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Contents
#
#
# Ruby Notify like class
#
# Ref: https://ozone.wordpress.com/category/programming/metaprogramming/
##
# Listeners implement:
#
# def attribute_changed(attr, old, new)
# ...
# end
#
#
module SknUtils
class NotifierBase
def initialize
@listeners = []
end
def register_listener(listener)
@listeners.push(listener) unless @listeners.include?(listener)
end
def unregister_listener(listener)
@listeners.delete(listener)
end
# create writer-with-notify and reader
def self.attribute(*attrs)
attrs.each do |attr|
instance_variable_set("@#{attr}", nil)
define_method(attr) do
instance_variable_get("@#{attr}")
end
define_method("#{attr}=") do |value|
old_value = instance_variable_get("@#{attr}")
unless (value == old_value)
instance_variable_set("@#{attr}", value)
@listeners.each do |listener|
listener.attribute_changed(attr, old_value, value)
end
end
end
end # loop on attrs
end # end of attribute method
end # end of NotifierBase class
end
Version data entries
18 entries across 18 versions & 1 rubygems