AttValPoi.h

Classes

AttributeValuePoi -- Templated class for storing a pointer to the value of an Attribute. (full description)

template <class T> class AttributeValuePoi : public AttributeValue<T>

Interface

Public Members

AttributeValuePoi(T* value, const Bool strict)

AttributeValuePoi(Vector<T> *value, const Bool strict)

AttributeValuePoi(const AttributeValuePoi<T> &other)

virtual ~AttributeValuePoi()

const AttributeValuePoi<T>& operator=(const AttributeValuePoi<T> &other)

virtual AttributeValueBase *clone() const

virtual void operator+=(const AttributeValueBase& other)

virtual void setValue(const T &value)

virtual void setValue(const Vector<T> &value)

virtual DataType getPointerType() const

virtual String className() const

Private Members

void updatePointerValue() const

const AttributeValuePoi<T>& myCast (const AttributeValueBase& other) const

AttributeValuePoi()

Description

Review Status

Date Reviewed:

yyyy/mm/dd

Programs:

Tests:

tAttribute

Prerequisite

AttributeValue

Etymology

"AttributeValuePoi" is a contraction of "Attribute Value" and "Pointer", and stores a pointer to the value of an Attribute.

Synopsis

An AttributeValuePoi differs from a AttributeValue in that instead of using its own variable to store the actual value like AttributeValue does, it stores a pointer to the variable used in the constructor. This means that the AttributeValuePoi is just an alias to this variable, and then the user can modify the value of an AttributeValuePoi without using its interface. Alternatively, and perhaps more importantly, the Attribute interface can be used to modify members of a class.

Example

A simple example will help illustrate the utility of the AttributeValuePoi class:

    Int varInt = 1;
    AttributeValuePoi<Int> intAtt(&varInt, False);
    
    Vector<Int> bla = intAtt.getValue();
    // bla(0) is 1;
    
    // This wil change also the AttributeValue:
    varInt = 2;
    bla = intAtt.getValue();
    // bla(0) is now 2
    
    intAtt.setValue(5);
    // now also varInt == 5

Motivation

The motivation for this class is to be able to provide an Attribute interface for modifying private members of some classes. For example, this interface is used to control the linear coordinate system of the WorldCanvas.