Class: Zermelo::Associations::BelongsTo

Inherits:
Object
  • Object
show all
Defined in:
lib/zermelo/associations/belongs_to.rb

Instance Method Summary collapse

Constructor Details

#initialize(parent, name) ⇒ BelongsTo

NB a single instance of this class doesn’t need to care about the hash used for storage, that should be done in the save method of the parent



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# File 'lib/zermelo/associations/belongs_to.rb', line 10

def initialize(parent, name)
  @parent = parent
  @name   = name

  @backend = parent.send(:backend)

  @record_ids_key = Zermelo::Records::Key.new(
    :klass  => parent.class.send(:class_key),
    :id     => parent.id,
    :name   => 'belongs_to',
    :type   => :hash,
    :object => :association
  )

  parent.class.send(:with_association_data, name.to_sym) do |data|
    @associated_class = data.data_klass
    @lock_klasses     = [data.data_klass] + data.related_klasses
    @inverse          = data.inverse
    @callbacks        = data.callbacks
  end

  raise ':inverse_of must be set' if @inverse.nil?
  @inverse_key = "#{name}_id"
end

Instance Method Details

#value ⇒ Object 



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# File 'lib/zermelo/associations/belongs_to.rb', line 64

def value
  @parent.class.lock(*@lock_klasses) do
    # FIXME uses hgetall, need separate getter for hash/list/set
    if id = @backend.get(@record_ids_key)[@inverse_key.to_s]
    # if id = @backend.get_hash_value(@record_ids_key, @inverse_key.to_s)
      @associated_class.send(:load, id)
    else
      nil
    end
  end
end

#value=(record) ⇒ Object 



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# File 'lib/zermelo/associations/belongs_to.rb', line 35

def value=(record)
  if record.nil?
    @parent.class.lock(*@lock_klasses) do
      r = @associated_class.send(:load, @backend.get(@record_ids_key)[@inverse_key.to_s])
      bc = @callbacks[:before_clear]
      if bc.nil? || !@parent.respond_to?(bc) || !@parent.send(bc, r).is_a?(FalseClass)
        new_txn = @backend.begin_transaction
        @backend.delete(@record_ids_key, @inverse_key)
        @backend.commit_transaction if new_txn
        ac = @callbacks[:after_clear]
        @parent.send(ac, r) if !ac.nil? && @parent.respond_to?(ac)
      end
    end
  else
    raise 'Invalid record class' unless record.is_a?(@associated_class)
    raise 'Record must have been saved' unless record.persisted?
    @parent.class.lock(*@lock_klasses) do
      bs = @callbacks[:before_set]
      if bs.nil? || !@parent.respond_to?(bs) || !@parent.send(bs, r).is_a?(FalseClass)
        new_txn = @backend.begin_transaction
        @backend.add(@record_ids_key, @inverse_key => record.id)
        @backend.commit_transaction if new_txn
        as = @callbacks[:after_set]
        @parent.send(as, record) if !as.nil? && @parent.respond_to?(as)
      end
    end
  end
end