Professional PHP Design Patterns

7.2. UML

This Unified Modified Language (UML) diagram details a class design using the Delegate Design Pattern (see Figure 7-1).

Figure 7-1. Figure 7-1

Looking at this figure, you'll note that:

• The base class MyObject is aware that it will be using objects based on the Delegate Design Pattern. It contains a private string delegateType and a private instance of MyDelegateObject, called internalDelegate.

• The setDelegateType() method receives a parameter named type. This is stored in the delegateType string.

• The createDelegateObject() method will create an instance of a delegate object named after the delegateType variable. It then stores the instance internally by assigning it to internalDelegate.

• The runDelegateAction() method is responsible for running the action() method of the internalDelegate object.

• MyDelegateObject contains the logic responsible for this particular action. The action() method is run by MyObject to accomplish the feature.