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The bridge pattern in Ruby is a design pattern used in software engineering. The bridge pattern is useful for situations where you want to:
– Decouple an abstraction from its implementation so that they can vary independently.
– Create a new abstraction similar to an existing one but with different implementations.
– Keep an abstraction and its implementation independent so they can be developed separately.
The bridge pattern is useful in plain English when creating an abstraction that can work with different implementations.
A good example of this is an abstract class that can work with different concrete classes.
Here’s a simple example of the bridge pattern in action:
class Shape
def initialize(renderer)
@renderer = renderer
end
end
class Triangle < Shape
def to_s
"triangle"
end
end
class Square < Shape
def to_s
"square"
end
end
class RasterRenderer
def render(shape)
puts "Drawing #{shape.to_s} as pixels"
end
end
class VectorRenderer
def render(shape)
puts "Drawing #{shape.to_s} as lines"
end
end
raster = RasterRenderer.new
vector = VectorRenderer.new
triangle = Triangle.new(raster)
square = Square.new(vector)
puts triangle
# Drawing triangle as pixels
puts square
# Drawing square as lines
In this example, we have two abstractions (Shape and Renderer) and two implementations (RasterRenderer and VectorRenderer).
The concrete classes (Triangle and Square) inherit from the Shape abstraction, and they take a Renderer object in their constructor.
The Renderer object is responsible for rendering the shape.
This gives us a lot of flexibility because we can create new shapes (like a Pentagon class), and they will work with the existing Renderer classes.
We can also create new Renderer classes (like a RayTracer class), which will work with the existing Shape classes.
Summary
In this article, you’ve learned about the bridge pattern and how to implement it in Ruby.
The bridge pattern is useful for situations where you want to:
– Decouple an abstraction from its implementation so that they can vary independently.
– Create a new abstraction similar to an existing one but with different implementations.
– Keep an abstraction and its implementation independent so they can be developed separately.