Pro Objective-C Design Patterns for iOS

Chapter 17. Chain of Responsibility

No one can know everything, so there is a saying that "two brains are better than one." If it's true, then more brains chained together will be even better. Everybody knows a little bit of something and can unite together to form a powerful entity. It's pretty much like families helping each other in the same neighborhood or collaborations among team members on projects in an organization. Every unit in a chain of brains can contribute to tackling problems. If a unit of the chain doesn't know how to handle a problem, then it will pass the problem along the chain and somebody may be able to handle it. Or sometimes, the problem may still be passed along even though there is a unit that knows how to handle it. ...