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The term Polymorphism describes multiple possible states for a single property. And for the computers geeks, programmers, coders in us describes it as “a mechanism allowing a given function to have many different specifications, depending on the type(s) to which it is applied”.

More aptly in the world of OOP, Polymorphism is extensively used in an Inheritance relationship. It may not be wrong to point out that Polymorphism in ActionScript 2.0 was not as clear as it should have been. With ActionScript 3.0, it is being clearly demarcated with the keyword Override.

Let us look at some simple sample codes

// Mammal Speech in AS3.0
package
{
	import flash.display.Sprite;
	import flash.util.trace;
	//
	public class MammalSpeech extends Sprite
	{
		public function MammalSpeech()
		{
			var mammals:Array = [new HumanBeing(), new Cat(), new Dog()];
			for each (var mammal:Object in mammals)
			{
				command(mammal);
			}
		}
		private function command(mammal:Mammal)
		{
			mammal.speak();
		}
	}    
	// Base class Mammal
	private class Mammal
	{
		public function speak()
		{
		}
	}     
	// following are derived classes
	private class Cat extends Mammal
	{
		//Override keyword used in derived compulsory to override the Base class
		public override function speak()
		{
			trace("meow!");
		}
	}
	private class Dog extends Mammal
	{
		public override function speak()
		{
			trace("woof!");
		}
	}
	private class HumanBeing extends Mammal
	{
		public override function speak()
		{
			trace("Hi I am santoshkumar spend a lot of time in programming");             }
		}
	}
}

For the above code class Mammal is a Base class(Super) and type of Mammals like HumanBeing, Dog, Cat are derived class(Sub). It is very clear from the fact that HumanBeing, Dogs, Cats etc speak in different ways. So all derived classes must override the Base class method speak. This was an attempt to make an easy implementation of Polymorphism in ActionScript 3.0.

This entry was posted on Sunday, January 1st, 2006 at 8:43 am and is filed under Flash. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.