new

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 35
        def initialize(app, constraints, strategy)
          # Unwrap Constraints objects. I don't actually think it's possible to pass a
          # Constraints object to this constructor, but there were multiple places that
          # kept testing children of this object. I **think** they were just being
          # defensive, but I have no idea.
          if app.is_a?(self.class)
            constraints += app.constraints
            app = app.app
          end

          @strategy = strategy

          @app, @constraints, = app, constraints
        end