ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 12: Objects and Classes

are guaranteed to be unique. For example, to create a namespace for my classes I use

the following code (my site’s domain is moock.org):

if (_global.org = = undefined) {

_global.org = new Object( );

}

if (_global.org.moock = = undefined) {

_global.org.moock = new Object( );

}

This code appears in all my classes (each class has the responsibility of creating the

namespace if it doesn’t already exist.) Here’s a convenient function, AsSetupPackage( ),

that you can use to create a namespace for your own classes:

_global.AsSetupPackage = function (path) {

var a = path.split('.');

var o = _global;

for (var i = 0; i < a.length; i++) {

var name = a[i];

if (o[name] = = undefined) {

o[name] = new Object( );

}

o = o[name];

}

}

Within each class, you can use AsSetupPackage( ) to create the class’s namespace, as

follows:

AsSetupPackage("com.yourdomain");

For example, I use:

AsSetupPackage("org.moock");

The Multiple-Choice Quiz, OOP Style

Now that you understand the principles of OOP, let’s return to our multiple-choice

quiz example to see them in action. The source code for our OOP quiz is too long to

present here, but it can be downloaded from the Code Depot. The important part of

the application is its object design, listed next. Even without seeing the code in