Class: Commutator::Collection

Inherits:
Object
  • Object
show all
Defined in:
lib/commutator/collection.rb,
lib/commutator/collection/cached_lookup.rb

Overview

Wraps a DynamoDB response from query or scan operations to provide a collection of instances of the given class.

NOTE: This can’t use SimpleDelegator because ‘Seahorse::Client::Response` does

not implement `#respond_to?` as needed.

Defined Under Namespace

Modules: CachedLookup

Instance Method Summary collapse

Constructor Details

#initialize(response, klass, modifiers: []) ⇒ Collection

Returns a new instance of Collection.



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# File 'lib/commutator/collection.rb', line 17

def initialize(response, klass, modifiers: [])
  @response = response
  @klass = klass
  @modifiers = modifiers.map(&:expand_proc_modifiers).freeze
end

Instance Method Details

#all_items ⇒ Object 



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# File 'lib/commutator/collection.rb', line 57

def all_items
  each_item.each_with_object([]) { |item, arr| arr << item }
end

#each_item ⇒ Object 



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# File 'lib/commutator/collection.rb', line 49

def each_item
  return enum_for(:each_item) unless block_given?

  each_page do |page|
    page.items.each { |item| yield(item) }
  end
end

#each_page ⇒ Object 



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# File 'lib/commutator/collection.rb', line 39

def each_page
  return enum_for(:each_page) unless block_given?

  response.each do |page|
    next unless page.items.present?
    page = self.class.new(page, klass, modifiers: @modifiers)
    yield(page)
  end
end

#items ⇒ Object 



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# File 'lib/commutator/collection.rb', line 23

def items
  return [] if response.items.nil?

  response.items.map do |item|
    item = klass.new(item)
    modify_item(item)
  end
end

#modify_with(*modifiers, factory: false) ⇒ Object 



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# File 'lib/commutator/collection.rb', line 61

def modify_with(*modifiers, factory: false)
  modifier = ItemModifiers.new(modifiers, factory: factory)
  # preserves decorator ordering with minimal object creation
  new_modifiers = [modifier].unshift(*@modifiers)

  self.class.new(response, klass, modifiers: new_modifiers)
end

#next_page ⇒ Object

Caution! This advances a page pointer in the response and there’s no going back. It will affect how each_page and each_item behaves. In most cases it’s better to use one of the each methods.



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# File 'lib/commutator/collection.rb', line 35

def next_page
  self.class.new(response.next_page, klass)
end