class NodeSubscription

NodeSubscription. @class_description

A NodeSubscription library implementation.

@attr instance [NodeSubscription]

A singleton instance.

@attr feeds [Set]

All subscription feeds. Its elements are hashes. The keys are Node
references, and their values are Sets containing corresponding subscribers.

NodeSubscription. @class_description

A NodeSubscription library implementation.

@attr instance [NodeSubscription]

A singleton instance.

@attr feeds [Set]

All subscription feeds. Its elements are hashes. The keys are Node
references, and their values are Sets containing corresponding subscribers.

Constants

VERSION

Public Class Methods

instance() click to toggle source

self.instance(). @description

Lazily initializes a singleton instance, or gets the singleton instance.

@return [NodeSubscription]

The singleton.

# File lib/node_subscription_impl.rb, line 23
def self.instance()
  if (@instance.nil?()) then self.instance = new() end
  return @instance
end

Private Class Methods

instance=(s = nil) click to toggle source

self.instance=(s = nil). @description

Sets the singleton instance.

@param s [NodeSubscription]

The singleton NodeSubscription instance.

@return [NodeSubscription]

The argument.

# File lib/node_subscription_impl.rb, line 200
def self.instance=(s = nil)
  @instance = s
end

new() click to toggle source

initialize(). @description

Initializes the singleton instance.

# File lib/node_subscription_impl.rb, line 189
def initialize()
  self.feeds = Set[]
end

Public Instance Methods

add_publisher(p = nil) click to toggle source

add_publisher(p = nil). @description

Adds a Node publisher.

@param p [Node]

Any instance.

@return [NilClass]

nil.

# File lib/node_subscription_impl.rb, line 78
def add_publisher(p = nil)

  publishable_set = NodeSubscription.publishable()
  p_class         = p.class()
  if (publisher(p))
    raise(ArgumentError, "#{p} was added previously.")
  elsif (!publishable_set.include?(p_class))
    raise(ArgumentError, "#{p} is not a publishable object.")
  else

    feed_hash    = {}
    feed_hash[p] = Set[]
    feeds().add(feed_hash)

  end
  return nil

end

add_subscriber(p = nil, s = nil) click to toggle source

add_subscriber(p = nil, s = nil). @description

Adds a subscriber a publisher's Set.

@param p [Node]

A publisher.

@param s [.]

Any subscribable instance.

@return [NilClass]

nil.

# File lib/node_subscription_impl.rb, line 106
  def add_subscriber(p = nil, s = nil)

    if ((!publisher(p)) || (feed(p).include?(s)) ||
        (!NodeSubscription.s_instance(s)))
      raise(ArgumentError,
            "#{p} never registered as a publisher, or #{s} was previously
subscribed.")
    else
      p_feed = feed(p)
      p_feed.add(s)
    end
    return nil

  end

publisher(p = nil) click to toggle source

publisher(p = nil). @description

Predicate. Verifies a Node is a feed publisher.

@param p [Node]

Any instance.

@return [TrueClass, FalseClass]

True in the case p is a feeds key. False otherwise.

# File lib/node_subscription_impl.rb, line 35
def publisher(p = nil)

  feeds().to_a().each { |feed|
    if (feed.key?(p)) then return true end
  }
  return false

end

update_subscribers(p = nil) click to toggle source

update_subscribers(p = nil). @description

Updates a publisher's subscribers.

@param p [Node]

A changed subject.

@return [NilClass]

nil.

# File lib/node_subscription_impl.rb, line 51
def update_subscribers(p = nil)

  unless (publisher(p))
    raise(ArgumentError, "#{p} is not a publisher.")
  else

    p_feed = feed(p)
    p_feed.each { |subscriber|

      factory   = kind_factory(subscriber)
      singleton = factory.instance()
      singleton.diagram_update(p)

    }

  end
  return nil

end

Protected Instance Methods

feed(p = nil) click to toggle source

feed(p = nil). @description

Gets a publisher's feed.

@param p [Node]

A publisher.

@return [Set]

p's feed.

@raise [ArgumentError]

In the case p is not a feeds element hash key.

# File lib/node_subscription_impl.rb, line 141
def feed(p = nil)

  if (publisher(p))

    feeds().to_a().each { |feed|
      if (feed.key?(p)) then return feed[p] end
    }

  else
    raise(ArgumentError, "#{p} was never added.")
  end

end

feeds() click to toggle source

feeds(). @description

Gets feeds.

@return [Set]

feeds' reference.

# File lib/node_subscription_impl.rb, line 128
def feeds()
  return @feeds
end

Private Instance Methods

feeds=(s = nil) click to toggle source

feeds=(s = nil). @description

Sets feeds.

@param s [Set]

An empty Set.

@return [Set]

The argument.

# File lib/node_subscription_impl.rb, line 164
def feeds=(s = nil)
  @feeds = s
end

kind_factory(s = nil) click to toggle source

kind_factory(s = nil). @description

Gets a subscriber's factory.

@param s [.]

A feed subscriber.

@return [.]

A factory identifier.

# File lib/node_subscription_impl.rb, line 175
def kind_factory(s = nil)

  case
  when s.instance_of?(NodeDiagram)
    return DiagramFactory
  else
    raise(ArgumentError, "#{s}\'s factory is nonexistent.")
  end

end