--- a/labs/openlayers/lib/OpenLayers/Rule.js
+++ b/labs/openlayers/lib/OpenLayers/Rule.js
@@ -1,1 +1,240 @@
-
+/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for 
+ * full list of contributors). Published under the Clear BSD license.  
+ * See http://svn.openlayers.org/trunk/openlayers/license.txt for the
+ * full text of the license. */
+
+
+/**
+ * @requires OpenLayers/Util.js
+ * @requires OpenLayers/Style.js
+ * @requires OpenLayers/Symbolizer/Point.js
+ * @requires OpenLayers/Symbolizer/Line.js
+ * @requires OpenLayers/Symbolizer/Polygon.js
+ * @requires OpenLayers/Symbolizer/Text.js
+ * @requires OpenLayers/Symbolizer/Raster.js
+ */
+
+/**
+ * Class: OpenLayers.Rule
+ * This class represents an SLD Rule, as being used for rule-based SLD styling.
+ */
+OpenLayers.Rule = OpenLayers.Class({
+    
+    /**
+     * Property: id
+     * {String} A unique id for this session.
+     */
+    id: null,
+    
+    /**
+     * APIProperty: name
+     * {String} name of this rule
+     */
+    name: null,
+    
+    /**
+     * Property: title
+     * {String} Title of this rule (set if included in SLD)
+     */
+    title: null,
+    
+    /**
+     * Property: description
+     * {String} Description of this rule (set if abstract is included in SLD)
+     */
+    description: null,
+
+    /**
+     * Property: context
+     * {Object} An optional object with properties that the rule should be
+     * evaluated against. If no context is specified, feature.attributes will
+     * be used.
+     */
+    context: null,
+    
+    /**
+     * Property: filter
+     * {<OpenLayers.Filter>} Optional filter for the rule.
+     */
+    filter: null,
+
+    /**
+     * Property: elseFilter
+     * {Boolean} Determines whether this rule is only to be applied only if
+     * no other rules match (ElseFilter according to the SLD specification). 
+     * Default is false.  For instances of OpenLayers.Rule, if elseFilter is
+     * false, the rule will always apply.  For subclasses, the else property is 
+     * ignored.
+     */
+    elseFilter: false,
+    
+    /**
+     * Property: symbolizer
+     * {Object} Symbolizer or hash of symbolizers for this rule. If hash of
+     * symbolizers, keys are one or more of ["Point", "Line", "Polygon"]. The
+     * latter if useful if it is required to style e.g. vertices of a line
+     * with a point symbolizer. Note, however, that this is not implemented
+     * yet in OpenLayers, but it is the way how symbolizers are defined in
+     * SLD.
+     */
+    symbolizer: null,
+    
+    /**
+     * Property: symbolizers
+     * {Array} Collection of symbolizers associated with this rule.  If 
+     *     provided at construction, the symbolizers array has precedence
+     *     over the deprecated symbolizer property.  Note that multiple 
+     *     symbolizers are not currently supported by the vector renderers.
+     *     Rules with multiple symbolizers are currently only useful for
+     *     maintaining elements in an SLD document.
+     */
+    symbolizers: null,
+    
+    /**
+     * APIProperty: minScaleDenominator
+     * {Number} or {String} minimum scale at which to draw the feature.
+     * In the case of a String, this can be a combination of text and
+     * propertyNames in the form "literal ${propertyName}"
+     */
+    minScaleDenominator: null,
+
+    /**
+     * APIProperty: maxScaleDenominator
+     * {Number} or {String} maximum scale at which to draw the feature.
+     * In the case of a String, this can be a combination of text and
+     * propertyNames in the form "literal ${propertyName}"
+     */
+    maxScaleDenominator: null,
+    
+    /** 
+     * Constructor: OpenLayers.Rule
+     * Creates a Rule.
+     *
+     * Parameters:
+     * options - {Object} An optional object with properties to set on the
+     *           rule
+     * 
+     * Returns:
+     * {<OpenLayers.Rule>}
+     */
+    initialize: function(options) {
+        this.symbolizer = {};
+        OpenLayers.Util.extend(this, options);
+        if (this.symbolizers) {
+            delete this.symbolizer;
+        }
+        this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_");
+    },
+
+    /** 
+     * APIMethod: destroy
+     * nullify references to prevent circular references and memory leaks
+     */
+    destroy: function() {
+        for (var i in this.symbolizer) {
+            this.symbolizer[i] = null;
+        }
+        this.symbolizer = null;
+        delete this.symbolizers;
+    },
+    
+    /**
+     * APIMethod: evaluate
+     * evaluates this rule for a specific feature
+     * 
+     * Parameters:
+     * feature - {<OpenLayers.Feature>} feature to apply the rule to.
+     * 
+     * Returns:
+     * {Boolean} true if the rule applies, false if it does not.
+     * This rule is the default rule and always returns true.
+     */
+    evaluate: function(feature) {
+        var context = this.getContext(feature);
+        var applies = true;
+
+        if (this.minScaleDenominator || this.maxScaleDenominator) {
+            var scale = feature.layer.map.getScale();
+        }
+        
+        // check if within minScale/maxScale bounds
+        if (this.minScaleDenominator) {
+            applies = scale >= OpenLayers.Style.createLiteral(
+                    this.minScaleDenominator, context);
+        }
+        if (applies && this.maxScaleDenominator) {
+            applies = scale < OpenLayers.Style.createLiteral(
+                    this.maxScaleDenominator, context);
+        }
+        
+        // check if optional filter applies
+        if(applies && this.filter) {
+            // feature id filters get the feature, others get the context
+            if(this.filter.CLASS_NAME == "OpenLayers.Filter.FeatureId") {
+                applies = this.filter.evaluate(feature);
+            } else {
+                applies = this.filter.evaluate(context);
+            }
+        }
+
+        return applies;
+    },
+    
+    /**
+     * Method: getContext
+     * Gets the context for evaluating this rule
+     * 
+     * Paramters:
+     * feature - {<OpenLayers.Feature>} feature to take the context from if
+     *           none is specified.
+     */
+    getContext: function(feature) {
+        var context = this.context;
+        if (!context) {
+            context = feature.attributes || feature.data;
+        }
+        if (typeof this.context == "function") {
+            context = this.context(feature);
+        }
+        return context;
+    },
+    
+    /**
+     * APIMethod: clone
+     * Clones this rule.
+     * 
+     * Returns:
+     * {<OpenLayers.Rule>} Clone of this rule.
+     */
+    clone: function() {
+        var options = OpenLayers.Util.extend({}, this);
+        if (this.symbolizers) {
+            // clone symbolizers
+            var len = this.symbolizers.length;
+            options.symbolizers = new Array(len);
+            for (var i=0; i<len; ++i) {
+                options.symbolizers[i] = this.symbolizers[i].clone();
+            }
+        } else {
+            // clone symbolizer
+            options.symbolizer = {};
+            var value, type;
+            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"
+});