class NodeObserver - node_observer_impl-0.1.0 Documentation

Public Class Methods

instance() click to toggle source

self.instance(). @description

Gets instance. Lazily initializes instance.

@return [NodeObserver]

The instance.

# File lib/node_observer_impl.rb, line 20
def self.instance()

  if (@instance.nil?())
    self.instance = new()
  end
  return @instance

end

Private Class Methods

instance=(singleton = nil) click to toggle source

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

Sets the singleton instance.

@param singleton [NodeObserver]

The instance.

@return [NodeObserver]

The argument.

# File lib/node_observer_impl.rb, line 225
def self.instance=(singleton = nil)
  @instance = singleton
  return @instance
end

new() click to toggle source

initialize(). @description

Initializes the singleton instance's instance variables.

# File lib/node_observer_impl.rb, line 213
def initialize()
  self.observing = Set[]
  self.changed = Set[]
end

Public Instance Methods

add(n = nil) click to toggle source

add(n = nil). @description

Adds observing a subject.

@param n [Node]

The addition.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 70
def add(n = nil)

  unless (n.instance_of?(Node))
    raise(ArgumentError, "#{n} is not a Node instance.")
  else
    observing().add(n)
  end
  return nil

end

changed_node(subject = nil) click to toggle source

changed_node(subject = nil). @description

Predicate. Verifies a subject was changed.

@param subject [Node]

Any instance.

@return [TrueClass, FalseClass]

True in the case the argument is a 'changed' element. False otherwise.

# File lib/node_observer_impl.rb, line 47
def changed_node(subject = nil)
  return (changed().include?(subject))
end

remove(n = nil) click to toggle source

remove(n = nil). @description

Removes a subject.

@param n [Node]

The removal.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 88
def remove(n = nil)

  unless (subject(n))
    raise(ArgumentError, "#{n} is not a subject.")
  else
    observing().delete(n)
  end
  return nil

end

subject(n = nil) click to toggle source

subject(n = nil). @description

Predicate. Verifies a Node is a subject.

@param n [Node]

Any instance.

@return [TrueClass, FalseClass]

True in the case the argument is an 'observing' element. False otherwise.

# File lib/node_observer_impl.rb, line 36
def subject(n = nil)
  return (observing().include?(n))
end

subject_changed(subject = nil) click to toggle source

subject_changed(subject = nil). @description

Adds an existing subject the changed Set.

@param subject [Node]

A subject.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 58
def subject_changed(subject = nil)
  receive_change(subject)
  return nil
end

Protected Instance Methods

add_changed(n = nil) click to toggle source

add_changed(n = nil). @description

Adds changed a changed subject.

@param n [Node]

A changed subject.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 126
def add_changed(n = nil)

  unless (subject(n))
    raise(ArgumentError, "#{n} is not a subject.")
  else
    changed().add(n)
  end
  return nil

end

changed() click to toggle source

changed(). @description

Gets changed.

@return [Set]

changed's reference.

# File lib/node_observer_impl.rb, line 115
def changed()
  return @changed
end

notify(n = nil) click to toggle source

notify(n = nil). @description

Updates a subject's subscribers.

@param n [Node]

A changed subject.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 163
def notify(n = nil)

  Subscription.update(n)
  remove_changed(n)
  return nil

end

observing() click to toggle source

observing(). @description

Gets 'observing'.

@return [Set]

observing's reference.

# File lib/node_observer_impl.rb, line 106
def observing()
  return @observing
end

remove_changed(n = nil) click to toggle source

remove_changed(n = nil). @description

Removes a changed subject. Calls after a Subscription update call.

@param n [Node]

A changed element. The element's subscribers were updated, so it is an
unchanged subject.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 145
def remove_changed(n = nil)

  unless (changed_node(n))
    raise(ArgumentError, "#{n} is not a changed subject.")
  else
    changed().delete(n)
  end
  return nil

end

Private Instance Methods

changed=(s = nil) click to toggle source

changed=(s = nil). @description

Sets 'changed'.

@param s [Set]

An empty set.

@return [Set]

The argument.

# File lib/node_observer_impl.rb, line 191
def changed=(s = nil)
  @changed = s
end

observing=(s = nil) click to toggle source

observing=(s = nil). @description

Sets observing.

@param s [Set]

An empty set.

@return [Set]

The argument.

# File lib/node_observer_impl.rb, line 180
def observing=(s = nil)
  @observing = s
end

receive_change(n = nil) click to toggle source

receive_change(n = nil). @description

Receives a Node's state change.

@param n [Node]

An existing subject.

@return [NilClass]

nil.

# File lib/node_observer_impl.rb, line 202
def receive_change(n = nil)

  add_changed(n)
  notify(n)
  return nil

end