WS-Reliable Messaging and Session Support (Part3)
Posted by bhaktimehta on June 7, 2007 at 10:23 AM PDT
This is the third part of tri series blogs where in Part 1 we showed
one way
of supporting sessions with
WS Reliable Messaging. Mike showed in his
WS Reliable Messaging and Session Support Part 2
what are the
problems with this approach and we now
conclude with a third part where we have tried to fix some of these
problems .
Sessions are unique
ids used to identify a client. They would help
maintain state for each client.
In this sample you will see how
sessions can be supported with WS Reliable Messaging (WS RM) .
WS
RM is one of the
enterprise features in Project
which is Sun's
interoperability project with Microsoft's
Windows Communication
Foundation (WCF).
The following snippets of code show how the JAX-WS Endpoint
implementation which is RM enabled
supports sessions .
This is the
wsdl which shows RM is enabled in the endpoint by the presence of
Policy Assertions.
Here is endpoint implementation class
@WebService(endpointInterface="rmdemo.server.RMDemo")
public class RMDemoImpl {
....
}As shown in part 1 JAX-WS uses annotations defined by Common
Annotations for the Java
Platform (JSR 250),
to inject the Web ServiceContext and declare lifecycle methods. Web
ServiceContext holds the
context
information pertaining to a request being served. With JAX-WS Web
Service all you need to do is
mark a field or method
with @Resource. From the WebServiceContext,
pertaining
to the the current request can be accessed.
@Resource
private javax.xml.ws.WebServiceContext context;
As mentioned above WebServiceContext exposes the
for the request being served when this method is called .
The session
is obtained from the MessageContext using a jax-ws property
"com.sun.xml.ws.session"
private Hashtable getSession() {
return (Hashtable)context.getMessageContext()
.get("com.sun.xml.ws.session");
}
The following getter method returns the String associated
with each request .
Correspondingly the setter method
stores the Strings for each session in the
HashTable respectively.
private String getSessionData() {
Hashtable sess = getSession();
String ret = (String)sess.get("request_record");
return ret != null ? ret : "";
}
private void setSessionData(String data) {
Hashtable session = getSession();
session.put("request_record", data);
}These addString method and getResult method are exposed by our RM
endpoint and are same as Part 1 .
The method addString takes a
String
as entered by a user and adds it to the Strings stored in the session
data for that session.
The getResult will return all the strings entered by the user during
that session.
setSessionData(getSessionData() + " " + s);
Full source code for the
is here.
Advantages
Here the Session is created every time a new CreateSequence request is
received and gets terminated everytime there is a
TerminateSequence
request. This way the resource management issue as mentioned by Mike is
addressed.
Client Code
is the source code for the client. The client enters various
input Strings and finally hits carriage
return to terminate the client application and all the Strings received
so far for that client will be returned by
the
server.
Sample will be bundled in the wsit workspace and this is
the
to run the samples.
WSIT
website
Check this website for latest source code,
samples,documentation
server
Netbeans IDE Module:
All WSIT technologies available today can be
configured visuall
using this Netbeans module.
href="http://specs.xmlsoap.org/ws/2005/02/rm/ws-reliablemessaging.pdf">WS-ReliableMessaging
specification
Session With JAX-WS
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