JsonpRequestBuilder (GWT Javadoc)

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GWT 2.7.0

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com.google.gwt.jsonp.client
Class JsonpRequestBuilder

java.lang.Object
  com.google.gwt.jsonp.client.JsonpRequestBuilder

public class JsonpRequestBuilder
extends java.lang.Object
extends java.lang.Object

Class to send cross domain requests to an http server. The server will receive a request including a callback url parameter, which should be used to return the response as following:

<callback>(<json>);

where <callback> is the url parameter (see setCallbackParam(String)), and <json> is the response to the request in json format. This will result on the client to call the corresponding AsyncCallback.onSuccess(Object) method.

If needed, errors can be handled by a separate callback:

<failureCallback>(<error>);

where <error> is a string containing an error message. This will result on the client to call the corresponding AsyncCallback.onFailure(Throwable) method. See setFailureCallbackParam(String).

Example using JSON Google Calendar GData API:

 String url = "http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full" +
     "?alt=json-in-script";
 JsonpRequestBuilder jsonp = new JsonpRequestBuilder();
 jsonp.requestObject(url,
     new AsyncCallback<Feed>() {
       public void onFailure(Throwable throwable) {
         Log.severe("Error: " + throwable);
       }

       public void onSuccess(Feed feed) {
         JsArray<Entry> entries = feed.getEntries();
         for (int i = 0; i < entries.length(); i++) {
           Entry entry = entries.get(i);
           Log.info(entry.getTitle() +
                    " (" + entry.getWhere() + "): " +
                    entry.getStartTime() + " -> " +
                    entry.getEndTime());
         }
       }
     });

This example uses these overlay types:

 class Entry extends JavaScriptObject {
   protected Entry() {}

   public final native String getTitle() /*-{
     return this.title.$t;
   }-*/;

   public final native String getWhere() /*-{
     return this.gd$where[0].valueString;
   }-*/;

   public final native String getStartTime() /*-{
     return this.gd$when ? this.gd$when[0].startTime : null;
   }-*/;

   public final native String getEndTime() /*-{
     return this.gd$when ? this.gd$when[0].endTime : null;
   }-*/;
 }

 class Feed extends JavaScriptObject {
   protected Feed() {}

   public final native JsArray<Entry> getEntries() /*-{
     return this.feed.entry;
   }-*/;
 }

Constructor Summary
`JsonpRequestBuilder()`

Method Summary

java.lang.String getCallbackParam()
Returns the name of the callback url parameter to send to the server.

java.lang.String getFailureCallbackParam()
Returns the name of the failure callback url parameter to send to the server.

int getTimeout()
Returns the expected timeout (ms) for this request.

JsonpRequest<java.lang.Boolean> requestBoolean(java.lang.String url, AsyncCallback<java.lang.Boolean> callback)

JsonpRequest<java.lang.Double> requestDouble(java.lang.String url, AsyncCallback<java.lang.Double> callback)

JsonpRequest<java.lang.Integer> requestInteger(java.lang.String url, AsyncCallback<java.lang.Integer> callback)





<T extends JavaScriptObject> 


JsonpRequest<T>

requestObject(java.lang.String url,
              AsyncCallback<T> callback)

Sends a JSONP request and expects a JavaScript object as a result.

JsonpRequest<java.lang.String> requestString(java.lang.String url, AsyncCallback<java.lang.String> callback)

void send(java.lang.String url)
Sends a JSONP request and does not expect any results.

JsonpRequest<java.lang.Void> send(java.lang.String url, AsyncCallback<java.lang.Void> callback)
Sends a JSONP request, does not expect any result, but still allows to be notified when the request has been executed on the server.

void setCallbackParam(java.lang.String callbackParam)

void setFailureCallbackParam(java.lang.String failureCallbackParam)

void setPredeterminedId(java.lang.String id)

void setTimeout(int timeout)

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail