cvr::object Class Reference

Base class for most objects in the CVR-Lib. More...

#include <cvrObject.h>

Inheritance diagram for cvr::object:

List of all members.

Public Member Functions

object ()

virtual ~object ()

virtual const std::string & name () const =0

virtual object * clone () const =0

virtual object * newInstance () const =0

Protected Member Functions

virtual std::string buildName () const

Detailed Description

Base class for most objects in the CVR-Lib.

All classes inherited from cvr::object have three important methods:

name() returns a const reference to a std::string with the name of the class (see cvr::className for more information).
clone() a new instance of the object is created and a pointer to this instance is returned. The internal state of the instance is a copy of the original.
newInstance() a new instance of the same object class is created using the default constructor.

Note that there are many classes in the library which are not inherited from this class, but most complex objects are (functors, classifiers, containers, etc.). The simplest decision rule to decide if a class should inherit from cvr::object is the question, should the objects be "clonable"?

The CVR-Libmakes extensive use of the C++ feature which allows to change the type of overloaded virtual methods. This feature was not supported in old compilers like Visual C++ 6.0 or early GCC compilers, and is a reason why they are not supported.

In all inherited classes the method name() has to be overloaded. The content of those methods can be easily implemented with the macro _CVR_RETURN_CLASS_NAME. For example:

 const std::string& yourClass::name() {
   _CVR_RETURN_CLASS_NAME
 }

Constructor & Destructor Documentation

cvr::object::object ( )

Default constructor.

Initializes the complete library

virtual cvr::object::~object ( ) [virtual]

Destructor.

Member Function Documentation

virtual std::string cvr::object::buildName ( ) const [protected, virtual]

Build for the name of the current class.

Note that the same string is returned by the method name(), but in a MUCH more efficient way. This method has to demangle the output of typeid().name() which takes some time. The method cvr::object::name() calls the buildName() only once and stores the result in a static variable which is just returned in successive calls, taking much less time.

You should NEVER EVER use this method directly, use name() instead.

virtual object* cvr::object::clone ( ) const [pure virtual]

Clone method.

You can create an identical instance of the current cvr::object using this method.

The difference with the method newInstance() is that here the internal state is kept in the copies while newInstance() creates always an object with the default parameters.

Usually, the implementation of the overloaded method in an inherited class will make use of the copy constructor:

   yourClass* yourClass::clone() const {
     return new yourClass(*this);
   }

Returns:: a pointer to the new instance.

Warning:: You have to take care of the memory management of the returned instance and delete it when you don't need it any more. Otherwise you will have some memory leaks.

virtual const std::string& cvr::object::name ( ) const [pure virtual]

Return the fully qualified name of this class.

Each class has to overload this function and return its name. The returned string is system-independent. It uses cvr::className to generate the class name but uses an internal singleton to avoid building the class name more than once.

Note that the factories of the CVR-Libcan use the name given by name() to create instances of a class at runtime (see cvr::factory).

This method must be overloaded in all derived classes. You can use the macro _CVR_RETURN_CLASS_NAME to produce the desired behaviour. For example:

 const std::string& yourClass::name() {
   _CVR_RETURN_CLASS_NAME
 }

The returned strings do not have any spaces, even if the resulting name is not anymore C++ compliant. This rule is easier to remember as a rule to specify when the spaces are required! For example, a type "cvr::list< cvr::point<double> >" will produce the name "cvr::list<cvr::point<double>>". Remember that the space between the last two angle brackets "> >" is in C++ necessary to avoid syntactic confusion with the operator ">>".

Returns:: The fully qualified name of this class without any spaces.

This method replaces the old method getTypeName() in older versions of the CVR-Lib. Since the results are totally different, a new name has been chosen to make this difference clear!

virtual object* cvr::object::newInstance ( ) const [pure virtual]

New instance method.

You can create a new instance of the current object, using the default constructor.

Note that the difference with the clone() method is that the latter also copies the internal state of the object, while this method just uses the default constructor.

Usually, the implementation of the overloaded method in an inherited class will make use of the default constructor:

   yourClass* yourClass::newInstance() const {
     return new yourClass();
   }

Returns:: a pointer to the new instance.

Warning:: You have to take care of the memory management of the returned instance and delete it when you don't need it any more. Otherwise you will have some memory leaks.

The documentation for this class was generated from the following file:

cvrObject.h


Public Member Functions
	object ()
virtual	~object ()
virtual const std::string &	name () const =0
virtual object *	clone () const =0
virtual object *	newInstance () const =0
Protected Member Functions
virtual std::string	buildName () const