Java设计模式：（1）设计模式七大设计原则-迪米特法则

public class Demeter {
    public static void main(String[] args) {
        System.out.println("");
        SchoolManager schoolManager = new SchoolManager();
        schoolManager.printAllEmployee(new CollegeManager());
    }
}

class Employee{
    private String id;
    public void setId(String id){
        this.id = id;
    }

    public String getId(){
        return id;
    }
}

class CollegeEmployee{
    private String id;
    public void setId(String id){
        this.id = id;
    }
    public String getId(){
        return id;
    }
}

class CollegeManager{
    public List<CollegeEmployee> getAllEmployee(){
        List<CollegeEmployee> list = new ArrayList<>();
        for(int i = 0; i < 10; i++){
            CollegeEmployee emp = new CollegeEmployee();
            emp.setId("CollegeEmployee" + i);
            list.add(emp);
        }
    return list;
    }

    public void printEmployee(){
        List<CollegeEmployee> list = getAllEmployee();
        for(CollegeEmployee e: list){
            System.out.println(e.getId());
        }
    }
}

class SchoolManager{
    public List<Employee> getAllEmployee(){
        List<Employee> list = new ArrayList<>();
        for(int i = 0;i < 5;i++){
            Employee emp = new Employee();
            emp.setId("Employee" + i);
            list.add(emp);
        }
        return list;
    }

    void printAllEmployee(CollegeManager sub){
        sub.printEmployee();
        List<Employee> list2 = this.getAllEmployee();
        for(Employee e:list2){
            System.out.println(e.getId());
        }
    }
}

// 运行结果
CollegeEmployee0
CollegeEmployee1
CollegeEmployee2
CollegeEmployee3
CollegeEmployee4
CollegeEmployee5
CollegeEmployee6
CollegeEmployee7
CollegeEmployee8
CollegeEmployee9
Employee0
Employee1
Employee2
Employee3
Employee4