110

Handling XML Documents in a Web Service

"tns:PurchaseOrderService_submitPurchaseOrderResponse"/>

...

Code Example 3.19

Mapping XML document to 

xsd:anyType

A WSDL mapping of the XML document type to 

xsd:anyType

 requires the

platform to map the document parameter as a 

javax.xml.soap.SOAPElement

object. For example, Code Example 3.20 shows the Java interface generated for

the WSDL description in Code Example 3.19.

public interface PurchaseOrderService extends Remote {

public String submitPurchaseOrder(SOAPElement 

purchaseOrderXMLDoc) throws RemoteException;

}

Code Example 3.20

Java Interface for WSDL in Code Example 3.19

In this example, the 

SOAPElement

 parameter in 

submitPurchaseOrder

 repre 

sents the SOAP document fragment sent by the client. For the travel agency ser 

vice, this is the purchase order. The service can parse the received SOAP

document fragment using the 

javax.xml.soap.SOAPElement

 API. Or, the service

can use JAXB to map the document fragment to a Java 

Object

 or transform it to

another schema. A client of this Web service builds the purchase order document

using the client platform specific API for building SOAP document fragments 

on the Java platform, this is the 

javax.xml.soap.SOAPElement

 API and sends

the document as one of the Web service's call parameters.

When using the WSDL to Java approach, you can directly map the document

to be exchanged to its appropriate schema in the WSDL. The corresponding gen 

erated Java interface represents the document as its equivalent Java 

Object

. As a

result, the service endpoint never sees the document that is exchanged in its origi 

nal document form. It also means that the endpoint is tightly coupled to the docu 

ment's schema: Any change in the document's schema requires a corresponding

change to the endpoint. If you do not want such tight coupling, consider using

xsd:anyType

 to map the document.