StatusCodeException Vs. RuntimeException in GWT

Question

In my GWT app. I overrode RemoteServiceServlet to check if the session is valid right before the service method is being called. I am trying to throw a RuntimeException("expired session") from the server and I would like the client to catch this exception from the asynccallback onFailure...

In the client I would like to: Asynccallback:

@Override
    public void onFailure(Throwable caught) {
        final String message = caught.getMessage();

        if (!isNullOrEmptyString(message) && message.contains("expired session")) {
            com.google.gwt.user.client.Window.Location.reload();
        }

    }

However, in the client, the caught object is still a StatusCodeException and the message is still the default "...Exception in the server...". how can I override the exception at least the default message to compare if it was a session expired message I sent from the server?

thanks

Hi Gursel, Here's my code: -> Custom RemoteServiceServlet. I'm trying to "intercept" every method before it's invoked. I check the session and throw a RuntimeException if it's already expired. So basically, it is not the declared method that throws the exception but the custom RemoteServiceServlet. It still goes to the "onFailure" in the client async but the Throwable object is still of type "StatusCodeException" without the EXPIRED_SESSION_MSG message. Don;t know how to make this work. Thanks!

public class XRemoteServiceServlet extends RemoteServiceServlet {
    private final static String EXPIRED_SESSION_MSG = "ERROR: Application has expired session.";   
    @Override
    protected void onAfterRequestDeserialized(RPCRequest rpcRequest) {
        HttpServletRequest httpServletRequest = this.getThreadLocalRequest();
        HttpSession session = httpServletRequest.getSession(false);
        if (session != null) {
            final String sessionIdFromRequestHeader = getSessionIdFromHeader();
            if (!isNullOrEmptyString(sessionIdFromRequestHeader)) {
                final String sessionId = session.getId();

                if (!sessionId.equals(sessionIdFromRequestHeader)) {
                    throw new RuntimeException(EXPIRED_SESSION_MSG);
                }
            }

Gursel Koca · Accepted Answer · 2011-06-06 07:59:07Z

5

All RuntimeExceptions thrown by Server side of gwt application has been wrapped as StatusCodeException if you did not declare them at your remote method declaration.

EDIT :

After, Thomas Broyer comment, I have learned that all exceptions (checked or unchecked) that are declared at remote method declaration are propagated to gwt client. Therefore all you have to do is just declare your remote method such as :

public void myRemoteMethod() throws RuntimeException;

edited Jun 6, 2011 at 7:59

answered Jun 6, 2011 at 7:35

Gursel Koca

21.4k2 gold badges26 silver badges34 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Thomas Broyer Over a year ago

Not sure about that one but… can't you propagate RuntimeExceptions to the client if you have explicit throws declarations for them on your interface?

mark Over a year ago

I found this tutorial: roussev.org/2010/02/gwt-dynamic-exception-handling/...Looks like this fits my needs...I'm still testing though

Gursel Koca Over a year ago

could you post your synch and asynch remote interface code?. What I have said, has been tested and it is working.

mark Over a year ago

Hi Gursel..I posted the code...Please let me know if you have a solution for it? Thanks.

Gursel Koca Over a year ago

@mark, there is no easy way to accomplish what you want . I suggest you to check expired session at your remote methods, not at onAfterRequestDeserialized.

|

Kisor Biswal · Accepted Answer · 2013-01-28 14:09:28Z

0

The post looks too old, still here is the solution I have come up with. Override processCall(String payload) of RemoveServiceServlet, if the session is invalid execute the blow code else call super.processCall(payload).

//Pass the exception to Client
RPCRequest rpcRequest = RPC.decodeRequest(payload, this.getClass(), this);
onAfterRequestDeserialized(rpcRequest);
return RPC.encodeResponseForFailure(rpcRequest.getMethod(), new CustomException("Invalid Session!"),rpcRequest.getSerializationPolicy(), rpcRequest.getFlags());

All the GWT services are servlets so GWT serializes the custom exception and sends to client as string, we follow the same :)

edited Jan 28, 2013 at 14:09

answered Jan 28, 2013 at 14:00

Kisor Biswal

1531 gold badge2 silver badges10 bronze badges

Collectives™ on Stack Overflow

StatusCodeException Vs. RuntimeException in GWT

2 Answers 2

6 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related