java - Fake a GWT Synchronous RPC call

Question

First of all, I know that doing a synchronous call is "wrong", and know that "is not possible".

But, in a situation a lot complex (i dont know how to explain), i need to wait the response from server, I'am using the GWT-Platform command implementation for the GWT RPC calls.

I was looking for some kind of "hack" for doing this.

Thanks in advance.

Answer 1

Usually, by handling stuff in the onSuccess() function of your RPC request, you'll automatically "wait the response from server". So I assume you want to block all the code currently running? Since JavaScript is single-threaded that won't be easy, there is no sleep function that just halts the program.

But it might be that a hack using a timer does what you want:

    Timer checkRPCResponse = new Timer() {
        @Override
        public void run() {
            if (!serverResponseReceived) {
                this.schedule(100);
            } else {
                proceedWithProgram();
            }
        }
    };
    checkRPCResponse.schedule(100);

I haven't tried out if the this.schedule(100) works in the above example, but you get the idea, which is a check if the server has responded every 100 ms. Of course you have to set serverResponseReceived = true yourself in the onSuccess() function. Call the timer right after the RPC.