Class: Bronze::Entities::Attributes::Builder

Inherits:
Object
  • Object
show all
Defined in:
lib/bronze/entities/attributes/builder.rb

Overview

Service class to define attributes on an entity.

Constant Summary collapse

VALID_OPTIONS =

Provides a list of the valid options for the attribute_options parameter for Builder#build.

%w[
  allow_nil
  default
  default_transform
  foreign_key
  primary_key
  read_only
  transform
].map(&:freeze).freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(entity_class) ⇒ Builder

Returns a new instance of Builder.

Parameters:

  • entity_class (Class) —

    The entity class on which attributes will be defined.



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# File 'lib/bronze/entities/attributes/builder.rb', line 76

def initialize(entity_class)
  @entity_class = entity_class
end

Instance Attribute Details

#entity_class ⇒ Class (readonly)

Returns the entity class on which attributes will be defined.

Returns:

  • (Class) —

    the entity class on which attributes will be defined.



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# File 'lib/bronze/entities/attributes/builder.rb', line 81

def entity_class
  @entity_class
end

Class Method Details

.attribute_transform(type, transform) ⇒ Object

Registers a transform as the default transform for attributes with the specified type or a subtype of the specified type.

This default is not retroactive - any attributes already defined will use their existing default transform, if any. If more than one registered transform has a matching type, the most recently defined transform will be used.

Parameters:

  • type (Class) —

    The attribute type. When defining an attribute, if the type of the attribute is this class or a subclass of this class and no :transform option is given, the transform for the attribute will be the transform passed to ::attribute_transform.

  • transform (Class, Bronze::Transforms::Transform) —

    The transform to use as the default. If this value is a transform instance, the default transform for matching attributes will be the given transform. Otherwise, will set the default transform to the result of ::instance (if defined) or ::new.



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# File 'lib/bronze/entities/attributes/builder.rb', line 44

def attribute_transform(type, transform)
  (@attribute_transforms ||= {})[type] = transform
end

Instance Method Details

#build(attribute_name, attribute_type, attribute_options = {}) ⇒ Attributes::Metadata

Defines an attribute on the entity class.

Examples:

Defining an Attribute

class Book < Bronze::Entities::Entity; end

book = Book.new
book.title
#=> NoMethodError: undefined method `title'

builder = Bronze::Entities::Attributes::Builder.new(Book)
builder.define_attribute :title, String

book.title
#=> nil

book.title = 'Romance of the Three Kingdoms'
book.title
#=> 'Romance of the Three Kingdoms'

Parameters:

  • attribute_name (Symbol, String) —

    The name of the attribute to define.

  • attribute_type (Class) —

    The type of the attribute to define.

  • attribute_options (Hash) (defaults to: {}) —

    Additional options for building the attribute.

Options Hash (attribute_options):

  • :default (Object, Proc) —

    The default value for the attribute. If the attribute value is nil or has not been set, the attribute will be set to the default. If the default is a Proc, the Proc will be called each time and the attribute set to the return value. Otherwise, the attribute will be set to the default value.

  • :default_transform (Boolean) —

    If a transform is set, marks the transform as a default transform, which can be overriden when normalizing the attribute.

  • :foreign_key (Boolean) —

    Marks the attribute as a foreign key. Will be set to true by association builders, and generally should not be set manually. Defaults to false.

  • :read_only (Boolean) —

    If true, the writer method for the attribute will be set as private. Defaults to false.

  • :transform (Class, Bronze::Transform) —

    If set, the attribute will be normalized using this transform. By default, certain attribute types will be transformed - BigDecimal, Date, DateTime, Symbol, and Time.

Returns:

Raises:

  • Builder::Error if the attribute name or attribute type is missing or invalid.



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# File 'lib/bronze/entities/attributes/builder.rb', line 131

def build(attribute_name, attribute_type, attribute_options = {})
  validate_attribute_name(attribute_name)
  validate_attribute_opts(attribute_options)

  characterize(
    attribute_name,
    attribute_type,
    attribute_options
  )
    .tap { |metadata| define_property_methods(metadata) }
end