ruby/lib/observer.rb

47 строки
1006 B
Ruby

# Observable Mixin
#
# Observers must respond to update
module Observable
def add_observer(observer)
@observer_peers = [] unless defined? @observer_peers
unless defined? observer.update
raise NameError, "observer needs to respond to `update'"
end
@observer_peers.push observer
end
def delete_observer(observer)
@observer_peers.delete observer if defined? @observer_peers
end
def delete_observers
@observer_peers.clear if defined? @observer_peers
end
def count_observers
if defined? @observer_peers
@observer_peers.size
else
0
end
end
def changed(state=true)
@observer_state = state
end
def changed?
if defined? @observer_state and @observer_state
true
else
false
end
end
def notify_observers(*arg)
if defined? @observer_state and @observer_state
if defined? @observer_peers
for i in @observer_peers.dup
i.update(*arg)
end
end
@observer_state = false
end
end
end