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require 'needle'
require 'needle/lifecycle/proxy'
require 'needle/pipeline/element'
require 'needle/thread'
class RefreshableProxy < Needle::Lifecycle::Proxy
def initialize( *args )
super
@observables = nil
end
def add_refreshable_observer( observer )
@observables ||= []
@observables.push observer
end
def refresh!
@instance = @instantiation_failed = nil
self.respond_to?( :a ) # force the instance to reload
if @observables
@observables.each { |obs| obs.refresh! }
end
end
end
class Refreshable < Needle::Pipeline::Element
set_default_priority 50
def initialize_element
@observables = options[:observe] || []
@mutex = Needle::QueryableMutex.new
@instance = nil
end
def call( *args )
return @instance if @instance
@mutex.synchronize do
return @instance if @instance
@instance = RefreshableProxy.new( succ, *args )
@observables.each { |obs| obs.add_refreshable_observer( @instance ) }
end
return @instance
end
end
def register_refreshable_model( reg )
reg.pipeline_elements[:refreshable] = Refreshable
reg.service_models[:refreshable] = [ :refreshable ]
end
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