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POSynchronous RPC Calls in GWT
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  1. POSynchronous RPC Calls in GWT
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    copied!<p>(That title alone should cause people to come out of the woodwork to bash me with clubs, but hear me out).</p> <p>I have a use case where I need to return a value from a asynchronous call. (I'm using GWT-Platform, but the concepts are the same.) I declared a final JavaScriptObject array, then assigned the value within the AsyncCallback. However, I need to return the value, and the method returns before the AsyncCallback completes. Therefore, I need to block somehow until the AsyncCallback completes. I need the returned value in another method, or I'd just do what I need to in onSuccess().</p> <p>I've tried loops, Timers, and a few other methods with no luck. Can anyone help?</p> <pre><code>@Override public JavaScriptObject doGetWhereAmIMarker(final double lng, final double lat) { final JavaScriptObject[] markerArray = new JavaScriptObject[1]; // ugly hack, I know dispatch.execute(new GetLocationDescriptionsAction(lng, lat), new AsyncCallback&lt;GetLocationDescriptionsResult&gt;() { @Override public void onFailure(Throwable caught) { caught.printStackTrace(); } @Override public void onSuccess(GetLocationDescriptionsResult result) { Map&lt;String, Location&gt; resultMap = result.getResult(); StringBuffer message = new StringBuffer(); for (String key : resultMap.keySet()) { message.append(key).append(": ").append(resultMap.get(key)).append("\n"); } Map tempMap = new HashMap(); tempMap.put("TITLE","Location Information"); tempMap.put("LAT", lat); tempMap.put("LNG", lng); tempMap.put("CONTENTS", message.toString()); JavaScriptObject marker = GoogleMapUtil.createMarker(tempMap); markerArray[0] = marker; if (markerArray[0] != null) { GWT.log("Marker Array Updated"); } } }); return markerArray[0]; } </code></pre> <p>UPDATE: As requested, here is the code that calls doGetWhereIAmMarker(). I've tried having a separate native method with the Google Map object (as a JavaScriptObject) as a parameter, but it appears that passing that object between native methods kills the ability to update said object.</p> <pre><code>public native void initMap(JavaScriptObject mapOptions, JavaScriptObject bounds, JavaScriptObject border, JsArray markerArray, Element e) /*-{ // create the map and fit it within the given bounds map = new $wnd.google.maps.Map(e, mapOptions); if (bounds != null) { map.fitBounds(bounds); } // set the polygon for the borders if (border != null) { border.setMap(map); } // set up the info windows if (markerArray != null &amp;&amp; markerArray.length &gt; 0) { var infoWindow = new $wnd.google.maps.InfoWindow({ content:"InfoWindow Content Goes Here" }); for (var i = 0; i &lt; markerArray.length; i++) { var marker = markerArray[i]; marker.setMap(map); $wnd.google.maps.event.addListener(marker, 'click', function() { infoWindow.setContent(marker.content); infoWindow.open(map, this); }); } } // need to reference the calling class inside the function(), so set a reference to "this" var that = this; $wnd.whereAmI=function(lng, lat) { that.@org.jason.mapmaker.client.view.MapmakerMapViewImpl::whereAmI(DD)(lng,lat); } $wnd.google.maps.event.addListener(map, 'click', function(event) { var lat = event.latLng.lat(); var lng = event.latLng.lng(); $wnd.whereAmI(lng, lat); }); }-*/; </code></pre>
 

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