八、组合模式

1 应用场景？

　　表示整体和部分关系时，比如公司分公司以及部门之间的层次结构关系。

2 优点？

　　实现被组合的对象之间的扩展。比如总公司下可以添加各个分公司，分公司之间是松耦合的，可以方便的扩展出更多的分公司。

3 demo?

package com.biao.combine.again;

import java.util.ArrayList;
import java.util.List;

public class Combine {
    public static void main(String[] args) {
        Company company = new ConcreteCompany("bs总公司");
        Company company1 = new ConcreteCompany("bs北京分公司");
        Company company2 = new ConcreteCompany("bs上海分公司");
        FinanceDepartment finance = new FinanceDepartment("bs总财务部");
        FinanceDepartment finance2 = new FinanceDepartment("bs上海财务部");
        FinanceDepartment finance1 = new FinanceDepartment("bs北京财务部");
        
        company.add(company1);
        company.add(company2);
        company.add(finance);
        
        finance.add(finance1);
        finance.add(finance2);
        
        
        company.show(2);
//        finance.show(4);
    }
    
}
abstract class Company{
    public String name;
    abstract void add(Company company);
    abstract void remove(Company company);
    abstract void show(int detpy);
}

class ConcreteCompany extends Company{
    private List<Company> list = new ArrayList<Company>();
    public ConcreteCompany(String name) {
        // TODO Auto-generated constructor stub
        this.name = name;
    }
    @Override
    void add(Company company) {
        // TODO Auto-generated method stub
        list.add(company);
    }

    @Override
    void remove(Company company) {
        // TODO Auto-generated method stub
        list.remove(company);
    }

    @Override
    void show(int detpy) {
        // TODO Auto-generated method stub
        StringBuilder sb = new StringBuilder();
        for(int i=0;i<detpy;i++){
            sb.append("-");
        }
        System.out.println(new String(sb)+name);
        for (Company company : list) {
            company.show(detpy+2);
        }
    }
    
}

class HRDepartment extends Company{
    List<Company>list = new ArrayList<>();
    @Override
    void add(Company company) {
        // TODO Auto-generated method stub
        list.add(company);
    }

    @Override
    void remove(Company company) {
        // TODO Auto-generated method stub
        list.remove(company);
    }

    @Override
    void show(int detpy) {
        // TODO Auto-generated method stub
        StringBuffer sb = new StringBuffer();
        for(int i=0;i<detpy;i++){
            sb.append("-");
        }
        System.out.println(new String(sb)+name);
        for (Company company : list) {
            company.show(detpy+2);
        }
    }
    
}
class FinanceDepartment extends Company{
    List<Company>list = new ArrayList<>();
    
    public FinanceDepartment(String name) {
        // TODO Auto-generated constructor stub
        this.name = name;
    }
    @Override
    void add(Company company) {
        // TODO Auto-generated method stub
        list.add(company);
    }
    
    @Override
    void remove(Company company) {
        // TODO Auto-generated method stub
        list.remove(company);
    }
    
    @Override
    void show(int detpy) {
        // TODO Auto-generated method stub
        StringBuffer sb = new StringBuffer();
        for(int i=0;i<detpy;i++){
            sb.append("-");
        }
        System.out.println(new String(sb)+name);
        for (Company company : list) {
            company.show(detpy+2);
        }
    }
    
}