Method for getting both feature id and data.

Having to call two methods to get complete feature information (id and data) is cumbersome.  The `getFeatureInfo` method returns an object with both feature id and data.

lib/OpenLayers/Control/UTFGrid.js

@@ -33,7 +33,7 @@
  * var control = new OpenLayers.Control.UTFGrid({
  *     layers: [world_utfgrid],
  *     handlerMode: 'move',
- *     callback: function(dataLookup) {
+ *     callback: function(infoLookup) {
  *         // do something with returned data
  *
  *     }
@@ -175,14 +175,14 @@ OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
         
         var layers = this.findLayers();
         if (layers.length > 0) {
-            var dataLookup = {};
+            var infoLookup = {};
             var layer, idx;
             for (var i=0, len=layers.length; i<len; i++) {
                 layer = layers[i];
                 idx = this.map.layers.indexOf(layer);
-                dataLookup[idx] = layer.getFeatureData(lonLat);
+                infoLookup[idx] = layer.getFeatureInfo(lonLat);
             }
-            this.callback(dataLookup); // perhaps pass tile, lonLat?
+            this.callback(infoLookup); // perhaps pass tile, lonLat?
         }
     },
 
@@ -192,12 +192,12 @@ OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
      *     includes data in one of the configured UTFGrid layers.
      *
      * Parameters:
-     * dataLookup - {Object} Keys of this object are layer indexes and can be
+     * infoLookup - {Object} Keys of this object are layer indexes and can be
      *     used to resolve a layer in the map.layers array.  The structure of
      *     the property values depend on the data included in the underlying
      *     UTFGrid and may be any valid JSON type.  
      */
-    callback: function(dataLookup) {
+    callback: function(infoLookup) {
         // to be provided in the constructor
     },
 

lib/OpenLayers/Layer/UTFGrid.js

@@ -237,22 +237,26 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
     },
     
     /**
-     * APIProperty: getFeatureData
-     * Get feature data from UTFGrid associated with a map location.
+     * APIProperty: getFeatureInfo
+     * Get details about a feature associated with a map location.  The object
+     *     returned will have id and data properties.  If the given location
+     *     doesn't correspond to a feature, null will be returned.
      *
      * Parameters:
      * location - {<OpenLayers.LonLat>} map location
      *
      * Returns:
-     * {Object} The UTFGrid data corresponding to the given map location.
+     * {Object} Object representing the feature id and UTFGrid data 
+     *     corresponding to the given map location.  Returns null if the given
+     *     location doesn't hit a feature.
      */
-    getFeatureData: function(location) {
-        var data;
-        var info = this.getTileInfo(location);
-        if (info.tile) {
-            data = info.tile.getFeatureData(info.i, info.j);
+    getFeatureInfo: function(location) {
+        var info = null;
+        var tileInfo = this.getTileInfo(location);
+        if (tileInfo.tile) {
+            info = tileInfo.tile.getFeatureInfo(tileInfo.i, tileInfo.j);
         }
-        return data;
+        return info;
     },
 
     /**
@@ -263,10 +267,11 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
      * location - {<OpenLayers.LonLat>} map location
      *
      * Returns:
-     * {Object} The feature identifier corresponding to the given map location.
+     * {String} The feature identifier corresponding to the given map location.
+     *     Returns null if the location doesn't hit a feature.
      */
     getFeatureId: function(location) {
-        var id;
+        var id = null;
         var info = this.getTileInfo(location);
         if (info.tile) {
             id = info.tile.getFeatureId(info.i, info.j);

lib/OpenLayers/Tile/UTFGrid.js

@@ -146,22 +146,29 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
     },
     
     /**
-     * Method: getFeatureData
-     * Get feature data associated with a pixel offset.
+     * Method: getFeatureInfo
+     * Get feature information associated with a pixel offset.  If the pixel
+     *     offset corresponds to a feature, the returned object will have id
+     *     and data properties.  Otherwise, null will be returned.
+     *     
      *
      * Parameters:
      * i - {Number} X-axis pixel offset (from top left of tile)
      * j - {Number} Y-axis pixel offset (from top left of tile)
      *
      * Returns:
-     * {Object} The UTFGrid data corresponding to the given pixel offset.
+     * {Object} Object with feature id and data properties corresponding to the 
+     *     given pixel offset.
      */
-    getFeatureData: function(i, j) {
-        var data;
+    getFeatureInfo: function(i, j) {
+        var info = null;
         if (this.json) {
-            data = this.json.data[this.getFeatureId(i, j)];
+            var id = this.getFeatureId(i, j);
+            if (id !== null) {
+                info = {id: id, data: this.json.data[id]};
+            }
         }
-        return data;
+        return info;
     },
     
     /**
@@ -174,16 +181,20 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
      *
      * Returns:
      * {Object} The feature identifier corresponding to the given pixel offset.
+     *     Returns null if pixel doesn't correspond to a feature.
      */
     getFeatureId: function(i, j) {
-        var id;
+        var id = null;
         if (this.json) {
             var resolution = this.utfgridResolution;
             var row = Math.floor(j / resolution);
             var col = Math.floor(i / resolution);
             var charCode = this.json.grid[row].charCodeAt(col);
             var index = this.indexFromCharCode(charCode);
-            id = this.json.keys[index];
+            var keys = this.json.keys;
+            if (!isNaN(index) && (index in keys)) {
+                id = keys[index];
+            }
         }
         return id;
     },