Give Layer.Vector a method getFeaturesByAttribute, p=marcjansen, r=me (closes #2979)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@10960 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Vector.js

@@ -876,6 +876,36 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
     getFeatureByFid: function(featureFid) {
         return this.getFeatureBy('fid', featureFid);
     },
+    
+    /**
+     * APIMethod: getFeaturesByAttribute
+     * Returns an array of features that have the given attribute key set to the
+     * given value. Comparison of attribute values takes care of datatypes, e.g.
+     * the string '1234' is not equal to the number 1234.
+     *
+     * Parameters:
+     * attrName - {String}
+     * attrValue - {Mixed}
+     *
+     * Returns:
+     * Array(<OpenLayers.Feature.Vector>) An array of features that have the 
+     * passed named attribute set to the given value.
+     */
+    getFeaturesByAttribute: function(attrName, attrValue) {
+        var i,
+            feature,    
+            len = this.features.length,
+            foundFeatures = [];
+        for(i = 0; i < len; i++) {            
+            feature = this.features[i];
+            if(feature && feature.attributes) {
+                if (feature.attributes[attrName] === attrValue) {
+                    foundFeatures.push(feature);
+                }
+            }
+        }
+        return foundFeatures;
+    },
 
     /**
      * Unselect the selected features