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copy_on_notify_observer_set.rb	2.8 KB	-rw-r--r--
copy_on_write_observer_set.rb	2.87 KB	-rw-r--r--
java_non_concurrent_priority_q...	2.02 KB	-rw-r--r--
non_concurrent_priority_queue....	5.42 KB	-rw-r--r--
ruby_non_concurrent_priority_q...	3.63 KB	-rw-r--r--

Code Editor : copy_on_write_observer_set.rb

require 'concurrent/synchronization'

module Concurrent
  module Collection

# A thread safe observer set implemented using copy-on-write approach:
    # every time an observer is added or removed the whole internal data structure is
    # duplicated and replaced with a new one.
    #
    # @api private
    class CopyOnWriteObserverSet < Synchronization::LockableObject

def initialize
        super()
        synchronize { ns_initialize }
      end

# @!macro observable_add_observer
      def add_observer(observer = nil, func = :update, &block)
        if observer.nil? && block.nil?
          raise ArgumentError, 'should pass observer as a first argument or block'
        elsif observer && block
          raise ArgumentError.new('cannot provide both an observer and a block')
        end

if block
          observer = block
          func = :call
        end

synchronize do
          new_observers = @observers.dup
          new_observers[observer] = func
          @observers = new_observers
          observer
        end
      end

# @!macro observable_delete_observer
      def delete_observer(observer)
        synchronize do
          new_observers = @observers.dup
          new_observers.delete(observer)
          @observers = new_observers
          observer
        end
      end

# @!macro observable_delete_observers
      def delete_observers
        self.observers = {}
        self
      end

# @!macro observable_count_observers
      def count_observers
        observers.count
      end

# Notifies all registered observers with optional args
      # @param [Object] args arguments to be passed to each observer
      # @return [CopyOnWriteObserverSet] self
      def notify_observers(*args, &block)
        notify_to(observers, *args, &block)
        self
      end

# Notifies all registered observers with optional args and deletes them.
      #
      # @param [Object] args arguments to be passed to each observer
      # @return [CopyOnWriteObserverSet] self
      def notify_and_delete_observers(*args, &block)
        old = clear_observers_and_return_old
        notify_to(old, *args, &block)
        self
      end

protected

def ns_initialize
        @observers = {}
      end

private

def notify_to(observers, *args)
        raise ArgumentError.new('cannot give arguments and a block') if block_given? && !args.empty?
        observers.each do |observer, function|
          args = yield if block_given?
          observer.send(function, *args)
        end
      end

def observers
        synchronize { @observers }
      end

def observers=(new_set)
        synchronize { @observers = new_set }
      end

def clear_observers_and_return_old
        synchronize do
          old_observers = @observers
          @observers = {}
          old_observers
        end
      end
    end
  end
end

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Code Editor : copy_on_write_observer_set.rb