Class: StrictLazy::Batch

Inherits:
Object
  • Object
show all
Defined in:
lib/strict_lazy/batch.rb

Overview

A single StrictLazy.preload × single loader unit of work, shared by every record in the group via @batch<reader>. The resolver runs exactly once; values are written straight onto each record’s @lazy<reader> ivar, so the batch keeps no intermediate Hash and never relies on record hash-equality (unsaved records work fine).

Instance Method Summary collapse

Constructor Details

#initialize(model, records, loader) ⇒ Batch

Returns a new instance of Batch.



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# File 'lib/strict_lazy/batch.rb', line 10

def initialize(model, records, loader)
  @model = model
  @records = records
  @loader = loader
  @resolved = false
end

Instance Method Details

#resolve! ⇒ Object

Run the resolver once and write defaults for any record it skipped.



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# File 'lib/strict_lazy/batch.rb', line 24

def resolve!
  return if @resolved

  @resolved = true
  fulfilled = {}.compare_by_identity
  fulfill = lambda do |record, value|
    fulfilled[record] = true
    record.instance_variable_set(@loader.value_ivar, value)
  end

  @loader.resolve(@model, @records, fulfill)

  @records.each do |record|
    next if fulfilled.key?(record)

    record.instance_variable_set(@loader.value_ivar, @loader.default_for(record))
  end
end

#value_for(record) ⇒ Object

Resolve the value for one record, resolving the whole group on first touch.



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# File 'lib/strict_lazy/batch.rb', line 18

def value_for(record)
  resolve! unless @resolved
  record.instance_variable_get(@loader.value_ivar)
end