Delving More Deeply into the Decorator Pattern

Up to now, we’ve used a single string variable with a single getter method for the basic abstract component class. However, like any other class, this basic structure can accommodate more than a single variable or function. Example 4-17 shows three variables and getter functions. Save the script asComponent.as.

Example 4-17. Component.as

package
{
   //Abstract class
   public class Component
   {
      protected var soul:String="All that is inside a spirit";
      protected var goodness:Number;
      protected var vice:Number;

      public function getSoul():String
      {
         return soul;
      }
      public function good():Number
      {
         return goodness;
      }
      public function evil():Number
      {
         return vice;
      }
   }
}

Like the previous examples, we begin with a string property,soul. (It’s assigned a string literal, but that’s really not necessary because it’s an abstract class and will never be seen or used—just a clarification.) Next, two numeric properties are defined,goodnessandvice. These two properties will collect all the accumulated good and evil in a soul.

Next, three getter functions are supplied to get the values of the string and two numeric variables. Now the abstract component class is all set to go.