Module: Glimmer::DataBinding::ObservableModel

Includes:
Observable
Included in:
UI::CustomWidget
Defined in:
lib/glimmer/data_binding/observable_model.rb

Overview

TODO prefix utility methods with double-underscore

Defined Under Namespace

Classes: Notifier

Instance Method Summary collapse

Instance Method Details

#add_observer(observer, property_name) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 23

def add_observer(observer, property_name)
  return observer if has_observer?(observer, property_name)
  property_observer_list(property_name) << observer
  add_property_writer_observers(property_name)
  observer
end

#add_property_writer_observers(property_name) ⇒ Object

TODO upon updating values, make sure dependent observers are cleared (not added as dependents here)



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# File 'lib/glimmer/data_binding/observable_model.rb', line 58

def add_property_writer_observers(property_name)
  property_writer_name = "#{property_name}="
  method(property_writer_name)
  ensure_array_object_observer(property_name, send(property_name))
  begin
    method("__original_#{property_writer_name}")
  rescue
    # TODO consider alias_method or define_method instead
    instance_eval "alias __original_#{property_writer_name} #{property_writer_name}"
    instance_eval <<-end_eval, __FILE__, __LINE__
    def #{property_writer_name}(value)
      old_value = self.#{property_name}
      unregister_dependent_observers('#{property_name}', old_value)
      self.__original_#{property_writer_name}(value)
      notify_observers('#{property_name}')
      ensure_array_object_observer('#{property_name}', value, old_value)
    end
    end_eval
  end
rescue => e
  # ignore writing if no property writer exists
  Glimmer.logger&.debug "No need to observe property writer: #{property_writer_name}\n#{e.message}\n#{e.backtrace.join("\n")}"
end

#array_object_observer_for(property_name) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 101

def array_object_observer_for(property_name)
  @array_object_observers ||= {}
  unless @array_object_observers.has_key?(property_name)
    @array_object_observers[property_name] = ObservableModel::Notifier.new(self, property_name)
  end
  @array_object_observers[property_name]
end

#ensure_array_object_observer(property_name, object, old_object = nil) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 90

def ensure_array_object_observer(property_name, object, old_object = nil)
  return unless object.is_a?(Array)
  array_object_observer = array_object_observer_for(property_name)
  array_observer_registration = array_object_observer.observe(object)
  property_observer_list(property_name).each do |observer|
    my_registration = observer.registration_for(self, property_name) # TODO eliminate repetition
    observer.add_dependent(my_registration => array_observer_registration)
  end
  array_object_observer_for(property_name).unregister(old_object) if old_object.is_a?(ObservableArray)
end

#has_observer?(observer, property_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/glimmer/data_binding/observable_model.rb', line 34

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

#has_observer_for_any_property?(observer) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/glimmer/data_binding/observable_model.rb', line 38

def has_observer_for_any_property?(observer)
  property_observer_hash.values.map(&:to_a).sum.include?(observer)
end

#notify_observers(property_name) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 53

def notify_observers(property_name)
  property_observer_list(property_name).each {|observer| observer.call(send(property_name))}
end

#property_observer_hash ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 42

def property_observer_hash
  # TODO simplify with ||=
  @property_observers = Hash.new unless @property_observers
  @property_observers
end

#property_observer_list(property_name) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 48

def property_observer_list(property_name)
  property_observer_hash[property_name.to_sym] = Set.new unless property_observer_hash[property_name.to_sym]
  property_observer_hash[property_name.to_sym]
end

#remove_observer(observer, property_name) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 30

def remove_observer(observer, property_name)
  property_observer_list(property_name).delete(observer)
end

#unregister_dependent_observers(property_name, old_value) ⇒ Object 



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# File 'lib/glimmer/data_binding/observable_model.rb', line 82

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