Adding support for cloning rules and filters. r=ahocevar (closes #1919)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@9071 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Rule.js

@@ -101,10 +101,9 @@ OpenLayers.Rule = OpenLayers.Class({
      * {<OpenLayers.Rule>}
      */
     initialize: function(options) {
-        this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_");
         this.symbolizer = {};
-
         OpenLayers.Util.extend(this, options);
+        this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_");
     },
 
     /** 
@@ -178,6 +177,33 @@ OpenLayers.Rule = OpenLayers.Class({
         }
         return context;
     },
+    
+    /**
+     * APIMethod: clone
+     * Clones this rule.
+     * 
+     * Returns:
+     * {<OpenLayers.Rule>} Clone of this rule.
+     */
+    clone: function() {
+        var options = OpenLayers.Util.extend({}, this);
+        // clone symbolizer
+        options.symbolizer = {};
+        for(var key in this.symbolizer) {
+            value = this.symbolizer[key];
+            type = typeof value;
+            if(type === "object") {
+                options.symbolizer[key] = OpenLayers.Util.extend({}, value);
+            } else if(type === "string") {
+                options.symbolizer[key] = value;
+            }
+        }
+        // clone filter
+        options.filter = this.filter && this.filter.clone();
+        // clone context
+        options.context = this.context && OpenLayers.Util.extend({}, this.context);
+        return new OpenLayers.Rule(options);
+    },
         
     CLASS_NAME: "OpenLayers.Rule"
 });