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Using Concrete Decorator Classes

In this fifth part of a six-part series on the decorator pattern, we create a whimsical example involving good and evil to show you concrete decorators in action. This article is excerpted from chapter four of ActionScript 3.0 Design Patterns Object Oriented Programming Techniques, written by William B. Sanders and Chandima Cumaranatunge (O'Reilly, 2007 ISBN: 0596528469). Copyright © 2007 O'Reilly Media, Inc. All rights reserved. Used with permission from the publisher. Available from booksellers or direct from O'Reilly Media.

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By: O'Reilly Media

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December 24, 2008

TABLE OF CONTENTS:

· Using Concrete Decorator Classes
· Deadly sins
· Implementing the Good and Evil Decorator
· Charting souls

package
{
   public class Rage extends Decorator
   {
      private var components:Component;
      public function Rage(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Rage";
      }
      override public function good():Number
      {
         return -9 + components.good();
      }
      override public function evil():Number
      {
         return 8 + components.evil();
      }
   }
}

Example 4-30. Malice.as

package
{
   public class Malice extends Decorator
   {
      private var components:Component;
      public function Malice(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Malice";
      }
      override public function good():Number
      {
         return -14 + components.good();
      }
      override public function evil():Number
      {
         return 12 + components.evil();
      }
   }
}

Example 4-31. Prejudice.as

package
{
   public class Prejudice extends Decorator
   {
      private var components:Component;
      public function Prejudice(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Prejudice";
      }
      override public function good():Number
      {
         return -10 + components.good();
      }
      override public function evil():Number
      {
         return 15 + components.evil();
      }
   }
}

Example 4-32. Obfuscation.as

package
{
   public class Obsfuscation extends Decorator
   {
      private var components:Component;
      public function Obsfuscation(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Obsfuscation";
      }
      override public function good():Number
      {
         return -12 + components.good();
      }
      override public function evil():Number
      {
         return 7 + components.evil();
      }
   }
}

Example 4-33. Dogmatisms.as

package
{
   public class Dogmatisms extends Decorator
   {
      private var components:Component;
      public function Dogmatisms(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Dogmatisms";
      }
      override public function good():Number
      {
         return -12 + components.good();
      }
      override public function evil():Number
      {
         return 15 + components.evil();
      }
   }
}

Example 4-34. Arrogance.as

package
{
   public class Arrogance extends Decorator
   {
      private var components:Component;
      public function Arrogance(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Arrogance";
      }
      override public function good():Number
      {
         return -5 + components.good();
      }
      override public function evil():Number
      {
         return 5 + components.evil();
      }
   }
}

Example 4-35. Indifference.as

package
{
   public class Indifference extends Decorator
   {
      private var components:Component;
      public function Indifference(components:Component)
      {
         this.components=components;
      }
      override public function getSoul():String
      {
         return components.getSoul() + "|Indifference";
      }
      override public function good():Number
      {
         return -9 + components.good();
      }
      override public function evil():Number
      {
         return 10 + components.evil();
      }
   }
}

At this point you can add your own concrete decorators. Use the same format as the others. You can also add additional concrete components. So instead of just Dick and Jane, you can add others you’d like to decorate with good and evil.

Next: Implementing the Good and Evil Decorator >>