Observes Environment variables. More...

#include <geogram/basic/environment.h>

Public Member Functions
	VariableObserver (const std::string &var_name)
	Creates a new variable observer. More...

virtual void	value_changed (const std::string &new_value)=0
	Receives a change notification. More...

virtual	~VariableObserver ()
	Deletes the observer. More...

const std::string &	observed_variable () const
	Gets the observed variable. More...

Detailed Description

Observes Environment variables.

VariableObserver offers the possibility to receive notifications when a variable is changed in an Environment.

To listen to a variable:

Create a class derived class from VariableObserver and implement function value_changed().
Create a MyObserver instance with name "my_variable", it will be automatically attached to the variable in the root Environment.

struct MyObserver : VariableObserver {
    MyObserver(const std::string& name) : VariableObserver(name) {}
    virtual void value_changed(const std::string& new_value) {
};
std::auto_ptr<MyObserver> myobserver =
    new MyObserver("my_variable");

Definition at line 83 of file environment.h.

Constructor & Destructor Documentation

◆ VariableObserver()

GEO::VariableObserver::VariableObserver ( const std::string & var_name )

Creates a new variable observer.

This creates a new observer for variable var_name and automatically adds itself to the variable's observers in the root environment.

Parameters

[in] var_name name of the variable observed.

◆ ~VariableObserver()

virtual GEO::VariableObserver::~VariableObserver ( )

virtual

Deletes the observer.

This automatically removes this observer from the root environment.

Member Function Documentation

◆ observed_variable()

const std::string& GEO::VariableObserver::observed_variable ( ) const

inline

Gets the observed variable.

Returns: The name of the variable observed by this observer.

Definition at line 113 of file environment.h.

◆ value_changed()

virtual void GEO::VariableObserver::value_changed ( const std::string & new_value )

pure virtual

Receives a change notification.

This function is called by the Environment when the variable observed by this observer is modified.