Class: Interfaces::Interface

Inherits:
Object
  • Object
show all
Defined in:
lib/interfaces/interface.rb

Overview

Interface is meant to be used as a base class for the definition of Interfaces

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Interface

allow interfaces to be instantiated directly by passing in values for each of the abstract methods



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# File 'lib/interfaces/interface.rb', line 60

def initialize(opts = {})
  opts.each_pair do |key, value|

    # only allow initializers for abstract methods
    unless self.class.abstract_methods.include?(key.to_sym) || self.class.optional_methods.include?(key.to_sym)
      raise InterfaceError, "Attempted to assign value to method '#{key}' which is not an abstract or optional method of #{self.class}"
    end

    if value.is_a?(Proc)
      # if the value is a proc then the abstract method
      # override should call that proc
      self.define_singleton_method(key, &value)
    else
      # if the value is not a proc, then the abstract
      # method override should just return the value
      self.define_singleton_method(key) { value }
    end
  end
end

Class Method Details

.abstract(*methods) ⇒ Object

Define methods as asbtract



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# File 'lib/interfaces/interface.rb', line 7

def self.abstract(*methods)
  @abstract_methods ||= Set.new
  methods.each do |method|
    # the default implmentation of an abstract method is to
    # raise the AbstractMethodInvokedError exception
    define_method(method) do
      raise AbstractMethodInvokedError, "Abstract method #{method} called"
    end
    @abstract_methods << method.to_sym
  end
end

.abstract? ⇒ Boolean

True if a class has abstract methods

Returns:

  • (Boolean) 


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# File 'lib/interfaces/interface.rb', line 33

def self.abstract?
  !abstract_methods.empty?
end

.abstract_methods ⇒ Object

Lists all abstract methods of a class



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# File 'lib/interfaces/interface.rb', line 20

def self.abstract_methods
  if self == Interface
    []
  else
    # determine which methods of superclass are still undefined
    nonoverrided_superclass_abtract_methods = superclass.abstract_methods.reject do |m|
      self.instance_methods.include?(m) && self.instance_method(m).owner == self
    end
    ( (@abstract_methods || Set.new) + nonoverrided_superclass_abtract_methods ).to_a
  end
end

.optional(*methods) ⇒ Object

Define methods as optional



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# File 'lib/interfaces/interface.rb', line 47

def self.optional(*methods)
  @optional_methods ||= Set.new
  methods.each do |method|
    # the default implmentation of an optional method is to return nil
    define_method(method) do
      nil
    end
    @optional_methods << method.to_sym
  end
end

.optional_methods ⇒ Object

List all optional methods of a class



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# File 'lib/interfaces/interface.rb', line 38

def self.optional_methods
  if self == Interface
    []
  else
    ( (@optional_methods || Set.new) + superclass.optional_methods ).to_a
  end
end