RWModel(3C++) RWModel(3C++)
NameRWModel - Rogue Wave library class
Synopsis
#include <rw/model.h>
(abstract base class)
Description
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.
Persistence
None
Example
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); }
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RWModel(3C++) RWModel(3C++)
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.
}
Public ConstructorRWModel();
When called by the specializing class, sets up the internal ordered list
of dependents.
Public Member Functions
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.
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