JsonpRequestBuilder (Google Web Toolkit Javadoc)

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

public class JsonpRequestBuilder
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

Constructors
Constructor and Description

JsonpRequestBuilder()

Constructors
Constructor and Description
`JsonpRequestBuilder()`

Method Summary

Methods
Modifier and Type	Method and Description
`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
- JsonpRequestBuilder
```
public JsonpRequestBuilder()
```

Method Detail

getCallbackParam
```
public java.lang.String getCallbackParam()
```
Returns the name of the callback url parameter to send to the server. The default value is "callback".

getFailureCallbackParam
```
public java.lang.String getFailureCallbackParam()
```
Returns the name of the failure callback url parameter to send to the server. The default is null.

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

requestBoolean

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

requestDouble

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

requestInteger

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

requestObject

public <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. The caller can either use JSONObject to parse it, or use a JavaScript overlay class.

requestString

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

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

send

public 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.

setCallbackParam
```
public void setCallbackParam(java.lang.String callbackParam)
```
Parameters:
callbackParam - The name of the callback url parameter to send to the server. The default value is "callback".

setFailureCallbackParam
```
public void setFailureCallbackParam(java.lang.String failureCallbackParam)
```
Parameters:
failureCallbackParam - The name of the failure callback url parameter to send to the server. The default is null.

setPredeterminedId

public void setPredeterminedId(java.lang.String id)

setTimeout
```
public void setTimeout(int timeout)
```
Parameters:
timeout - The expected timeout (ms) for this request. The default is 10s.

Class JsonpRequestBuilder

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

JsonpRequestBuilder

Method Detail

getCallbackParam

getFailureCallbackParam

getTimeout

requestBoolean

requestDouble

requestInteger

requestObject

requestString

send

send

setCallbackParam

setFailureCallbackParam

setPredeterminedId

setTimeout