Gwt Request builder - how to return the response string

Question

I need to implement a function that calls a web service and return the response.

I tried

public String getFolderJson(String path) {  
           Stri         


        

Answer 1

GWT does not support synchronous Ajax, so you have to code your app using asynchronous pattern.

The low level object that GWT uses to perform the request is a XMLHttpRequest (except for old IE versions), and GWT always calls it's open() method with async set to true. So the only way to have synchronous ajax is maintaining your own modified version of XMLHttpRequest.java. But synchronous ajax is a bad idea, and even jQuery has deprecated this possibility.

So the normal way in gwt should be that your method returns void, and you passes an additional parameter with a callback to execute when the response is available.

public void getFolderJson(String path, Callback callback) {  
    RequestBuilder builder = new RequestBuilder(...);
    try {
      builder.sendRequest(null, new RequestCallback() {  
        @Override  
        public void onResponseReceived(Request request, Response response) {
          callback.onSuccess(response.getText());  
        }  
        @Override  
        public void onError(Request request, Throwable exception) {}
          callback.onFailure(exception.getMessage());  
        });
    } catch (RequestException e) {
        callback.onFailure(exception.getMessage());  
    }  
}

I'd rather gwtquery Promises syntax for this instead of request-builder one:

  Ajax.get("http://localhost/folder?sessionId=foo&path=bar")
    .done(new Function(){
      public void f() {
        String text = arguments(0);
      }
    });