Maven module :un.api : api-common :
Class : un.api.predicate.Variable
Extends/Implements : un.api.event.EventSource
Subclasses : -

A variable is a value which may change overtime for any reason.
Variables produces events when they change.
author Johann Sorel

Variables : -
Functions : getHolder, isReadable, isWritable, sync, sync, unsync, getValue, setValue, addListener, removeListener

The main object that contains this variable.
Variables may be short life objects, when holding weak or soft reference
it is then important to keep a reference to the real object.
return main object or itself if variable is self contained.

EventSource getHolder ()

Indicate if getValue method is usable.
return true if variable is readable

boolean isReadable ()

Indicate if setValue method is usable.
return true if variable is writable

boolean isWritable ()

Synchronize the value of this variable with given one.
This synchronization in both in reading and writing.
param var not null , value type must match

void sync (Variable var)

Synchronize the value of this variable with given one.
param var not null , value type must match
param readOnly true to synchronize reading only.

void sync (Variable var, boolean readOnly)

Remove any synchronizion in place with this variable.
The method has no effect if there is no synchronization.

void unsync ()

Get variable value.
return value variable value
throws RuntimeException if value is not readable or an error occured

Object getValue ()

Set variable value.
param value new variable value
throws RuntimeException if value is not writable or an error occured

void setValue (Object value)

Add a listener which will receive VariableEvent when value changes.
param listener

void addListener (EventListener listener)

Remove variable listener.
param listener

void removeListener (EventListener listener)