code snippets for "Auto-Wiring Ruby Events" post

s1.rb

class Publisher
    include EventPublisher
    event :first_event
    event :second_event
     
    def trigger_events
        trigger :first_event, "first event"
        trigger :second_event, "second event"
    end
end

s2.rb

@publisher.subscribe :first_event, method(:first_event_handler)
@publisher.subscribe :second_event, method(:second_event_handler)

s3.rb

@publisher.subscribe_all self

s4.rb

class Subscriber
    def initialize(publisher)
        @publisher = publisher
        @publisher.subscribe_all self
    end
     
    def stop_listening
        @publisher.unsubscribe_all self
    end
     
    def first_event_handler(args)
        puts args
    end
     
    def second_event_handler(args)
        puts args
    end
end

s5.rb

def each_suitable_handler(subscriber)
    possible_handlers = subscriber.class.instance_methods.select { |name| name =~ /\w_handler/ }
    possible_handlers.each do |method_name|
        event_name = /(?<event_name>.*)_handler/.match(method_name)[:event_name] 
        if EVENTS.include? event_name.to_sym
            yield event_name.to_sym, method_name.to_sym
        end
    end
end
 
def subscribe_all(subscriber)
    each_suitable_handler(subscriber) do |event_symbol, method_symbol|
        subscribe event_symbol, subscriber.method(method_symbol)
    end
end
 
def unsubscribe_all(subscriber)
    each_suitable_handler(subscriber) do |event_symbol, method_symbol|
        unsubscribe event_symbol, subscriber.method(method_symbol)
    end
end

s6.rb

self.class.class_eval do
    EVENTS = []
 
    def event(symbol)
        getter = symbol
        variable = :"@#{symbol}"
        EVENTS << symbol
 
        define_method getter do
            event = instance_variable_get variable
 
            if event == nil
                event = Event.new(symbol.to_s)
                instance_variable_set variable, event
            end
 
            event
        end
    end
end

s7.rb

publisher = Publisher.new
subscriber = Subscriber.new(publisher)
publisher.trigger_events
subscriber.stop_listening
publisher.trigger_events