fix for #643. layer class can be safely doubled up now

git-svn-id: http://svn.openlayers.org/trunk/openlayers@3035 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -148,24 +148,23 @@ OpenLayers.Layer.prototype = {
      * @param {Object} options Hashtable of extra options to tag onto the layer
      */
     initialize: function(name, options) {
-        //store a copy of the custom options for later cloning
-        this.options = OpenLayers.Util.extend(new Object(), options);
 
-        //add options to layer
+        this.addOptions(options);
-        OpenLayers.Util.extend(this, this.options);
 
         this.name = name;
         
+        if (this.id == null) {
+
             this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_");
 
-        if (this.div == null) {
             this.div = OpenLayers.Util.createDiv();
             this.div.style.width = "100%";
             this.div.style.height = "100%";
             this.div.id = this.id;
-        }
 
-        this.events = new OpenLayers.Events(this, this.div, this.EVENT_TYPES);
+            this.events = new OpenLayers.Events(this, this.div, 
+                                                this.EVENT_TYPES);
+        }
     },
     
     /**
@@ -218,9 +217,12 @@ OpenLayers.Layer.prototype = {
      * @param {String} newName
      */
     setName: function(newName) {
+        if (newName != this.name) {
             this.name = newName;
-        if (this.map != null)
+            if (this.map != null) {
                 this.map.events.triggerEvent("changelayer");
+            }
+        }
     },    
     
    /**
@@ -228,6 +230,10 @@ OpenLayers.Layer.prototype = {
     */
     addOptions: function (newOptions) {
         
+        if (this.options == null) {
+            this.options = new Object();
+        }
+        
         // update our copy for clone
         OpenLayers.Util.extend(this.options, newOptions);
 
@@ -266,6 +272,8 @@ OpenLayers.Layer.prototype = {
      * @param {OpenLayers.Map} map
      */
     setMap: function(map) {
+        if (this.map == null) {
+        
             this.map = map;
             
             // grab some essential layer data from the map if it hasn't already
@@ -282,6 +290,7 @@ OpenLayers.Layer.prototype = {
             
             // deal with gutters
             this.setTileSize();
+        }
     },
   
     /**
@@ -380,10 +389,12 @@ OpenLayers.Layer.prototype = {
      * @param {Boolean} isBaseLayer 
      */
     setIsBaseLayer: function(isBaseLayer) {
+        if (isBaseLayer != this.isBaseLayer) {
             this.isBaseLayer = isBaseLayer;
             if (this.map != null) {
                 this.map.events.triggerEvent("changelayer");
             }
+        }
     },
 
   /********************************************************/
@@ -648,12 +659,14 @@ OpenLayers.Layer.prototype = {
      * @param {Float} opacity
      */
     setOpacity: function(opacity) {
+        if (opacity != this.opacity) {
             this.opacity = opacity;
             for(var i=0; i<this.div.childNodes.length; ++i) {
                 var element = this.div.childNodes[i].firstChild;
                 OpenLayers.Util.modifyDOMElement(element, null, null, null, 
                                                  null, null, null, opacity);
             }
+        }
     },
 
     /**