Class: InventoryRefresh::ApplicationRecordIterator

Inherits:
Object
  • Object
show all
Defined in:
lib/inventory_refresh/application_record_iterator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(inventory_collection: nil, manager_uuids_set: nil, iterator: nil, query: nil) ⇒ ApplicationRecordIterator

An iterator that can fetch batches of the AR objects based on a set of manager refs, or just mimics AR relation when given an iterator. Or given query, acts as iterator by selecting batches.

Parameters:



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 13

def initialize(inventory_collection: nil, manager_uuids_set: nil, iterator: nil, query: nil)
  @inventory_collection = inventory_collection
  @manager_uuids_set    = manager_uuids_set
  @iterator             = iterator
  @query                = query
end

Instance Attribute Details

#inventory_collection ⇒ Object (readonly)

Returns the value of attribute inventory_collection.



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 3

def inventory_collection
  @inventory_collection
end

#iterator ⇒ Object (readonly)

Returns the value of attribute iterator.



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 3

def iterator
  @iterator
end

#manager_uuids_set ⇒ Object (readonly)

Returns the value of attribute manager_uuids_set.



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 3

def manager_uuids_set
  @manager_uuids_set
end

#query ⇒ Object (readonly)

Returns the value of attribute query.



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 3

def query
  @query
end

Instance Method Details

#find_each { ... } ⇒ Object

Iterator that mimics find_each of ActiveRecord::Relation using find_in_batches (see #find_in_batches)

Yields:

  • Code processing the batches



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 46

def find_each(&block)
  find_in_batches do |batch|
    batch.each(&block)
  end
end

#find_in_batches(batch_size: 1000) { ... } ⇒ Object

Iterator that mimics find_in_batches of ActiveRecord::Relation. This iterator serves for making more optimized query since e.g. having 1500 ids if objects we want to return. Doing relation.where(:id => 1500ids).find_each would always search for all 1500 ids, then return on limit 1000.

With this iterator we build queries using only batch of ids, so find_each will cause relation.where(:id => 1000ids) and relation.where(:id => 500ids)

Parameters:

  • batch_size (Integer) (defaults to: 1000) —

    A batch size we want to fetch from DB

Yields:

  • Code processing the batches



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# File 'lib/inventory_refresh/application_record_iterator.rb', line 29

def find_in_batches(batch_size: 1000, &block)
  if iterator
    iterator.call(&block)
  elsif query
    manager_uuids_set.each_slice(batch_size) do |batch|
      yield(query.where(inventory_collection.targeted_selection_for(batch)))
    end
  else
    manager_uuids_set.each_slice(batch_size) do |batch|
      yield(inventory_collection.db_collection_for_comparison_for(batch))
    end
  end
end