Musical Performance

This is an example of a Java design pattern called a Strategy Pattern in Ruby. This is also sample code from a Learn.co Study group on 01/10/2017.

A possible anti-pattern

It may be a good idea to explicitly set a classes behavior at initialization. In the following example Drummer has its behaviors set at initializaiton and the Singer has the behavior set by overriding the initialize from it's parent class with default behavior.

module MusicalPerformance
  def self.run
    drummer = Drummer.new(DrumBehavior, CannotDanceBehavior)
    singer = Singer.new
  end
end

The idea of overriding the initialize to set a default behavior may be considered an anti pattern. It can be argued that it's a good idea to set behavior explicitly at initialization and anything else is an anti pattern. So the example we use for Singer should be considered a possible anti-pattern and needs to be used with extreme prejudice.

class Singer < Musician
  def initialize(instrument_behavior=nil)
    @instrument_behavior = instrument_behavior || VocalBehavior
    @dance_behavior = CanDanceBehavior
  end

  def display
    puts "I love to sing"
  end
end

This is being left in the code as an example because it's worth noting that this is an option. Use your best judgement.