Adding Behavior to Non-Dynamic ActionScript 3 Classes

When working with ActionScript 3, you might encounter scenarios where you need to extend functionality of existing classes—especially those generated from WSDL—which are inherently non-dynamic. The challenge? You want to add new methods without altering the autogenerated code or relying on inheritance. In this blog post, we’ll explore how to effectively achieve this.

Understanding the Problem

Your aim is to add new methods to a class that is not dynamic and is generated from a WSDL. Given that your class is non-dynamic, you can’t directly extend it with traditional inheritance techniques. For instance, your initial idea was to do something like this:

FooClass.prototype.method = function():String
{
    return "Something";
}

However, since the class is non-dynamic, the above approach won’t work. You need to find an alternative way to dynamically add behavior, akin to C# 3’s Extension Methods but within the constraints of ActionScript 3.

The Solution: Using Prototype Access

Interestingly, you can still extend functionality using the prototype while working with a non-dynamic class in ActionScript 3. Here’s how you can do it:

Step-by-Step Guide

1. Define a New Method: Instead of attaching a method directly to the prototype, you can set it on your object dynamically using bracket notation.

2. Implement It: Utilize the bracket notation to call the method on an instance of your class. Here’s how to implement this:

   Replace:

   foo.method();
   

   With:

   foo["method"]();
   

3. Conclusion: By accessing the method via bracket notation, ActionScript 3 allows you to bypass some of the constraints of non-dynamic classes, thus enabling you to utilize new methods as needed.

Example Code

Here is a concise example, demonstrating this solution in practice:

// Assuming FooClass is defined and is a non-dynamic class
var foo:FooClass = new FooClass();
foo["method"] = function():String {
    return "Something";
};

trace(foo["method"]());  // Output: Something

Wrapping Up

In summary, while non-dynamic ActionScript 3 classes limit your ability to add methods through prototype inheritance, you can successfully implement behavior by accessing methods using bracket notation. This method works effectively without the need for altering the original code structure, keeping your generated classes intact.

This approach not only enhances your coding flexibility but also aligns with practices from other programming languages such as C#. Keep experimenting, and you will find many ways to extend functionality in ActionScript 3 without conventional limitations.