Class: DataMapper::Associations::BelongsToAssociation

Inherits:
Object
  • Object
show all
Defined in:
lib/data_mapper/associations/belongs_to_association.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(instance, association_name, options) ⇒ BelongsToAssociation

Returns a new instance of BelongsToAssociation.



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 6

def initialize(instance, association_name, options)
  @instance = instance
  @association_name = association_name
  @options = options
  
  @associated_class = if options.has_key?(:class) || options.has_key?(:class_name)
    associated_class_name = (options[:class] || options[:class_name])
    if associated_class_name.kind_of?(String)
      Kernel.const_get(Inflector.classify(associated_class_name))
    else
      associated_class_name
    end
  else
    Kernel.const_get(Inflector.classify(association_name))
  end
end

Class Method Details

.setup(klass, association_name, options) ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 23

def self.setup(klass, association_name, options)
  foreign_key = options[:foreign_key] || ("#{association_name}_id")
  klass.property foreign_key.to_sym, :integer
  
  # Define the association instance method (i.e. Exhibit#zoo)
  klass.class_eval <<-EOS
    def create_#{association_name}(options = {})
      #{association_name}_association.create(options)
    end
    
    def build_#{association_name}(options = {})
      #{association_name}_association.build(options)
    end
    
    def #{association_name}
      # Let the BelongsToAssociation do the finding, just to keep things neat around here...
      #{association_name}_association.find
    end
    
    def #{association_name}=(value)
      #{association_name}_association.set(value)
    end
    
    private
      def #{association_name}_association
        @#{association_name} || (@#{association_name} = BelongsToAssociation.new(self, "#{association_name}", #{options.inspect}))
      end
  EOS
  
end

Instance Method Details

#build(options = {}) ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 84

def build(options = {})
  @result = @associated_class.new(options)
end

#create(options = {}) ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 76

def create(options = {})
  associated = @associated_class.new(options)
  if associated.save
    @instance.send("#{@associated_class.foreign_key}=", associated.id)
    @result = associated
  end
end

#find ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 54

def find
  return @result unless @result.nil?
  
  unless @instance.loaded_set.nil?
    
    # Temp variable for the instance variable name.
    setter_method = "#{@association_name}=".to_sym
    instance_variable_name = "@#{foreign_key}".to_sym
    
    set = @instance.loaded_set.instances.group_by { |instance| instance.instance_variable_get(instance_variable_name) }
    
    # Fetch the foreign objects for all instances in the current object's loaded-set.
    @instance.session.find(@associated_class, :all, :id => set.keys).each do |owner|
      set[owner.key].each do |instance|
        instance.send(setter_method, owner)
      end
    end
  end
  
  return @result
end

#foreign_key ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 92

def foreign_key
  @foreign_key ||= (@options[:foreign_key] || @instance.session.schema[@associated_class].default_foreign_key)
end

#set(val) ⇒ Object 



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# File 'lib/data_mapper/associations/belongs_to_association.rb', line 88

def set(val)
  @result = val
end