add changelayer event to mergeNewParams function, r=bartvde (closes #2179)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@9618 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/HTTPRequest.js

@@ -121,7 +121,14 @@ OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, {
      */
     mergeNewParams:function(newParams) {
         this.params = OpenLayers.Util.extend(this.params, newParams);
-        return this.redraw();
+        var ret = this.redraw();
+        if(this.map != null) {
+            this.map.events.triggerEvent("changelayer", {
+                layer: this,
+                property: "params"
+            });
+        }
+        return ret;
     },
 
     /**

lib/OpenLayers/Map.js

@@ -62,11 +62,12 @@ OpenLayers.Map = OpenLayers.Class({
      *      object will include a *layer* property that references the removed
      *      layer.
      *  - *changelayer* triggered after a layer name change, order change,
-     *      opacity change or visibility change (due to resolution thresholds).
+     *      opacity change, params change or visibility change
-     *      Listeners will receive an event object with *layer* and *property*
+     *      (due to resolution thresholds). Listeners will receive an event
-     *      properties.  The *layer* property will be a reference to the
+     *      object with *layer* and *property* properties. The *layer*
-     *      changed layer.  The *property* property will be a key to the
+     *      property will be a reference to the changed layer. 
-     *      changed property (name, order, opacity or visibility).
+     *      The *property* property will be a key to the
+     *      changed property (name, order, opacity, params or visibility).
      *  - *movestart* triggered after the start of a drag, pan, or zoom
      *  - *move* triggered after each drag, pan, or zoom
      *  - *moveend* triggered after a drag, pan, or zoom completes

tests/Layer/HTTPRequest.html

@@ -65,9 +65,19 @@
     }
 
     function test_Layer_HTTPRequest_mergeNewParams (t) {
-        t.plan( 4 );
+        t.plan( 8 );
 
+        var map = new OpenLayers.Map('map');
         layer = new OpenLayers.Layer.HTTPRequest(name, url, params, options);
+        map.addLayer(layer);
+
+        var scope = {some: "scope"}, log = [];
+        map.events.on({
+            changelayer: function(e) {
+                log.push({layer: e.layer, property: e.property, scope: this});
+            },
+            scope: scope
+        });
         
         var newParams = { layers: 'sooper', 
                           chickpeas: 'image/png'};
@@ -76,6 +86,10 @@
         
         t.eq( layer.params.layers, "sooper", "mergeNewParams() overwrites well");
         t.eq( layer.params.chickpeas, "image/png", "mergeNewParams() adds well");
+        t.eq( log.length, 1, "mergeNewParams() triggers changelayer once");
+        t.ok( log[0].layer == layer, "mergeNewParams() passes changelayer listener the expected layer");
+        t.ok( log[0].property == "params", "mergeNewParams() passes changelayer listener the property \"params\"");
+        t.eq( log[0].scope, scope, "mergeNewParams() executes changelayer listener with expected scope");
 
         newParams.chickpeas = 151;
 
@@ -85,8 +99,6 @@
             t.ok(true, "layer.mergeNewParams calls layer.redraw");
         }
         layer.mergeNewParams();
-
-
     }
 
     function test_Layer_HTTPRequest_getFullRequestString (t) {