Add 'loadstart' and 'loadend' events to some of our exciting layers like WFS, GML, GeoRSS, and Text. tests to back it up. (Closes #808)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@4252 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/GML.js

@@ -81,6 +81,7 @@ OpenLayers.Layer.GML = OpenLayers.Class(OpenLayers.Layer.Vector, {
         // loaded after the GML is paited.
         // See http://trac.openlayers.org/ticket/404
         if(this.visibility && !this.loaded){
+            this.events.triggerEvent("loadstart");
             this.loadGML();
         }
     },
@@ -113,6 +114,7 @@ OpenLayers.Layer.GML = OpenLayers.Class(OpenLayers.Layer.Vector, {
 
         var gml = this.format ? new this.format() : new OpenLayers.Format.GML();
         this.addFeatures(gml.read(doc));
+        this.events.triggerEvent("loadend");
     },
     
     /**
@@ -125,6 +127,7 @@ OpenLayers.Layer.GML = OpenLayers.Class(OpenLayers.Layer.Vector, {
      */
     requestFailure: function(request) {
         alert("Error in loading GML file "+this.url);
+        this.events.triggerEvent("loadend");
     },
 
     CLASS_NAME: "OpenLayers.Layer.GML"

lib/OpenLayers/Layer/GeoRSS.js

@@ -67,6 +67,7 @@ OpenLayers.Layer.GeoRSS = OpenLayers.Class(OpenLayers.Layer.Markers, {
         OpenLayers.Layer.Markers.prototype.initialize.apply(this, [name, options]);
         this.location = location;
         this.features = [];
+        this.events.triggerEvent("loadstart");
         OpenLayers.loadURL(location, null, this, this.parseData);
     },
 
@@ -209,6 +210,7 @@ OpenLayers.Layer.GeoRSS = OpenLayers.Class(OpenLayers.Layer.Markers, {
             marker.events.register('click', feature, this.markerClick);
             this.addMarker(marker);
         }
+        this.events.triggerEvent("loadend");
     },
     
     /**

lib/OpenLayers/Layer/Text.js

@@ -47,7 +47,14 @@ OpenLayers.Layer.Text = OpenLayers.Class(OpenLayers.Layer.Markers, {
         OpenLayers.Layer.Markers.prototype.initialize.apply(this, arguments);
         this.features = new Array();
         if (this.location != null) {
-            OpenLayers.loadURL(this.location, null, this, this.parseData);
+
+            var onFail = function(e) {
+                this.events.triggerEvent("loadend");
+            };
+
+            this.events.triggerEvent("loadstart");
+            OpenLayers.loadURL(this.location, null, 
+                               this, this.parseData, onFail);
         }
     },
 
@@ -155,6 +162,7 @@ OpenLayers.Layer.Text = OpenLayers.Class(OpenLayers.Layer.Markers, {
                 }
             }
         }
+        this.events.triggerEvent("loadend");
     },
     
     /**

lib/OpenLayers/Layer/WFS.js

@@ -22,6 +22,12 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
      */
     isBaseLayer: false,
     
+    /**
+     * Property: tile
+     * {<OpenLayers.Tile.WFS>}
+     */
+    tile: null,    
+    
     /**
      * APIProperty: ratio
      * {Float} the ratio of image/tile size to map size (this is the untiled
@@ -234,6 +240,7 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
             if (!this.tile) {
                 this.tile = new OpenLayers.Tile.WFS(this, pos, tileBounds, 
                                                      url, tileSize);
+                this.addTileMonitoringHooks(this.tile);
                 this.tile.draw();
             } else {
                 if (this.vectorMode) {
@@ -243,6 +250,7 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
                     this.clearMarkers();
                 }    
                 this.tile.destroy();
+                this.removeTileMonitoringHooks(this.tile);
                 
                 this.tile = null;
                 this.tile = new OpenLayers.Tile.WFS(this, pos, tileBounds, 
@@ -252,6 +260,50 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
         }
     },
 
+    /** 
+     * Method: addTileMonitoringHooks
+     * This function takes a tile as input and adds the appropriate hooks to 
+     *     the tile so that the layer can keep track of the loading tile
+     *     (making sure to check that the tile is always the layer's current
+     *     tile before taking any action).
+     * 
+     * Parameters: 
+     * tile - {<OpenLayers.Tile>}
+     */
+    addTileMonitoringHooks: function(tile) {
+        tile.onLoadStart = function() {
+            //if this is the the layer's current tile, then trigger 
+            // a 'loadstart'
+            if (this == this.layer.tile) {
+                this.layer.events.triggerEvent("loadstart");
+            }
+        };
+        tile.events.register("loadstart", tile, tile.onLoadStart);
+      
+        tile.onLoadEnd = function() {
+            //if this is the the layer's current tile, then trigger 
+            // a 'tileloaded' and 'loadend'
+            if (this == this.layer.tile) {
+                this.layer.events.triggerEvent("tileloaded");
+                this.layer.events.triggerEvent("loadend");
+            }
+        };
+        tile.events.register("loadend", tile, tile.onLoadEnd);
+    },
+    
+    /** 
+     * Method: removeTileMonitoringHooks
+     * This function takes a tile as input and removes the tile hooks 
+     *     that were added in addTileMonitoringHooks()
+     * 
+     * Parameters: 
+     * tile - {<OpenLayers.Tile>}
+     */
+    removeTileMonitoringHooks: function(tile) {
+        tile.events.unregister("loadstart", tile, tile.onLoadStart);
+        tile.events.unregister("loadend", tile, tile.onLoadEnd);
+    },
+
     /**
      * Method: onMapResize
      * Call the onMapResize method of the appropriate parent class.