Module: FedoraLens::AttributeMethods::Read

Extended by:
Defined in:

Defined Under Namespace

Modules: ClassMethods

Constant Summary collapse

ReaderMethodCache = {
  # We want to generate the methods via module_eval rather than
  # define_method, because define_method is slower on dispatch.
  # Evaluating many similar methods may use more memory as the instruction
  # sequences are duplicated and cached (in MRI).  define_method may
  # be slower on dispatch, but if you're careful about the closure
  # created, then define_method will consume much less memory.
  # But sometimes the database might return columns with
  # characters that are not allowed in normal method names (like
  # 'my_column(omg)'. So to work around this we first define with
  # the __temp__ identifier, and then use alias method to rename
  # it to what we want.
  # We are also defining a constant to hold the frozen string of
  # the attribute name. Using a constant means that we do not have
  # to allocate an object on each call to the attribute method.
  # Making it frozen means that it doesn't get duped when used to
  # key the @attributes_cache in read_attribute.
  def method_body(method_name, const_name)
    def #{method_name}
      name = ::FedoraLens::AttributeMethods::AttrNames::ATTR_#{const_name}
      read_attribute(name) { |n| missing_attribute(n, caller) }

Instance Method Summary collapse

Instance Method Details

#read_attribute(attr_name) ⇒ Object

Returns the value of the attribute identified by attr_name after it has been typecast (for example, “2004-12-12” in a date column is cast to a date object, like, 12, 12)).

# File 'lib/fedora_lens/attribute_methods/read.rb', line 39

def read_attribute(attr_name)
  name = attr_name.to_s
  @attributes.fetch(name, nil)