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SubclassIdentifier

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Description

SubclassIdentifier acts like a pointer to an Identifier with the difference that you can only assign Identifiers of classes inheriting from a given baseclass.

SubclassIdentifier is a template. The template-argument defines the needed base-class of an assigned Identifier. You can only assign Identifiers representing a class which is derived from the given base-class (or the base-class itself). If you try to assign an Identifier that's not derived from the base-class, you get an error.

Usage

Assignment

You can assign an Identifier either through the constructor or by using the assignment operator=:

// SubClass isA BaseClass:
SubclassIdentifier<BaseClass> identifier = Class(SubClass);

Function calls

the operator→ is overloaded an returns the assigned Identifier. That way you can just call functions of the assigned Identifier by using →function():

SubclassIdentifier<BaseClass> identifier = Class(SubClass);
identifier->getName(); // returns "SubClass"

fabricate()

There are two possibilities to create an object out of a SubclassIdentifier. Either you just use the fabricate() function of the assigned Identifier through the overloaded operator→. Remember: This function returns a BaseObject* pointer:

// creates a SubClass, returns a BaseObject* pointer
identifier->fabricate();

Or you use the function of SubclassIdentifier, this time by using operator., which returns a BaseClass?* pointer (BaseClass? is the baseclass specified by the template argument):

// creates a SubClass, returns a BaseClass* pointer
identifier.fabricate();

Examples

The following examples use the class-tree below.

SubclassIdentifier<A1> myidentifier = Class(A1);         // This works
SubclassIdentifier<A1> myidentifier = Class(A1B1);       // This works
SubclassIdentifier<A1> myidentifier = Class(A1B1C1);     // This works
SubclassIdentifier<A1> myidentifier = Class(BaseObject); // This doesn't work
SubclassIdentifier<A1> myidentifier = Class(A3);         // This doesn't work


SubclassIdentifier<Interface1> myidentifier = Class(A3);     // This works
SubclassIdentifier<Interface1> myidentifier = Class(A2B2C1); // This works
SubclassIdentifier<A1> myidentifier = Class(A1B1);

myidentifier->isExactlyA(Class(A1));       // Returns false
myidentifier->isExactlyA(Class(A1B1));     // Returns true
(*myidentifier)->getName();                // Returns "A1B1"
myidentifier->getName();                   // Returns "A1B1"

A1* newobject = myidentifier.fabricate();  // Returns a new instance of A1B1, casted to A1

Last modified 9 years ago Last modified on Sep 29, 2008, 3:02:38 AM