Java Reference
In-Depth Information
}
}
whichisprefixedwith
@WebServiceProvider
,
@ServiceMode
,and
@Binding
annotations.
@WebServiceProvider
specifiesthat
Library
isawebserviceendpointclass
implementingthe
javax.xml.ws.Provider<T>
interface(analternativetoanSEI
for services that need to work at the XML message level) in terms of its
T in-
voke(T request)
method. The actual type argument passed to type parameter
T
identifies the source of request and reponse data, and is one of
javax.xml.transform.Source
,
javax.activation.DataSource
, or
javax.xml.soap.SOAPMessage
.ForaRESTfulwebserviceprovider,youwould
specify
Source
or
DataSource
for
T
.
Note
Although you can process SOAP messages directly with a web service pro-
vider,itiscommontoignorethesemessagesbyworkingwith
@WebService
—an-
notatedSEIsandSIBs,aspreviouslydiscussed.Also,youcanworkwithSOAPmes-
sages from an API perspective by using the SAAJ API, which I present later in this
chapter.
WhenarequestismadetotheRESTfulwebservice,theproviderclass's
invoke()
methodiscalledwithasourceofbytes,suchasa
POST
request'sXMLdocument.The
invoke()
methodrespondstotherequestinsomeappropriateway,returningasource
of bytes in XML format that form the service's response. This method throws an in-
stanceofthe
WebServiceException
runtimeexceptionclassoroneofitsdescend-
ent classes (e.g.,
javax.xml.ws.http.HTTPException
) when something goes
wrong.
Note
A class annotated with
@WebService
exposes a separate method for each
webserviceoperation.Forexample,
TempVerter
exposes
c2f()
and
f2c()
meth-
ods for the Celsius-to-Fahrenheit and Fahrenheit-to-Celsius messages. In contrast,
@WebServiceProvider
exposesasingle
invoke()
methodtohandleallopera-
tions.
@ServiceMode
specifiesthat
Library
's
invoke()
methodreceivesentirepro-
tocol messages (instead of message payloads) by having its
value()
element ini-
tializedto
javax.xml.ws.Service.Mode.MESSAGE
.Whenthisannotationisn't
present,
value()
defaults to
javax.xml.ws.Service.Mode.PAYLOAD
.
