class GraphQL::Schema::PossibleTypes

Find the members of a union or interface within a given schema.

(Although its members never change, unions are handled this way to simplify execution code.)

Internally, the calculation is cached. It's assumed that schema members _don't_ change after creating the schema!

@example Get an interface's possible types

possible_types = GraphQL::Schema::PossibleTypes(MySchema)
possible_types.possible_types(MyInterface)
# => [MyObjectType, MyOtherObjectType]

Public Class Methods

new(schema) click to toggle source
# File lib/graphql/schema/possible_types.rb, line 15
def initialize(schema)
  @object_types = schema.types.values.select { |type| type.kind.object? }

  @interface_implementers = Hash.new do |hash, key|
    hash[key] = @object_types.select { |type| type.interfaces.include?(key) }.sort_by(&:name)
  end
end

Public Instance Methods

possible_types(type_defn) click to toggle source
# File lib/graphql/schema/possible_types.rb, line 23
def possible_types(type_defn)
  case type_defn
  when Module
    possible_types(type_defn.graphql_definition)
  when GraphQL::UnionType
    type_defn.possible_types
  when GraphQL::InterfaceType
    @interface_implementers[type_defn]
  when GraphQL::BaseType
    [type_defn]
  else
    raise "Unexpected possible_types object: #{type_defn.inspect}"
  end
end