Class: EnumeratedType::PropertyIndex

Inherits:
Object
  • Object
show all
Defined in:
lib/enumerated_type.rb

Overview

In the unfortunate case where there are thousands of elements in an enumerated type, an iteration based strategy for EnumeratedType.by is slow. Particularly, since declare does .by(:name, name) to detect name collisions, EnumeratedType.declare is O(n^2) where n is the EnumeratedType.count, which can take seconds when the enunm is loaded, which is, like, a total bummer. This class indexes enums by property and value so lookups are constant time. The backing hash would look like this for the Shape enum.

{

:sides => {
  4 => Shape::Square
},
:name => {
  :square => Shape::Square
}

}

Note that there is only a single value for each property/value combination. #set will respect the first instance of a property/value combination (i.e subsequent duplicate #sets will not override the first value). This matches the definition of EnumeratedType.by.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ PropertyIndex

Returns a new instance of PropertyIndex.



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# File 'lib/enumerated_type.rb', line 27

def initialize
  self.by_property = { }
end

Instance Method Details

#get(property, value, miss) ⇒ Object 



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# File 'lib/enumerated_type.rb', line 36

def get(property, value, miss)
  by_property.fetch(property.to_sym).fetch(value, &miss)
end

#has_property?(property) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/enumerated_type.rb', line 40

def has_property?(property)
  by_property.has_key?(property.to_sym)
end

#set(property, value, enumerated) ⇒ Object 



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# File 'lib/enumerated_type.rb', line 31

def set(property, value, enumerated)
  by_value = (by_property[property.to_sym] ||= { })
  by_value[value] ||= enumerated
end