OpenLayers.Rule class

When you want to be very specific about the types of styles that get applied to feature objects, the best way to do it is by using the Rule class. When you create a rule object, you specify a Filter object, a symbolizer to apply to the feature if the rule matches, and an optional name property which specifies an arbitrary name for the rule.

Rule objects are applied to style objects, and you can have virtually as many rules on a style object as you want. The syntax for creating a rule object, as mentioned previously, is:

var my_rule = new OpenLayers.Rule({
  filter: new OpenLayers.Filter({}),
  symbolizer: { key:values }
});
style_object.addRules([my_rule]);

As we saw in the previous example, it's not too hard to create and apply multiple rules to a style object. We only used a single filter for each rule object in the previous example, but OpenLayers makes it easy to specify multiple filters to give you even more control over your feature styles.

Rules are used in accordance...