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Class: Mongo::CachingCursor

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Cursor, Forwardable
Instance Chain:
self, Cursor, Retryable, Enumerable
Inherits: Mongo::Cursor
Defined in: lib/mongo/caching_cursor.rb

Overview

A Cursor that attempts to load documents from memory first before hitting the database if the same query has already been executed.

Class Method Summary

Cursor - Inherited

.finalize

Finalize the cursor for garbage collection.
.new

Creates a Cursor object.

Instance Attribute Summary

Cursor - Inherited

#closed?

Is the cursor closed?
#fully_iterated?, #initial_result,
#resume_token

The resume token tracked by the cursor for change stream resuming.
#server, #view, #exhausted?, #explicitly_closed?, #limited?, #use_limit?

Instance Method Summary

  • #each

    We iterate over the cached documents if they exist already in the cursor otherwise proceed as normal.

  • #inspect ⇒ String

    Get a human-readable string representation of Cursor.

  • #try_next Internal use only Internal use only

    Acquires the next document for cursor iteration and then inserts that document in the @cached_docs array.

Cursor - Inherited

#batch_size

Get the batch size.
#close

Closes this cursor, freeing any associated resources on the client and the server.
#collection_name

Get the parsed collection name.
#each

Iterate through documents returned from the query.
#get_more

Execute a getMore command and return the batch of documents obtained from the server.
#id

Get the cursor id.
#inspect

Get a human-readable string representation of Cursor.
#kill_spec,
#to_return

Get the number of documents to return.
#try_next

Return one document from the query, if one is available.
#batch_size_for_get_more, #cache_batch_resume_token, #cache_resume_token, #end_session, #execute_operation, #get_more_operation, #limit, #process, #register,
#set_cursor_id

Sets @cursor_id from the operation result.
#unregister

Retryable - Included

#read_worker

Returns the read worker for handling retryable reads.
#select_server

This is a separate method to make it possible for the test suite to assert that server selection is performed during retry attempts.
#write_worker

Returns the write worker for handling retryable writes.

Instance Attribute Details

#cached_docs ⇒ Array <BSON::Document> (readonly)

This method is for internal use only.

Returns:

  • (Array <BSON::Document>) —

    The cursor’s cached documents.

[ GitHub ] 

  


# File 'lib/mongo/caching_cursor.rb', line 28



attr_reader :cached_docs


  







Instance Method Details



  

    #each  
  



  

    

We iterate over the cached documents if they exist already in the cursor otherwise proceed as normal.


  





    

    
Examples:

        


Iterate over the documents.



      
cursor.each do |doc|
  # ...
end

  




  [ GitHub ]


  

  


# File 'lib/mongo/caching_cursor.rb', line 37



def each
  if @cached_docs
    @cached_docs.each do |doc|
      yield doc
    end

    unless closed?
      # StopIteration raised by try_next ends this loop.
      loop do
        document = try_next
        yield document if document
      end
    end
  else
    super
  end
end


  








  

    #inspect  ⇒ String 
  



  

    

Get a human-readable string representation of Cursor.


  





    

    
Examples:

        


Inspect the cursor.



      
cursor.inspect

  


Returns:


    
  
  • 
    (String)
—    
    

    A string representation of a Cursor instance.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/caching_cursor.rb', line 61



def inspect
  "#<Mongo::CachingCursor:0x#{object_id} @view=#{@view.inspect}>"
end


  








  

    #try_next  
  

  

    This method is for internal use only.
  



  

    

Acquires the next document for cursor iteration and then inserts that document in the @cached_docs array.


  





  


  [ GitHub ]


  

  


# File 'lib/mongo/caching_cursor.rb', line 69



def try_next
  @cached_docs ||= []
  document = super
  @cached_docs << document if document

  document
end