ActionScript 3.0 Design Patterns

190 | Chapter 5: Adapter Pattern

The Adapter Class

We now have a target interface. The next step is to figure out if an object or class

adapter is the most suitable option. Because the existing class is small with only two

public methods, we won’t get any benefits from using a class adapter. If there were

methods in the existing class that could be directly used by the client in the new con-

text, a class adapter would make sense. Therefore, the CarAdapter shown in

Example 5-11 will be implemented as an object adapter.

Example 5-10. ICar.as

package
{
public interface ICar
{
function start( ):void
function turnMoreToTheLeft( ):void
function turnMoreToTheRight( ):void
function goStraight( ):void
}
}

Figure 5-5. The interface showing keyboard input

Example 5-11. CarAdapter.as

package
{
public class CarAdapter implements ICar
{

private var legacyCar:LegacyCar;
private var nSteeringAngle:Number;

Ignition key

function start() :void

function goStraight() :void

Up arrow key

Left arrow key Right arrow key

function turnMoreToTheRight() :void

function turnMoreToTheLeft() :void