diff options
Diffstat (limited to 'lib/observer.rb')
-rw-r--r-- | lib/observer.rb | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/lib/observer.rb b/lib/observer.rb new file mode 100644 index 0000000000..9a753939a2 --- /dev/null +++ b/lib/observer.rb @@ -0,0 +1,40 @@ +# Observable Mixin +# +# Observers must respond to update + +module Observable + def add_observer(observer) + @observer_peers = [] unless @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 @observer_peers + end + def delete_observers + @observer_peers.clear if @observer_peers + end + def count_observers + if @observer_peers + @observer_peers.size + else + 0 + end + end + def changed(state=TRUE) + @observer_state = state + end + def changed? + @observer_state + end + def notify_observers(*arg) + if @observer_state + for i in @observer_peers + i.update(*arg) + end + @observer_state = FALSE + end + end +end |