Patterns: Implementing Self-Service in an SOA Environment

Chapter 10. Web services scenario 331

createSIDestinationAddress(newDestination,busName);

frp.clear();

frp.add(newAddress);

message.setForwardRoutingPath(frp);

}

return true;

}

}

10.6.3 Extending the mediations

The techniques in this simple example illustrate how to manipulate messages in

a mediation. The code as written will work if you only expect two responses.

You can extend this example to manage more than two responses by adding a

queue to contain control data that indicates how many messages were sent out.

This information is used by the aggregator to know how many responses to

expect. For an example of this, see the broker scenario in Patterns: SOA with an

Enterprise Service Bus in WebSphere Application Server V6, SG24-6494.

Another element to consider is how long to wait for a response from each

service. This example waits indefinitely, but it would be reasonable include code

that handles a situation where not all responses are received within a time limit.

10.7 Runtime guidelines for Web services

This section describes how to configure the service integration bus for Web

services. We first look at the Web services support provided in WebSphere

Application Server. We then go into specific configuration tasks required to run

the sample application.

10.7.1 Web services support in WebSphere Application Server V6

WebSphere Application Server can act as both a Web service provider and as a

requester. As a provider, it hosts Web services that are published for use by

clients. As a requester, it hosts applications that invoke Web services from other

locations. WebSphere Application Server supports SOAP-based Web service

hosting and invocation.

WebSphere Application Server V6 provides J2EE 1.4 support, including Web

services 1.1.

򐂰 JAX-RPC v1.0 for J2EE 1.3, v1.1 for J2EE 1.4

򐂰 JSR 109 (Web services for J2EE)

332 Patterns: Implementing Self-Service in an SOA Environment

򐂰 WS-I Basic Profile 1.1.2 support

򐂰 WS-I Simple SOAP Binding Profile 1.0.3

򐂰 WS-I Attachments Profile 1.0

򐂰 SAAJ 1.2

򐂰 UDDI V2 and V3

򐂰 JAXR

򐂰 WS-TX (transactions)

򐂰 SOAP 1.1

򐂰 WSDL 1.1 for Web services

򐂰 WSIL 1.0 for Web services

򐂰 OASIS Web Services Security: SOAP Message Security 1.0 (WS-Security

2004)

򐂰 OASIS Web Services Security: UsernameToken Profile 1.0

򐂰 OASIS Web Services Security X.509 Certificate Token Profile

WebSphere Application Server also provides an integrated private UDDI V3

registry and in the Network Deployment package, integrated Web Services

Gateway function.

Web services and the service integration bus

Also new, is the ability to use the service integration bus as an intermediary

between service requestors and service providers, allowing control over the flow,

routing, and transformation of messages through mediations and JAX-RPC

handlers. The bus provides a flexible way to expose and call services located in

an intranet from the Internet (and vice versa), while also providing mechanisms

for protocol switching and security.

The use of Web services with the bus is an evolution of the Web Services

Gateway provided in WebSphere Application Server V5. Whereas the Web

Services Gateway was a stand-alone application in V5, the bus is more tightly

integrated into the application server, enabling users to take advantage of

WebSphere Application Server administration and scalability options, and also

build on top of the asynchronous messaging features provided by WebSphere

Application Server.

The bus enables users to specify a level of indirection between service

requestors and providers by exposing existing services at new destinations. It

also provides options for managing these services through

mediations, which

can access and manipulate incoming and outgoing message content, or even

route the message to a different service. Support for JAX-RPC handlers is also

included in the bus, as is Web services gateway functionality.

While all WebSphere Application Server packages can use the bus as a

destination point for Web services, the Web Services Gateway function is only

available in the Network Deployment package.