Chain of Responsibility

1、这个pattern是非常适合于"pipeline flow of request"的，因此在实现上是需要形成chain structure

2、这个pattern相对容易理解

refactoring.guru Chain of Responsibility

Chain of Responsibility is a behavioral design pattern that lets you pass requests along a chain of handlers. Upon receiving a request, each handler decides either to process the request or to pass it to the next handler in the chain.

NOTE:

1、每个handler有两个option:

a、handle

b、pass to next handler

Problem

Solution

Handlers are lined up one by one, forming a chain.

NOTE:

1、上图是非常形象的

Real-World Analogy

A call to tech support can go through multiple operators.

Structure

Applicability

Relations with Other Patterns

wikipedia Chain of responsibility pattern