Class: N1Loader::Loader

Inherits:
Object
  • Object
show all
Includes:
ArLazyPreload::LoaderPatch
Defined in:
lib/n1_loader/core/loader.rb

Overview

Loader that performs the loading.

Subclasses must define perform method that accepts single argument and returns hash where key is the element and value is what we want to load.

Constant Summary collapse

UnsupportedArLazyPreload =

Raised when a single object without ArLazyPreload context support was passed to an isolated loader.

Class.new(StandardError)

Class Attribute Summary collapse

Attributes included from ArLazyPreload::LoaderPatch

#context_setup

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(elements, **args) ⇒ Loader

Returns a new instance of Loader.



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# File 'lib/n1_loader/core/loader.rb', line 42

def initialize(elements, **args)
  @elements = elements
  @args = args
end

Class Attribute Details

.arguments ⇒ Object (readonly)

Returns the value of attribute arguments.



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# File 'lib/n1_loader/core/loader.rb', line 10

def arguments
  @arguments
end

Class Method Details

.argument(name, **opts) ⇒ Object

Defines an argument that can be accessed within the loader.

First defined argument will have the value of first passed argument, meaning the order is important.

Parameters:

  • name (Symbol)
  • opts (Hash)

Options Hash (**opts):

  • optional (Boolean) —

    false by default

  • default (Proc) 


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# File 'lib/n1_loader/core/loader.rb', line 21

def argument(name, **opts)
  opts[:optional] = true if opts[:default]

  @arguments ||= []

  define_method(name) do
    args.fetch(name) { args[name] = opts[:default]&.call }
  end

  @arguments << opts.merge(name: name)
end

.cache_key(&block) ⇒ Object

Defines a custom cache key that is calculated for passed arguments.



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# File 'lib/n1_loader/core/loader.rb', line 34

def cache_key(&block)
  define_method(:cache_key) do
    check_arguments!
    instance_exec(&block)
  end
end

Instance Method Details

#cache_key ⇒ Object 



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# File 'lib/n1_loader/core/loader.rb', line 56

def cache_key
  check_arguments!
  args.values.map(&:object_id)
end

#for(element) ⇒ Object

Raises:



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# File 'lib/n1_loader/core/loader.rb', line 47

def for(element)
  if loaded.empty? && elements.any?
    raise NotFilled, "Nothing was preloaded, perhaps you forgot to use fulfill method"
  end
  raise NotLoaded, "The data was not preloaded for the given element" unless loaded.key?(element)

  loaded[element]
end