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