CODESAMPLE

Bridge - Ruby

Bridge Ruby

The Bridge pattern is a structural design pattern that lets you split an abstraction from its implementation so that objects can have different implementations. This is useful when there is a need to avoid a hard coupling between an abstraction and its implementation, allowing both to vary independently.

The code demonstrates a Device abstraction and two concrete implementations: Radio and TV. A RemoteControl acts as the ‘remote’ (the abstraction) and can operate on either implementation without knowing the specifics. This separation is achieved by the RemoteControl holding an instance of the Device interface. Ruby’s duck typing and flexible nature make this pattern a natural fit, as the RemoteControl doesn’t enforce a strict class hierarchy, but relies on the Device objects responding to the necessary methods.

# Device interface
module Device
  def button_pressed
    raise NotImplementedError
  end

  def get_volume
    raise NotImplementedError
  end

  def set_volume(volume)
    raise NotImplementedError
  end
end

# Concrete Implementations
class Radio
  include Device

  def initialize
    @volume = 3
  end

  def button_pressed
    puts "Radio is playing!"
  end

  def get_volume
    @volume
  end

  def set_volume(volume)
    @volume = volume
  end
end

class TV
  include Device

  def initialize
    @volume = 5
    @channel = 1
  end

  def button_pressed
    puts "TV is displaying!"
  end

  def get_volume
    @volume
  end

  def set_volume(volume)
    @volume = volume
  end
end

# Abstraction
class RemoteControl
  def initialize(device)
    @device = device
  end

  def button_pressed
    @device.button_pressed
  end

  def volume_up
    @device.set_volume(@device.get_volume + 1)
  end

  def volume_down
    @device.set_volume(@device.get_volume - 1)
  end

  def display_volume
    puts "Current volume: #{@device.get_volume}"
  end
end

# Usage
radio = Radio.new
tv = TV.new

remote_radio = RemoteControl.new(radio)
remote_tv = RemoteControl.new(tv)

remote_radio.button_pressed
remote_radio.volume_up
remote_radio.display_volume

remote_tv.button_pressed
remote_tv.volume_down
remote_tv.display_volume