Changes between Version 8 and Version 9 of code/doc/ClassIdentifier

Timestamp:

Sep 29, 2008, 2:24:31 AM (16 years ago)

Author:

landauf

Comment:

—

code/doc/ClassIdentifier

@@ -17 +17 @@
 == Description ==
 
-The ClassIdentifier is a [wiki:template], inherited from [wiki:Identifier], containing all class-specific functions for the class represented by the [wiki:Identifier]. In fact this is only the [wiki:ObjectList].
+The !ClassIdentifier is a [wiki:template] and a [wiki:singleton], derived from [wiki:Identifier], with two important tasks:
+ * Doing some class-specific stuff
+ * Fast and easy link to the Identifier of a class
 
-The constructor of ClassIdentifier is private. Only [wiki:IdentifierDistributor] is allowed to create and distribute new instances. (In fact only '''one''' instance per [wiki:template]-class. This is '''very''' important.)
+== Uniqueness ==
+Specially the second point is of major importance: !ClassIdentifier is a singleton, meaning there's only one instance of !ClassIdentifier<T> for every T. This allows you to get the Identifier of any class by calling !ClassIdentifier<classname>::getIdentifier():
+{{{
+Identifier* identifier = ClassIdentifier<SomeClass>::getIdentifier();
+}}}
+This is in fact just what the Class(classname) macro in [wiki:CoreIncludes] does.
 
-You can't access the ClassIdentifier of a class directly. Use [wiki:ClassManager]<!ClassName>::getIdentifier() instead. A shorter version of this command is the macro Class(classname) (include [wiki:CoreIncludes CoreIncludes.h] to use it) that returns the ClassIdentifier of the given class.
-
-== The !ObjectList ==
-
-Every class that uses the !RegisterObject(classname) or !RegisterRootObject(interfacename) macro (see [wiki:CoreIncludes]) is represented by an [wiki:Identifier], that stores all objects of this class (and of all inherited classes) in a [wiki:ObjectList]. The object gets removed from the list if it gets deleted. This is handled by the destructor of [wiki:OrxonoxClass] and the [wiki:MetaObjectList].
-
-You can iterate through all objects in a [wiki:ObjectList] by using an [wiki:Iterator]. Read the related Wiki-page to get more information.
-
-== Example ==
-
-{{{
-#!cpp
-MyClass.h:
-
-class MyClass : public BaseObject
-{
-  MyClass();
-};
-
-}}}
-
-{{{
-#!cpp
-MyClass.cc:
-
-#include "CoreIncludes.h"
-#include "MyClass.h"
-
-MyClass::MyClass()
-{
-  RegisterObject(MyClass);
-}
-}}}
-
-{{{
-#!cpp
-SomeOtherFile.cc:
-
-#include "CoreIncludes.h"
-#include "MyClass.h"
-
-Identifier* myidentifier = Class(MyClass);
-std::cout << myidentifier->getName() << std::endl;
-
-/*
-returns:
-MyClass
-*/
-}}}
+To assure uniqueness even in different libraries, a !ClassIdentifier has to register in a map. If the Identifier for a specific class already exists, the second !ClassIdentifier will just refer to the first one.