| Member Functions |
| addDependent() changed() removeDependent() |
#include <rw/model.h> (abstract base class)
This abstract base class has been designed to implement the "Model" leg of a Model-View-Controller architecture. A companion class, RWModelClient, supplies the "View" leg.
It maintains a list of dependent RWModelClient objects. When member function changed(void*) is called, the list of dependents will be traversed, calling updateFrom(RWModel*, void*) for each one, with itself as the first argument. Subclasses of RWModelClient should be prepared to accept such a call.
None
This is an incomplete and somewhat contrived example in that it does not completely define the classes involved. "Dial" is assumed to be a graphical representation of the internal settings of "Thermostat." The essential point is that there is a dependency relationship between the "Thermostat" and the "Dial": when the setting of the thermostat is changed, the dial must be notified so that it can update itself to reflect the new setting of the thermostat.
#include <rw/model.h>
class Dial : public RWModelClient {
public:
virtual void updateFrom(RWModel* m, void* d);
};
class Thermostat : public RWModel {
double setting;
public:
Thermostat( Dial* d )
{ addDependent(d); }
double temperature() const
{ return setting; }
void setTemperature(double t)
{ setting = t; changed(); }
};
void Dial::updateFrom(RWModel* m, void*) {
Thermostat* t = (Thermostat*)m;
double temp = t->temperature();
// Redraw graphic.
}
RWModel();
When called by the specializing class, sets up the internal ordered list of dependents.
void addDependent(RWModelClient* m);
Adds the object pointed to by m to the list of dependents of self.
void removeDependent(RWModelClient* m);
Removes the object pointed to by m from the list of dependents of self.
virtual void changed(void* d);
Traverse the internal list of dependents, calling member function updateFrom(RWModel*, void*) for each one, with self as the first argument and d as the second argument.