[designmode] composite mode

Basic introduction

1. Portfolio model （Composite Pattern）, Also known as part of the overall model , It creates a tree structure of object groups , Combine objects into a tree structure to represent “ whole - part ” The hierarchy of .

2. Combining patterns combine objects according to a tree structure , Used to represent part and whole level .

3. This type of design pattern belongs to structural pattern .

4. The combination mode makes the access of users to single object and combination object consistent , namely ： Composition allows customers to deal with individual objects and composite objects in a consistent way

1. Look at the display needs of a school department

Write a program to show the structure of a school ：

This is the demand , To show the composition of the school department in a page , There are many colleges in a school , A college has many departments . Pictured ：

2. Display of traditional solutions in schools and departments ( Class diagram )

3. Traditional solutions to the problems existing in the display of schools and departments

1. Think of the college as a subclass of the school , The Department is a subclass of the college , In fact, this is based on the size of the organization

2. In fact, our request is ： Show the composition of the school department in a page , There are many colleges in a school , A college has many departments , So this program , Management operations that cannot be well implemented , Than