Module: Glimmer::DataBinding::ObservableArray

Includes:
Observable
Defined in:
lib/glimmer/data_binding/observable_array.rb

Overview

TODO prefix utility methods with double-underscore

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Observable

#inspect

Class Method Details

.extend_object(array) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 44

def self.extend_object(array)
  # TODO consider alias_method, and define_method instead

  array.instance_eval("alias __original_add <<")
  array.instance_eval <<-end_eval, __FILE__, __LINE__
  def <<(value)
    self.__original_add(value)
    notify_observers
  end
  end_eval

  array.instance_eval("alias __original_set_value []=")
  array.instance_eval <<-end_eval, __FILE__, __LINE__
  def []=(index, value)
    old_value = self[index]
    unregister_dependent_observers(old_value)
    self.__original_set_value(index, value)
    notify_observers
  end
  end_eval

  array.instance_eval("alias __original_delete delete")
  array.instance_eval <<-end_eval, __FILE__, __LINE__
  def delete(value)
    unregister_dependent_observers(value)
    self.__original_delete(value)
    notify_observers
  end
  end_eval

  array.instance_eval("alias __original_delete_at delete_at")
  array.instance_eval <<-end_eval, __FILE__, __LINE__
  def delete_at(index)
    old_value = self[index]
    unregister_dependent_observers(old_value)
    self.__original_delete_at(index)
    notify_observers
  end
  end_eval

  array.instance_eval("alias __original_clear clear")
  array.instance_eval <<-end_eval, __FILE__, __LINE__
  def clear
    each do |old_value|
      unregister_dependent_observers(old_value)
    end
    self.__original_clear
    notify_observers
  end
  end_eval

  super
end

Instance Method Details

#add_observer(observer, element_properties = nil) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 11

def add_observer(observer, element_properties=nil)
  return observer if has_observer?(observer) && element_properties.nil?
  property_observer_list << observer
  [element_properties].flatten.compact.each do |property|
    each do |element|
      observer.observe(element, property)
    end
  end
  observer
end

#has_observer?(observer) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/glimmer/data_binding/observable_array.rb', line 32

def has_observer?(observer)
  property_observer_list.include?(observer)
end

#notify_observers ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 40

def notify_observers
  property_observer_list.each {|observer| observer.call}
end

#property_observer_list ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 36

def property_observer_list
  @property_observer_list ||= Set.new
end

#remove_observer(observer, element_properties = nil) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 22

def remove_observer(observer, element_properties=nil)
  property_observer_list.delete(observer)
  [element_properties].flatten.compact.each do |property|
    each do |element|
      observer.unobserve(element, property)
    end
  end
  observer
end

#unregister_dependent_observers(old_value) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_array.rb', line 98

def unregister_dependent_observers(old_value)
  # TODO look into optimizing this
  return unless old_value.is_a?(ObservableModel) || old_value.is_a?(ObservableArray)
  property_observer_list.each do |observer|
    observer.unregister_dependents_with_observable(observer.registration_for(self), old_value)
  end
end