code: function(feature) {
          var context = this.context;
          if (!context) {
              context = feature.attributes || feature.data;
          }
          if (typeof this.context == "function") {
              context = this.context(feature);
          }
          return context;
      }
docs: Method: getContext
  Gets the context for evaluating this rule
  
  Paramters:
  feature - {<OpenLayers.Feature>} feature to take the context from if
  none is specified.