Created
February 15, 2019 02:51
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Command Pattern - notifications and observers
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module RJ | |
module Utils | |
module Commands | |
module Notifications | |
extend ActiveSupport::Concern | |
module ClassMethods | |
def observer(*observer_methods, of_event: :success) | |
observer_methods.each do |observer| | |
observers[of_event] ||= Set.new | |
observers[of_event] << observer | |
end | |
end | |
def observers | |
@observers ||= {} | |
end | |
end | |
def notify_observers(of_event: :success) | |
observers_array.each { |observer| safe_call observer } | |
rescue StandardError => e | |
Rails.logger.warn "#{self.class} observers failed with #{e.message}" | |
Rails.logger.debug e.backtrace.join("\n") | |
end | |
def observers | |
@observers ||= | |
self.class.observers.each_with_object({}) do |(event, observer_methods), observers| | |
observer_methods.each do |meth| | |
observers[event] ||= Set.new | |
observers[event] << send(meth) | |
end | |
end | |
end | |
private | |
def observers_array(of_event: :success) | |
Array(observers[of_event]).compact | |
end | |
def safe_call(observer) | |
if observer.respond_to?(:call) | |
observer.call | |
else | |
send observer | |
end | |
end | |
end | |
end | |
end | |
end |
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