In the previous chapter, we've already talked about some of the behavioral design patterns. We'll be continuing with more patterns in this category in this chapter, including: Strategy Pattern, State Pattern, Template Method Pattern, Observer Pattern, and Visitor Pattern.
Many of these patterns share the same idea: unify the shape and vary the details. Here is a quick overview:
Strategy Pattern and Template Pattern: Defines the same outline of algorithms
State Pattern: Provides different behavior for objects in different states with the same interface
Observer Pattern: Provides a unified process of handling subject changes and notifying observers
Visitor Pattern: Does similar jobs as Strategy Pattern sometimes, but avoids an over complex interface that might be required for Strategy Pattern to handle objects in many different types
Patterns that will be discussed in this chapter could be applied in different scopes just as many patterns in...