root/lu/LUNotification.lua

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-- Title:               LUNotification.lua
-- Description:         Like a square peg in a round hole
-- Author:              Raphaël Szwarc http://alt.textdrive.com/lua/
-- Creation Date:       February 1, 2005
-- Legal:               Copyright (C) 2005 Raphaël Szwarc
--------------------------------------------------------------------------------

-- import dependencies
local LUObject = require( "LUObject" )
local LUMap = require( "LUMap" )

-- define the class
local super = LUObject
local self = super()

function self:default()
        if self:class()._default == nil then
                self:class()._default = self:new()
        end
        
        return self:class()._default
end

function self:map()
        if self._map == nil then
                self._map = LUMap()
        end
        
        return self._map
end

function self:addObserver( anObserver, aNotification, aMethod )
        if anObserver ~= nil and aNotification ~= nil then
                local aMap = self:map()
                local someObservers = aMap:get( aNotification )
                
                if someObservers == nil then
                        someObservers = LUMap( nil, "k" )
                        aMap:put( aNotification, someObservers )
                end
                
                someObservers:put( anObserver, aMethod or "notify" )
        end
        
        return self
end

function self:removeObserver( anObserver, aNotification )
        if anObserver ~= nil and aNotification ~= nil then
                local someObservers = self:map():get( aNotification )
                
                if someObservers ~= nil then
                        someObservers:remove( anObserver )
                end  
        end      
        
        return self
end

function self:post( aNotification, ... )
        if aNotification ~= nil then
                local someObservers = self:map():get( aNotification )
                
                if someObservers ~= nil then
                        for anObserver, aMethod in someObservers:iterator() do
                                if type( aMethod ) == "string" then
                                        anObserver:invoke( aMethod, aNotification, ... )
                                else
                                        aMethod( aNotification, ... )
                                end              
                        end 
                end
        end
        
        return self
end

return self