Painting the chairs with the Bridge pattern

The last pattern we need to complete our wheelchair project is the Bridge pattern. Remember, the Bridge pattern is used when you have two related systems of complex classes. The bridge allows you to join the classes using composition. It gives you the benefit of being able to vary the complexity and maintain these complicated classes independently. Kitty and Phoebe used this system to add the ability to create custom paint jobs for their bicycles. They did this late in the game though, and the changes they had to make to accommodate those changes were problematic. They had to violate the open-closed principle.

This time, with experience behind them, they can integrate the Bridge pattern for painting wheelchairs early in the implementation. The ability to specify colors for wheelchairs will be a big differentiator for Bumble Bikes since most manufacturers only sell black and gray chairs. This is fine for the loaner chair at your local hospital...