Observables Implementation

About

An implementation of an interface that declares an observable must implement the behaviour of the observable. The observable must be initiated, freed and invoked.

Implementation

To implement basic observable functionality an implementation must include a maxon::ObserverObjectClass object with MAXON_COMPONENT().

The observable declared with MAXON_OBSERVABLE() is available as a member variable with the defined name and a "_" prefix.

// This example shows an implementation of an interface.
// It implements also an observable that is invoked when the function Ping() is called.
class ObserveMeImpl : public maxon::Component<ObserveMeImpl, ObserveMeInterface>
{
// use ObserverObjectClass to implement basic observer functionality
MAXON_COMPONENT(NORMAL, maxon::ObserverObjectClass);
public:
// implement observable
MAXON_OBSERVABLE_IMPL(ObservablePing);
maxon::Result<void> InitComponent()
{
_count = 0;
// init observable
_ObservablePing.Init(self, maxon::Id("ObservablePing")) iferr_return;
return maxon::OK;
}
void FreeComponent()
{
// free observable
_ObservablePing.Free();
}
MAXON_METHOD void Ping()
{
// increment
++_count;
// notify subscribers
iferr (_ObservablePing.Notify(_count))
{
DiagnosticOutput("Observable error: @", err);
}
}
private:
maxon::Int32 _count;
};

The observable must be implemented using MAXON_OBSERVABLE_IMPL().

ObservableBaseInterface

Observables are based on maxon::ObservableBaseInterface:

Subscriber notification:

Observers are handled with:

Further Reading

maxon::ComponentWithBase
Definition: objectbase.h:2604
MAXON_COMPONENT
#define MAXON_COMPONENT(KIND,...)
Definition: objectbase.h:2166
maxon::OK
return OK
Definition: apibase.h:2546
maxon::Id
Definition: apibaseid.h:250
iferr_return
#define iferr_return
Definition: resultbase.h:1465
DiagnosticOutput
#define DiagnosticOutput(formatString,...)
Definition: debugdiagnostics.h:167
maxon::Result< void >
MAXON_METHOD
#define MAXON_METHOD
Definition: interfacebase.h:877
maxon::Int32
int32_t Int32
32 bit signed integer datatype.
Definition: apibase.h:174
iferr_scope
#define iferr_scope
Definition: resultbase.h:1374
SCULPTBRUSHMODE::NORMAL
@ NORMAL
Samples the surface as the user moves over it the SculptObject and returns a new hit point and normal...
iferr
#define iferr(...)
Definition: errorbase.h:380
MAXON_OBSERVABLE_IMPL
#define MAXON_OBSERVABLE_IMPL(NAME,...)
Definition: observable.h:255