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Class: ActiveRecord::Promise

Relationships & Source Files
Namespace Children
Classes:
Complete
Extension / Inclusion / Inheritance Descendants
Subclasses:
Complete
Inherits: BasicObject
Defined in: activerecord/lib/active_record/promise.rb

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(future_result, block) ⇒ Promise

This method is for internal use only.
[ GitHub ] 

  


# File 'activerecord/lib/active_record/promise.rb', line 7



def initialize(future_result, block) # :nodoc:
  @future_result = future_result
  @block = block
end


  







Instance Attribute Details



  

    #pending?  ⇒ Boolean  (readonly)
  



  

    

Returns whether the associated query is still being executed or not.


  





  


  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 13



def pending?
  @future_result.pending?
end


  







Instance Method Details



  

    #inspect  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 44



def inspect # :nodoc:
  "#<ActiveRecord::Promise status=#{status}>"
end


  








  

    #pretty_print(q)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 48



def pretty_print(q) # :nodoc:
  q.text(inspect)
end


  








  

    #status   (private)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 53



def status
  if @future_result.pending?
    :pending
  elsif @future_result.canceled?
    :canceled
  else
    :complete
  end
end


  








  

    #then(&block)  
  



  

    

Returns a new Promise that will apply the passed block when the value is accessed:



Post.async_pick(:title).then { |title| title.upcase }.value
# => "POST TITLE"


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 36



def then(&block)
  Promise.new(@future_result, @block ? @block >> block : block)
end


  








  

    #value  
  



  

    

Returns the query result. If the query wasn’t completed yet, accessing #value will block until the query completes. If the query failed, #value will raise the corresponding error.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/promise.rb', line 20



def value
  return @value if defined? @value

  result = @future_result.result
  @value = if @block
    @block.call(result)
  else
    result
  end
end