 or -wv 2.0
options. With Maven Plug-in use wsdlVersion option.
Example :

wsdl2java -wv 2 OR wsdl2java -wv 2 .0

in Axis2
In code first approach, to generate WSDL 2.0 document
use ?wsdl2 instead of ?wsdl .

Example :

http://localhost:8080/services/SimpleService?wsdl2

Contribution
• Site : http://ws.apache.org/woden/

• Mailing list : woden-dev@ws.apache.org

WSDL 2.0 and Apache Woden

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