Chapter 5 Client Design

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application may set the properties on the 

Call

 interface. See Code Example 5.7,

which illustrates setting these properties.

E

J2EE client developers should avoid setting properties other than the 

javax.xml.rpc.endpoint.address

 property.

E

Avoid setting nonstandard properties if it is important to achieve portability 

among JAX RPC runtimes. Nonstandard properties are those whose property 

names are 

not

 preceded by 

javax.xml.rpc

.

E

Avoid using 

javax.xml.rpc.session.maintain

 property. This property per 

tains to a service's ability to support sessions. Unless you have control over the 

development of both the client and the endpoint, such as when both are devel 

oped within the same organization, you cannot be sure that the Web service 

endpoints support sessions, and you may get into trouble if you set this prop 

erty incorrectly.

5.3.4 WSDL to Java Type Mapping 

When working with Web services, there may be differences between the SOAP 

defined types (defined in the WSDL document) used by the service and the Java 

defined types used by the client application. To handle these different types, a client

of a Web service cannot use the normal approach and import remote classes.

Instead, the client must map the WSDL types to Java types to obtain the parameter

and return types used by the service. Once the types are mapped, the client has the

correct Java types to use in its code. 

Generally, the JAX RPC runtime handles the mapping of parameters, excep 

tions, and return values to JAX RPC types. When a client invokes a service, the

JAX RPC runtime maps parameter values to their corresponding SOAP represen 

tations and sends an HTTP request containing a SOAP message to the service.

When the service responds to the request, the JAX RPC runtime receives this

SOAP response and maps the return values to Java objects or standard types. If an

exception occurs, then the runtime maps the 

WSDL:fault

 to a Java exception, or to

a 

javax.rmi.RemoteException

 if a 

soap:fault

 is encountered. (This is discussed

further in  Handling Exceptions  on page 230).

The JAX RPC runtime supports the following standard value types: 

String

,

BigInteger

, 

Calender

, 

Date

, 

boolean

, 

byte

, 

short

, 

int

, 

long

, 

float

, 

double

, and

arrays of these types. Services can return mime types as images mapped to the

java.awt.Image

 class and XML text as 

javax.xml.transform.Source

 objects.