The State Pattern

An introduction to the State Pattern: a behavioral design pattern that allows an object to partially change its type at runtime. The state pattern is a subset of the strategy pattern. The state pattern has a variety of uses, not least amongst them helping to encapsulate state changes of NHibernate persistent entities ssince it is usually undesirable to have a persistent entity change its type. The state pattern will also help you avoid brittle switch statements in domain logic.