add "refresh" event to Layer.Vector, r=tschaub (closes #1695)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7959 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Vector.js

@@ -69,11 +69,14 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
      *  - *afterfeaturemodified* Triggered when a feature is finished being modified.
      *      Listeners will receive an object with a *feature* property referencing 
      *      the modified feature.
+     *  - *refresh* Triggered when something wants a strategy to ask the protocol
+     *      for a new set of features.
      */
     EVENT_TYPES: ["beforefeatureadded", "featureadded", "featuresadded",
                   "beforefeatureremoved", "featureremoved", "featuresremoved",
                   "beforefeatureselected", "featureselected", "featureunselected", 
-                  "beforefeaturemodified", "featuremodified", "afterfeaturemodified"],
+                  "beforefeaturemodified", "featuremodified", "afterfeaturemodified",
+                  "refresh"],
 
     /**
      * APIProperty: isBaseLayer
@@ -265,6 +268,21 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
         OpenLayers.Layer.prototype.destroy.apply(this, arguments);  
     },
 
+    /**
+     * Method: refresh
+     * Ask the layer to request features again and redraw them.  Triggers
+     *     the refresh event if the layer is in range and visible.
+     *
+     * Parameters:
+     * obj - {Object} Optional object with properties for any listener of
+     *     the refresh event.
+     */
+    refresh: function(obj) {
+        if(this.inRange && this.visibility) {
+            this.events.triggerEvent("refresh", obj);
+        }
+    },
+
     /** 
      * Method: assignRenderer
      * Iterates through the available renderer implementations and selects