The Bridge Pattern makes a distinction between an abstraction and an implementation in such a way that the two can vary independently. I will use the example from Patterns in Java, Volume 1: A Catalog of Reusable Design Patterns Illustrated with UML, Second Edition You need to provide classes that access physical sensors such as … Read more
Semantics. From wikipedia: The UML class diagram for the Strategy pattern is the same as the diagram for the Bridge pattern. However, these two design patterns aren’t the same in their intent. While the Strategy pattern is meant for behavior, the Bridge pattern is meant for structure. The coupling between the context and the strategies … Read more
“Adapter makes things work after they’re designed; Bridge makes them work before they are. [GoF, p219]” Effectively, the Adapter pattern is useful when you have existing code, be it third party, or in-house, but out of your control, or otherwise not changeable to quite meet the interface you need it to. For instance, we have … Read more
There’s a combination of Federico’s and John’s answers. When: —-Shape— / \ Rectangle Circle / \ / \ BlueRectangle RedRectangle BlueCircle RedCircle Refactor to: —-Shape— Color / \ / \ Rectangle(Color) Circle(Color) Blue Red
Proxy, Decorator, Adapter, and Bridge are all variations on “wrapping” a class. But their uses are different. Proxy could be used when you want to lazy-instantiate an object, or hide the fact that you’re calling a remote service, or control access to the object. Decorator is also called “Smart Proxy.” This is used when you … Read more