About Alexey Zvolinskiy
This article will be about State design pattern. It is one of behavioral design patterns. You don’t need to know many theory to understand the main concepts of the pattern. The post will be break in several parts where I will provide information about situations where the pattern need to be applied, cons and pros which it has and an example of usage.
Sometimes you need to change a behavior of object when its internal state changes. The State design pattern allows to do this. You can obtain this by creation of separate classes which represent different states and functionality. Of Course these classes have to be inherited from one abstract class or implement one interface.
The State design pattern can be used when we need to change state of object at runtime by inputting in it different subclasses of some State base class. This circumstance is advantage and disadvantage in the same time, because we have a clear separate State classes with some logic and from the other hand the number of classes grows up.
Source : http://www.javacodegeeks.com/2013/07/design-patterns-state.html
