Working with Web Services - Beginning Java 7 - page 1100

• SOAPEnvelope optionally contains a SOAPHeader instance and also con-
tains a mandatory SOAPBody instance.
• SOAPHeader represents the SOAP message's header block(s).
• SOAPBody contains either a SOAPFault object or a SOAPBodyElement
object containing the actual SOAP payload XML content.
• SOAPFault stores a SOAP fault message.
WorkingwithSAAJinvolvescreatingaSOAPconnection,creatingSOAPmessages,
populatingeachmessagewithcontentandoptionalattachments, sendingthemessages
to an endpoint, and retrieving replies.
You create a connection by working with the SOAPConnectionFactory and
SOAPConnection classes. As its name implies, SOAPConnectionFactory is a
factory class for retrieving SOAPConnection instances (actually, instances of sub-
classesoftheabstract SOAPConnection class).A SOAPConnection instancerep-
resents an endpoint-to-endpoint connection to the web service; the client and web ser-
vice exchange messages over this connection. The following example shows you how
to instantiate the factory and obtain a SOAP connection:
SOAPConnectionFactory soapcf = SOAPConnectionFact-

ory.newInstance();
SOAPConnection soapc = soapcf.createConnection();
Instantiate the factory by calling SOAPConnectionFactory 's SOAPConnec-
tionFactory newInstance() method.Thismethodthrows SOAPException
whena SOAPConnectionFactory instancecannotbecreated.IfanonOracleJava
implementation doesn't support the SAAJ communication infrastructure, this method
throws an instance of the java.lang.UnsupportedOperationException
class.
After instantiating SOAPConnectionFactory , call this instance's SOAPCon-
nection createConnection() method tocreate andreturn anew SOAPCon-
nection object.Thismethodthrows SOAPException whenit'sunabletocreatethis
object.
Create a SOAP message by working with the MessageFactory and SOAPMes-
sage classes. MessageFactory provides a pair of methods for returning a Mes-
sageFactory instance:
• MessageFactory newInstance() createsa MessageFactory object
basedonthedefaultSOAP1.1implementation.Thismethodfollowsanordered
lookupproceduretolocatethe MessageFactory implementationclass.This