JAX-WS 2.0 Provider-based endpoints explained!

Jitu implemented the support
for Provider-based endpoints in JAX-WS RI.
Without undermining the wonderful effort of JAX-WS esteemed spec leads, here is
an attempt to capture a whiteboard discussion on Provider-based endpoints
possible combinations that Jitu
and I had last Friday afternoon.

JAX-WS 2.0 introduces javax.xml.ws.Provider
interface that is an alternative to a Java service endpoint interface (SEI)
based endpoint. It is used if the services need to work at the XML message
level.

A Provider-based endpoint can receive data in javax.xml.transform.Source,
javax.activation.DataSource
or javax.xml.soap.SOAPMessage
formats. It can work in either payload or message mode.
JAX-WS specification has a conformance requirement (Provider support required)
that defines the combinations of the Provider type, the mode and SOAP/HTTP or
XML/HTTP binding. Additionally, the message on the service endpoint may be
received as SOAP message (does not matter 1.1
or 1.2) or a mime
multipart message. The table below summarizes the requirement with all the
possible combinations.

Provider<Source> may receive a mime multipart message or an XML
message. If it is a mime multipart message, then the primary part for XML/HTTP
and SOAP Envelope for SOAP/HTTP is extracted and converted to the Source for
payload mode. The primary part, in the case of mime multipart message, must
contain XML data for XML/HTTP binding. If it is an XML message then the content
for XML/HTTP (irrespective of mode) is converted to the Source. The XML message
is converted to SOAP message and SOAP Body or Envelope for SOAP/HTTP (depending
upon the mode) is converted to the Source.

[1] Provider<DataSource> is used for sending
attachments and thus payload mode is not valid.

[2] Provider<DataSource> in SOAP/HTTP is not valid
since attachments in SOAP are sent using Provider<SOAPMessage>.

[3] Provider<SOAPMessage> in payload mode is not
valid because the entire SOAPMessage is received, not just the payload which
corresponds to the body of the SOAPMessage.

[4] Provider<SOAPMessage> in message mode using
XML/HTTP binding is not valid since the client may have sent an XML message that
may not be SOAP.

Provider<Source>-based endpoints using XML/HTTP binding allows you to
develop and deploy RESTful Web services with JAX-WS 2.0. Read Marc
Hadley's blog
for more details.

I'll provide a similar explanation on Dispatch-based
clients, used to invoke RESTful Web service, in a subsequent blog.

JAX-WS is available in Glassfish.

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