WS:Introduction

Fig: Service Using Without WebService

Fig: WebService[Cross PlateForm Client-Server Communication]

Fig: Client-UDDI-End_Point_Service_Location

Importatnt Elements Of WSDL:-

There are five main elements of WSDL(wiz-dull) file which are given below:-

1-Service

2-Binding

3-Port Type

4-Message

5-Types

Fig:- High Level Architecture: WSDL

Here ,Sample of WSDL file is given below and also each main elements has been explained:-

<?xml version="1.0" encoding="UTF-8"?> <wsdl:definitions targetNamespace="http://jeetendra.developerstpoint.com" xmlns:apachesoap="http://xml.apache.org/xml-soap" xmlns:impl="http://jeetendra.developerstpoint.com" xmlns:intf="http://jeetendra.developerstpoint.com" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:wsdlsoap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <!--WSDL created by Apache Axis version: 1.4 Built on Apr 22, 2006 (06:55:48 PDT)--> <b><wsdl:types></b> <schema elementFormDefault="qualified" targetNamespace="http://jeetendra.developerstpoint.com" xmlns="http://www.w3.org/2001/XMLSchema"> <element name="add"> <complexType> <sequence> <element name="number1" type="xsd:int"/> <element name="number2" type="xsd:int"/> </sequence> </complexType> </element> <element name="addResponse"> <complexType> <sequence> <element name="addReturn" type="xsd:int"/> </sequence> </complexType> </element> </schema> </wsdl:types> <wsdl:message name="addRequest"> <wsdl:part element="impl:add" name="parameters"> </wsdl:part> </wsdl:message> <wsdl:message name="addResponse"> <wsdl:part element="impl:addResponse" name="parameters"> </wsdl:part> </wsdl:message> <wsdl:portType name="Addition"> <wsdl:operation name="add"> <wsdl:input message="impl:addRequest" name="addRequest"> </wsdl:input> <wsdl:output message="impl:addResponse" name="addResponse"> </wsdl:output> </wsdl:operation> </wsdl:portType> <wsdl:binding name="AdditionSoapBinding" type="impl:Addition"> <wsdlsoap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/> <wsdl:operation name="add"> <wsdlsoap:operation soapAction=""/> <wsdl:input name="addRequest"> <wsdlsoap:body use="literal"/> </wsdl:input> <wsdl:output name="addResponse"> <wsdlsoap:body use="literal"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:service name="AdditionService"> <wsdl:port binding="impl:AdditionSoapBinding" name="Addition"> <wsdlsoap:address location="http://localhost:8080/WSSOAP/services/Addition"/> </wsdl:port> </wsdl:service> </wsdl:definitions>

1:-service

Service element defines where the service can be accessed. Each service is associated with a unique name which is suggested by <wsdl:service name="AdditionService"> in our example. The next element <wsdl:port binding="intf:AdditionSoapBinding" name="Addition"> suggests the previous binding which will be used by service. The element <wsdlsoap:address location="http://localhost:8080/WSSOAP/services/Addition"/>suggests the physical address through which a service can be accessed.

2:-bindings

A binding defines message format and protocol details for operation and message defined by each portType. Each binding element is identified by a unique name attribute which can be any user defined name. The typeelement defines the portType referenced by binding. In our case <wsdl:binding name= "AdditionSoapBinding" type="intf:Addition"> defines a binding with a unique name and Addition portType associated with it. The soap:binding element has style attribute which can be either RPC-oriented(messages containing parameters and return values) or document-oriented(message containing documents). The default value for this element is document. The other element is transport which suggests the transmission protocol used. In our example we have <wsdlsoap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>document as the style and http as the transport protocol. <wsdl:operation name="add"> name defines operation associated with each portType. Each operation will have a a soapAction associated with it. <wsdl:input name="addRequest"> define the input for the operation and <wsdlsoap:body use="literal"/> defines the encoding standard. In our example we are using literal as the encoding standard.

3:-portType

<h5><b>This basically involves a set of operation and messages involved in each operation. <portType name=""> defines a unique name. In our example <wsdl:portType name="Addition"> suggest a unique name. Each portType has an associated <operation name=""> element which suggest an operation name. In our example <wsdl:operation name="add"> suggests an operation name. Each operation element can have <input>, <output> or both the tags accordingly it will be one-way, notification or request-response operation. Our example has <wsdl:input message="intf:addRequest" name="addRequest"/> which uses the addRequest as the input message and <wsdl:output message="intf:addResponse" name="addResponse"/> which uses the addResponse as the output message.</b></h5>

4:-message

This element defines the various messages used by the Web service. In our example we have two message name, addRequest which is associated with add data type and addResponse which is associated with addResponse data type as defined in the <types> element. Each message type has unique name which is suggested by <message name=""> tag. The <part element="" ...> suggests the data type associated with each message. <part> element can be considered as a parameter to a function call.

5:-types

Web Service is all about sending and receiving messages. The <types> element describes the various messages which will be used by the service. Basically it defines the various data types. As can be seen, add service uses hello and addResponse as the two messages.