Nullable< T > Class Template Reference

#include <nullable.h>

List of all members.

Public Member Functions
	Nullable ()
	Nullable (const NullValue &)
	Nullable (const T &t)
	Nullable (const Nullable< T > &t)
Nullable< T > &	operator= (const T &t)
Nullable< T > &	operator= (const Nullable< T > &t)
bool	isNull () const
	operator T () const
T &	value ()
T	value (const T &defaultval=T()) const
bool	operator== (const T &t) const
bool	operator!= (const T &t) const
bool	operator== (const Nullable< T > &t) const
bool	operator!= (const Nullable< T > &t) const
bool	operator== (const NullValue &) const
	compares the Nullable with the special null value
bool	operator!= (const NullValue &) const
	compares the Nullable with the special null value

---

Detailed Description

template<class T>
class Nullable< T >

wrapper around scalar values that makes them NULL-able, i.e. the virtual value NULL is added to the range of the wrapped value; wrapped classes must have a default constructor and =, == and != operators

---

Constructor & Destructor Documentation

template<class T>

Nullable< T >::Nullable

(

)

[inline]

creates a NULL value

template<class T>

Nullable< T >::Nullable

(

const NullValue &

)

[inline]

creates a NULL value

template<class T>

Nullable< T >::Nullable

(

const T &

t

)

[inline]

creates a wrapped non-NULL value that is equivalent to the original

template<class T>

Nullable< T >::Nullable

(

const Nullable< T > &

t

)

[inline]

copies a nullable value

---

Member Function Documentation

template<class T>

bool Nullable< T >::isNull

(

)

const [inline]

returns whether this instance is NULL

template<class T>

Nullable< T >::operator T

(

)

const [inline]

converts this nullable to the original wrapped class - uses the default constructor if it is NULL

template<class T>

bool Nullable< T >::operator!=

(

const T &

t

)

const [inline]

compares this instance with a value of the original class, NULL is different from ANY instance of the original class

template<class T>

bool Nullable< T >::operator!=

(

const Nullable< T > &

t

)

const [inline]

compares two nullable instances, if both are NULL it returns false

template<class T>

bool Nullable< T >::operator!=

(

const NullValue &

)

const [inline]

compares the Nullable with the special null value

template<class T>

Nullable<T>& Nullable< T >::operator=

(

const Nullable< T > &

t

)

[inline]

copies the given nullable value

template<class T>

Nullable<T>& Nullable< T >::operator=

(

const T &

t

)

[inline]

makes this instance non-NULL and equivalent to the given value

template<class T>

bool Nullable< T >::operator==

(

const Nullable< T > &

t

)

const [inline]

compares two nullable instances, if both are NULL it returns true

template<class T>

bool Nullable< T >::operator==

(

const NullValue &

)

const [inline]

compares the Nullable with the special null value

template<class T>

bool Nullable< T >::operator==

(

const T &

t

)

const [inline]

compares this instance with a value of the original class, NULL is different from ANY instance of the original class

template<class T>

T Nullable< T >::value

(

const T &

defaultval = T()

)

const [inline]

returns the original value, if it is currently NULL it returns the given default value, if no default is given an instance created with the default constructor is returned

template<class T>

T& Nullable< T >::value

(

)

[inline]

returns a reference to the wrapped value - the result is undefined if it us currently NULL

---

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

• include/nullable.h