Integration Approach

1

• Integration Approach
• AXIS-SOAP
• Web Services

2
Agenda

• Web Services
• SOAP
• Apache-AXIS
• Demonstration

3
Web Services

• Problem
• Need to provide access to selected services to
  clients
• Want to avoid exposing the business logic from
  the client

4
Web Services

• Web accessible, client-service architecture.
• server side offers a clear interface while hiding
  business logic
• client side coding is clients responsibility

Web Server
Business Logic
Client
Servlet
5
Web Services

• Issues
• Providing implementation independent transport
• Publishing the interface

6
SOAP

• Simple Object Access Protocol (SOAP)
• Defines a protocol for the exchange of messages
  (usually over HTTP)
• Platform independent
• Extensive use of XML Namespaces
• Format
• Requires use of xmlnsSOAP
• SOAPEnvelope
• SOAPHeader
• SOAPBody

7
SOAP

• SOAP Sample
• lt?xml version"1.0"?gt
• ltsoapEnvelope xmlnssoap"http//www.w3.org/2001/
  12/soap-envelope" soapencodingStyle"http//www.w
  3.org/2001/12/soap-encoding"gt
• ltsoapHeadergt
• ... ...
• lt/soapHeadergt
• ltsoapBodygt
• ...
• lt/soapBodygt
• lt/soapEnvelopegt

8
SOAP

• Client sends out SOAP encode service request
• ltsoapbodygt
• ltns1AXISIntegrationgt
• ltisPartOfOutagegt
• ltqueryIDgt12345678lt/queryIDgt
• lt/isPartOfOutagegt
• lt/ns1AXISIntegrationgt
• lt/soapbodygt

9
SOAP

• Server recieves the SOAP encoded request
• Extracts the body of the message
• Executes the necessary business logic
• Replies with a SOAP encoded response
• ltsoapbodygt
• ltns1AXISIntegrationgt
• ltisPartOfOutageResponsegt
• response object
• lt/isPartOfOutageResponsegt
• lt/ns1AXISIntegrationgt
• lt/soapbodygt

10
Apache-AXIS

• SOAP Engine
• Publishes webservice interfaces
• Automatic SOAP encoding/decoding
• Automatic Object serialization/deserialization
• Automatic code generation from interfaces

Server Side AXIS
Client Side AXIS
Service
WebServer
Client
11
AXIS

• Server Side Architecture
• Resides on the server as a servlet (web.xml)

User defined Services
AXIS Servlet
Server-config.wsdd
.wsdl
12
AXIS

• Server Side Architecture
• Services are deployed by mappings in the
  server-config.wsdd
• Listens for requests to mapped services invokes
  the appropriate code
• Services are published by an automatically
  generate (or predefined) Web Services Description
  Language (WSDL) file
• Modified either manually or via AXIS Admin
  deployment tool

13
AXIS

• .wsdd sample (part of server-config.wsdd)
• ltservice name"AXISIntegrationServlet"
  provider"javaRPC"gt
• ltparameter name"className" valueltservlet
  classgt"/gt
• ltparameter name"allowedMethods" value""/gt
• lttypeMapping xmlnsnsltcustom type mappinggt
• serializerltcustom serializergt
• deserializerltcustom deserializergt
• ltwsdlFilegtcustom wsdl filelt/wsdlFilegt

14
AXIS

• .wsdl sample
• lt?xml version"1.0" encoding"UTF-8"?gt
• ltwsdldefinitions
• ltwsdltypesgt
• types defined as XML Schemas
• ltwsdlmessage name"isPartOfOutageRequest"gt
• messages their contents definitions
• ltwsdlportType name"AXISIntegrationServlet"gt
• ...binding port types
• ltwsdlbinding name"AXISIntegrationServletSoapBin
  ding" type"implAXISIntegrationServlet"gt
• ..binding messages to servlets
• ltwsdlservice name"AXISIntegrationServletServic
  e"gt
• .. bind services to addresses

15
AXIS

• Automatically (De)Serializes simple types from
  XML to Objects (and vice versa)
• Complex types require custom (De)Serializers
• Complex Type (De)Serialization
• Create custom (De)Serializer for the type
• Map the object to that (De)Serializer
  (server-config.wsdd)

16
AXIS

• Client Side Architecture
• Automatic (De)Serialization
• AXIS stub generation from server provided wsdl

(De)Serializers
AXIS Generated Code
Webservice Consumer
17
AXIS

• In relation to eRespond
• Reside as a servlet on the webserver
• Add in axis libraries to the classpath
• Modify web.xml to include AXIS servlet
• Check provided eRespond/axis.htm

18
AXIS Development

• General steps for development
• Write deploy service class
• Define the.wsdd for that service
• if necessary define custom .wsdl types place on
  the classpath
• deploy the service (modify server-config.wsdd
  manually or via AXIS Admin tool)
• redeploy webapp

19
AXIS Development

• Demonstation service is Part Of Outage
• Recieves a long query premise id
• Searches if the premise associated with that id
  is currently part of an Outage
• If so returns details of that outage
• If not returns null

20
AXIS Development

• Created AXISIntegrationServlet.java
• Implemented method isPartOfOutage(long queryID)
• public Outage isPartOfOutage(long queryID)
• Long query new Long(queryID)
• Outage retOutage null
• creating the actionObjectInterface
• retOutage (Outage) actionObjectInterface.proces
  sMessage(query)
• return retOutage

21
AXIS Development

• Defined .wsdl for method and type Outage
• Created Custom (De)Serializers for type Outage
• Defined .wsdd deployed to the server
• Examined AXISIntegrationServlet?WSDL

22
AXIS Development

• Client Side Development
• Generated Classes using WSDL2Java
• Mapped type Outage to custom (De)Serializers
• Created service consumer code calling on
  generated classes
• public static Outage getOutageFor(long queryID)
• ..call on AXIS generated stubs
• AXISIntegrationServlet test service.getAXISInteg
  rationServlet()
• response test.isPartOfOutage(queryID)
• return response

23
Conclusion

• WebServices allow us to provide external access
  to selected services
• SOAP enables client-server transport
• AXIS Simplifies webservice development
  deployment with
• Service Publishing via WSDL files
• Automatic (De)Serialization
• Client Side code generation