ActionScript 3.0 Design Patterns.pdf - VideoTutorials-bg.com

Example 2-5. CreatorA.as (continued)
}
}
}
Note that the doStuff( ) method in the Creator class is declared as public because we
need to allow clients to get to it from outside the package. In contrast, the
factoryMethod( ) is declared as protected. The protected attribute makes the method
visible only within the same class or derived classes. Finally, we can take a look at the
document class called Main, which is the client described in the class diagram shown
in Figure 2-2 that uses the creator to access products.
Clients
trace("Creating product 1");
return new Product1( ); // returns concrete product
Example 2-6. CreatorB.as
package example
{
public class CreatorB extends Creator
{
override protected function factoryMethod( ):IProduct
{
trace("Creating product 2");
return new Product2( ); // returns concrete product
}
}
}
The document class Main does not belong to a named package. Therefore, it must
import the packages that contain the classes it uses. The example package needs to be
imported, as it contains the creator classes. The document class Main is the client
described in the high-level model of the factory method pattern shown in Figure 2-1.
In Example 2-7, the document class calls a static method called run( ) in the static
Test class to run some tests.
Example 2-7. Main.as
package
{
import flash.display.Sprite;
import example.*;
/**
* Main Class
* @ purpose: Document class for movie
*/
public class Main extends Sprite
{
72 | Chapter 2: Factory Method Pattern