jem::WeakRef< T > Class Template Reference

Provides `safe' acces to a collectable object without preventing the deletion of that object. More...

#include <jem/base/WeakRef.h>

Public Member Functions
	WeakRef ()
	Constructs a WeakRef that does not point to any object. More...
	WeakRef (const Ref< T > &rhs)
	Creates a WeakRef that points to an existing object. More...
	WeakRef (const WeakRef &rhs)
	Creates a copy of another WeakRef. More...
WeakRef &	operator= (const WeakRef &rhs)
	Copies another WeakRef. More...
Ref< T >	get () const
	Returns the object this WeakRef is pointing to. More...
void	swap (WeakRef &rhs)
	Interchanges two WeakRef objects. More...

Related Functions
(Note that these are not member functions.)
template<class T >
void	swap (WeakRef< T > &lhs, WeakRef< T > &rhs)
	Interchanges two WeakRef objects. More...

Detailed Description

template<class T>
class jem::WeakRef< T >

Like the template class Ref, the class WeakRef acts as a pointer to a collectable object of type T. Unlike a Ref, however, a WeakRef does not prevent the deletion of a collectable object. This means that if a collectable object can be reached only through one or more WeakRef instances, the collectable object will eventually be deleted.

A WeakRef is safe in the sense that it will return a NIL Ref instance when the collectable object no longer exists.

See also

Ref.

Constructor & Destructor Documentation

template<class T>

jem::WeakRef< T >::WeakRef

(

)

Constructs a WeakRef that does not point to any object.

Postcondition

this->get() == NIL

template<class T>

jem::WeakRef< T >::WeakRef

(

const Ref< T > &

rhs

)

Creates a WeakRef that points to the same object as the Ref rhs.

Parameters

rhs	- a Ref object.

Postcondition

this->get() == rhs

template<class T>

jem::WeakRef< T >::WeakRef

(

const WeakRef< T > &

rhs

)

Creates a WeakRef that points to the same object as the WeakRef rhs.

Parameters

rhs	- the WeakRef to be copied.

Postcondition

this->get() == rhs.get()

Member Function Documentation

template<class T>

WeakRef& jem::WeakRef< T >::operator=

(

const WeakRef< T > &

rhs

)

Copies the WeakRef rhs to this WeakRef.

Parameters

rhs	- the WeakRef to be copied.

Returns

*this

Postcondition

this->get() == rhs.get()

template<class T>

Ref<T> jem::WeakRef< T >::get

(

)

const

Returns a Ref that is either NIL or that points to the collectable object this WeakRef is pointing to.

Returns

A Ref object pointing to the object this WeakRef is pointing to.

template<class T>

void jem::WeakRef< T >::swap

(

WeakRef< T > &

rhs

)

Interchanges two WeakRef objects. This function is equivalent with:

WeakRef<T> tmp( *this );

(*this) = rhs;
rhs     = tmp;

Parameters

rhs	- the WeakRef with which this WeakRef should be swapped.

Friends And Related Function Documentation

template<class T >

void swap ( WeakRef< T > &  lhs, WeakRef< T > &  rhs  )

related

Swaps two WeakRef objects. This function is equivalent with: lhs.swap( rhs ).

Parameters

lhs	- a WeakRef object.
rhs	- another WeakRef object.