- Object Interactions
- Object Interaction Scenario in IT Management
- Example of a Mediator
- Mediator Base Class
- Mediator Subclass
- Widget Class
- Two Widget Subclasses
- LspDirector Implementation
- Widget Class Implementation
- PathWidget Class Implementation
- Putting It All Together
- Conclusion
- Additional Reading
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Two Widget Subclasses
Listing 5 illustrates the PathWidget subclass derived from the Widget class.
Listing 5 PathWidget Subclass
class PathWidget : public Widget
{
public:
explicit PathWidget(ConnectionDirector*);
virtual ~PathWidget(void);
void CreateInitialPath(char*);
void getNewPath(void);
void ChangePath(char*);
private:
char* pathDetails;
};
We’re now moving into the application domain described in Figure 1! The PathWidget class stores its configuration data in the private data member pathDetails. This configuration data takes the form of a character string describing the path taken by an LSP in Figure 1.
){kind=link}
Three member functions allow for manipulation of the configuration data:
- CreateInitialPath() is called at construction time to provide an initial value for pathDetails.
- getNewPath() is used to retrieve a modified version of pathDetails.
- ChangePath() is used to change the value of pathDetails.
Listing 6 illustrates the QosWidget subclass.
Listing 6 QosWidget Subclass
class QosWidget : public Widget
{
public:
explicit QosWidget(ConnectionDirector*);
virtual ~QosWidget(void);
void CreateInitialQoS(char*);
void getNewQoS(void);
void ChangeQoSDetails(char*);
private:
char* QoSDetails;
};
The QosWidget subclass is very similar to the PathWidget subclass. In fact, they’re so similar that there’s a case for trying to move some of their content into the base class. I’ll leave this as an exercise for the reader! An example of this is the _director data member in Listing 4, which is used by the subclasses.
You’ve seen the interface files; now let’s look at some of the implementation code.