Chapter 5 Client Design

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This exception mapping mechanism may not be used with DII, since this

communication mode returns all exceptions as 

java.rmi.RemoteException

. Note

that there is no guarantee that the JAX RPC runtime system will throw a

ServiceException

 for a specific 

wsdl:fault

 error. The runtime may instead

throw a 

javax.xml.rpc.soap.SOAPFaultException

 runtime exception.

Use the JAX RPC tools to map faults to Java objects. (See  WSDL to Java

Type Mapping  on page 225.) These tools generate the necessary parameter map 

pings for the exception classes and generate the necessary classes for the map 

ping. Generated exceptions classes extend 

java.lang.Exception

. The client

application developer is responsible for catching these checked exceptions in a

try

/

catch

 block. The developer should also try to provide the appropriate applica 

tion functionality to recover from such exceptions. For example, an order tracking

client might include the code shown in Code Example 5.15 to handle cases where

a matching order is not found. The order tracking service threw an

OrderNotFoundException

, and the client presented the user with a GUI dialog

indicating that the order was not found.

try {

OrderDetails od = service.getOrderDetails(orderId); 

} catch (OrderNotFoundException onx) {

JOptionPane.showMessageDialog(gui, 

"Order Not found with Order ID " + orderId, "Error",

JOptionPane.ERROR_MESSAGE);

}

Code Example 5.15

J2SE Client Displaying an Error

A J2EE Web component client may handle the exception using the facilities

provided by the J2EE environment. The client may wrap the application exception

and throw an unchecked exception, such as a 

javax.servlet.ServletException

,

or it may map the exception directly to an error page in the Web deployment

descriptor. In Code Example 5.16, the client maps the 

OrderNotFoundException

directly to a JSP. Clients should always provide human readable messages and

give the user the ability to return to an entry page.

com.sun.blueprints.adventure.

OrderNotFoundException