222

Developing Client Applications to Use a Web Service

OrderTrackingIntf port = (

OrderTrackingIntf)ots.getPort(new QName(

"urn:OpcOrderTrackingService", "OrderTrackingIntfPort"),

OrderTrackingIntf.class);

...

Code Example 5.5

J2SE Client Dynamic Proxy Service Lookup

Code Example 5.5 illustrates how a J2SE client might program to interfaces

that are portable across JAX RPC runtimes. It shows how a J2SE client uses a

ServiceFactory

 to look up and obtain access to the service, represented as a

Service

 object. The client uses the qualified name, or 

QName

, of the service to

obtain the service's port. The WSDL document defines the 

QName

 for the service.

The client needs to pass as arguments the 

QName

 for the target service port and the

client side representation of the service endpoint interface. 

By contrast, Code Example 5.6 shows how a J2EE client might use a dynamic

proxy to look up and access a service. These two examples show how much

simpler it is for J2EE clients to look up and access a service than it is for J2SE cli 

ents, since a JNDI lookup from the 

IntialContext

 of an existing service is much

simpler than configuring the parameters for 

ServiceFactory

. The J2EE client just

invokes a 

getPort

 call on the client side representation of the service endpoint

interface.

Context ic = new InitialContext();

Service ots =

(Service) ic.lookup(

"java:comp/env/service/OpcOrderTrackingService");

OrderTrackingIntf port = (OrderTrackingIntf)ots.getPort(

OrderTrackingIntf.class);

Code Example 5.6

Using a Dynamic Proxy in a J2EE Environment

A J2SE client using the DII approach might implement the code shown in

Code Example 5.7 to look up the same service at runtime. DII communication

supports two invocation modes: synchronous and one way, also called fire and

forget. Both invocation modes are configured with the 

javax.xml.rpc.Call

object. Note that DII is the only communication model that supports one way