Class: Aws::Templates::Utils::Parametrized::Getter

Inherits:
Object
  • Object
show all
Defined in:
lib/aws/templates/utils/parametrized/getter.rb,
lib/aws/templates/utils/parametrized/getter/dsl.rb,
lib/aws/templates/utils/parametrized/getter/path.rb,
lib/aws/templates/utils/parametrized/getter/as_is.rb,
lib/aws/templates/utils/parametrized/getter/value.rb,
lib/aws/templates/utils/parametrized/getter/one_of.rb,
lib/aws/templates/utils/parametrized/getter/as_instance_variable.rb

Overview

Getter functor class

A getter is a Proc without parameters and it is expected to return a value. Since the proc is to be executed in instance context the value can be calculated based on other methods or extracted from options attrribute

The class implements functor pattern through to_proc method and closure. Essentially, all getters can be used everywhere where a block is expected.

It provides protected method get which should be overriden in all concrete getter classes.

Direct Known Subclasses

AsInstanceVariable, AsIs, OneOf, Path, Value

Defined Under Namespace

Modules: Dsl Classes: AsInstanceVariable, AsIs, OneOf, Path, Value

Instance Method Summary collapse

Instance Method Details

#get_wrapper(parameter, instance) ⇒ Object

Wraps getter-dependent method

It wraps constraint-dependent “get” method into a rescue block to standardize exception type and information provided by failed value calculation

  • parameter - the Parameter object which the getter is executed for

  • instance - the instance value is taken from



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# File 'lib/aws/templates/utils/parametrized/getter.rb', line 49

def get_wrapper(parameter, instance)
  get(parameter, instance)
rescue StandardError
  raise Templates::Exception::NestedParameterException.new(parameter)
end

#to_proc ⇒ Object

Creates closure with getter invocation

It’s an interface method required for Getter to expose functor properties. It encloses invocation of Getter get_wrapper method into a closure. The closure itself is executed in the context of Parametrized instance which provides proper set “self” variable.

The closure itself accepts 1 parameters

  • parameter - the Parameter object which the getter is executed for

…where instance is assumed from self



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# File 'lib/aws/templates/utils/parametrized/getter.rb', line 33

def to_proc
  getter = self

  lambda do |parameter|
    getter.get_wrapper(parameter, self)
  end
end