Class: ElasticGraph::SchemaDefinition::SchemaElements::UnionType

Inherits:
Struct
  • Object
show all
Includes:
Mixins::CanBeGraphQLOnly, Mixins::HasDerivedGraphQLTypeCustomizations, Mixins::HasDirectives, Mixins::HasDocumentation, Mixins::HasIndices, Mixins::VerifiesGraphQLName
Defined in:
elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb

Overview

Defines a GraphQL union type. Use it to define an abstract supertype with one or more concrete subtypes. Each subtype must be an ObjectType, but they do not have to share any fields in common.

Examples:

Define a union type

ElasticGraph.define_schema do |schema|
  schema.object_type "Card" do |t|
    # ...
  end

  schema.object_type "BankAccount" do |t|
    # ...
  end

  schema.object_type "BitcoinWallet" do |t|
    # ...
  end

  schema.union_type "FundingSource" do |t|
    t.subtype "Card"
    t.subtypes "BankAccount", "BitcoinWallet"
  end
end

Instance Attribute Summary collapse

Attributes included from Mixins::HasIndices

#default_graphql_resolver

Attributes included from Mixins::HasDocumentation

#doc_comment

Instance Method Summary collapse

Methods included from Mixins::HasDerivedGraphQLTypeCustomizations

#customize_derived_type_fields, #customize_derived_types

Methods included from Mixins::HasIndices

#derive_indexed_type_fields, #derived_indexed_types, #directly_queryable?, #has_own_index_def?, #index, #index_def, #override_runtime_metadata, #own_index_def, #plural_root_query_field_name, #resolve_fields_with, #root_document_type?, #root_query_fields, #singular_root_query_field_name

Methods included from Mixins::HasDirectives

#directive, #directives, #directives_sdl

Methods included from Mixins::HasDocumentation

#append_to_documentation, #derived_documentation, #documentation, #formatted_documentation

Methods included from Mixins::CanBeGraphQLOnly

#graphql_only, #graphql_only?

Methods included from Mixins::VerifiesGraphQLName

verify_name!

Instance Attribute Details

#schema_def_state ⇒ State (readonly)

Returns state of the schema.

Returns:

  • (State) —

    state of the schema



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# File 'elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb', line 51

class UnionType < Struct.new(:schema_def_state, :type_ref, :subtype_refs)
  prepend Mixins::VerifiesGraphQLName
  include Mixins::CanBeGraphQLOnly
  include Mixins::HasDocumentation
  include Mixins::HasDirectives
  include Mixins::SupportsFilteringAndAggregation
  include Mixins::HasIndices
  include Mixins::HasSubtypes
  include Mixins::HasDerivedGraphQLTypeCustomizations
  include Mixins::HasReadableToSAndInspect.new { |t| t.name }

  # @private
  def initialize(schema_def_state, name)
    super(schema_def_state, schema_def_state.type_ref(name).to_final_form, Set.new) do
      yield self
    end
  end

  # @return [String] the name of the union type
  def name
    type_ref.name
  end

  # Defines a subtype of this union type.
  #
  # @param name [String] the name of an object type which is a member of this union type
  # @return [void]
  #
  # @example
  #   ElasticGraph.define_schema do |schema|
  #     schema.object_type "Card" do |t|
  #       # ...
  #     end
  #
  #     schema.union_type "FundingSource" do |t|
  #       t.subtype "Card"
  #     end
  #   end
  def subtype(name)
    type_ref = schema_def_state.type_ref(name.to_s).to_final_form

    if subtype_refs.include?(type_ref)
      raise Errors::SchemaError, "Duplicate subtype on UnionType #{self.name}: #{name}"
    end

    subtype_refs << type_ref

    # Register reverse lookup so we can efficiently find which unions contain this type
    schema_def_state.union_types_by_member_ref[type_ref] << self
  end

  # Defines multiple subtypes of this union type.
  #
  # @param names [Array<String>] names of object types which are members of this union type
  # @return [void]
  #
  # @example Define a union type
  #   ElasticGraph.define_schema do |schema|
  #     schema.object_type "BankAccount" do |t|
  #       # ...
  #     end
  #
  #     schema.object_type "BitcoinWallet" do |t|
  #       # ...
  #     end
  #
  #     schema.union_type "FundingSource" do |t|
  #       t.subtypes "BankAccount", "BitcoinWallet"
  #     end
  #   end
  def subtypes(*names)
    names.flatten.each { |n| subtype(n) }
  end

  # @return [String] the formatted GraphQL SDL of the union type
  def to_sdl
    if subtype_refs.empty?
      raise Errors::SchemaError, "UnionType type #{name} has no subtypes, but must have at least one."
    end

    "#{formatted_documentation}union #{name} #{directives_sdl(suffix_with: " ")}= #{subtype_refs.map(&:name).to_a.join(" | ")}"
  end

  # Union types cannot themselves be members of other unions or implement interfaces,
  # so they have no supertypes.
  #
  # @return [Set] empty set
  # @private
  def recursively_resolve_supertypes
    Set[]
  end

  # @private
  def verify_graphql_correctness!
    # Nothing to verify. `verify_graphql_correctness!` will be called on each subtype automatically.
  end

  # Various things check `mapping_options` on indexed types (usually object types, but can also happen on union types).
  # We need to implement `mapping_options` here to satisfy those method calls, but we will never use custom mapping on
  # a union type so we hardcode it to return nil.
  #
  # @private
  def mapping_options
    {}
  end

  private

  def resolve_subtypes
    subtype_refs.map do |ref|
      ref.as_object_type || raise(
        Errors::SchemaError, "The subtype `#{ref}` of the UnionType `#{name}` is not a defined object type."
      )
    end
  end
end

Instance Method Details

#name ⇒ String

Returns the name of the union type.

Returns:

  • (String) —

    the name of the union type



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# File 'elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb', line 70

def name
  type_ref.name
end

#subtype(name) ⇒ void

This method returns an undefined value.

Defines a subtype of this union type.

Examples:

ElasticGraph.define_schema do |schema|
  schema.object_type "Card" do |t|
    # ...
  end

  schema.union_type "FundingSource" do |t|
    t.subtype "Card"
  end
end

Parameters:

  • name (String) —

    the name of an object type which is a member of this union type



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# File 'elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb', line 89

def subtype(name)
  type_ref = schema_def_state.type_ref(name.to_s).to_final_form

  if subtype_refs.include?(type_ref)
    raise Errors::SchemaError, "Duplicate subtype on UnionType #{self.name}: #{name}"
  end

  subtype_refs << type_ref

  # Register reverse lookup so we can efficiently find which unions contain this type
  schema_def_state.union_types_by_member_ref[type_ref] << self
end

#subtypes(*names) ⇒ void

This method returns an undefined value.

Defines multiple subtypes of this union type.

Examples:

Define a union type

ElasticGraph.define_schema do |schema|
  schema.object_type "BankAccount" do |t|
    # ...
  end

  schema.object_type "BitcoinWallet" do |t|
    # ...
  end

  schema.union_type "FundingSource" do |t|
    t.subtypes "BankAccount", "BitcoinWallet"
  end
end

Parameters:

  • names (Array<String>) —

    names of object types which are members of this union type



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# File 'elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb', line 121

def subtypes(*names)
  names.flatten.each { |n| subtype(n) }
end

#to_sdl ⇒ String

Returns the formatted GraphQL SDL of the union type.

Returns:

  • (String) —

    the formatted GraphQL SDL of the union type



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# File 'elasticgraph-schema_definition/lib/elastic_graph/schema_definition/schema_elements/union_type.rb', line 126

def to_sdl
  if subtype_refs.empty?
    raise Errors::SchemaError, "UnionType type #{name} has no subtypes, but must have at least one."
  end

  "#{formatted_documentation}union #{name} #{directives_sdl(suffix_with: " ")}= #{subtype_refs.map(&:name).to_a.join(" | ")}"
end