Updating Ownership Relations
As illustrated in the following code, a relation data member behaves like a pointer when it is accessed, and, as such, it can be dereferenced. In addition, a relation can be modified by the assignment of a pointer or a smart pointer.
// ...
typedef IlsSmartPointer<Car> CarP;
// ...
class Person:
public IlsObject
{
public:
IlsOwns<Person,Car> car;
Person();
};
CarP AssignNewCarAndRepaint(Person& p, CarP newCar){
p.car=newCar; // assignment of a new car
p.car->rePaint(); // apply rePaint function to the car
return p.car; // the relation can convert to a smart pointer
}
Two main rules govern the updating of an ownership relation:
By default, when an ownership relation is broken, if the target of this relation is also the target of a use relation, then the use relations are also severed.
Figure 2.2 Updating an Ownership Relation
If the relation is assigned a new target which is already the target of another ownership relation, the exception
IlsAlreadyInserted is thrown.
Version 5.8
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