设计模式之组合模式

模式介绍

组合模式，又叫部分整体模式，是用于把一组相似的对象当作一个单一的对象。组合模式依据树形结构来组合对象，用来表示部分以及整体层次。这种类型的设计模式属于结构型模式，它创建了对象组的树形结构。

代码

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


interface Employee {
    public void showEmployeeDetails();
}


class Developer implements Employee {
    private String name;
    private long empId;
    private String position;

    public Developer(long empId, String name, String position) {
        this.empId = empId;
        this.name = name;
        this.position = position;
    }

    @Override
    public void showEmployeeDetails() {
        System.out.println(empId + " " + name + " " + position);
    }
}


class Manager implements Employee {
    private String name;
    private long empId;
    private String position;

    public Manager(long empId, String name, String position) {
        this.empId = empId;
        this.name = name;
        this.position = position;
    }

    @Override
    public void showEmployeeDetails() {
        System.out.println(empId + " " + name + " " + position);
    }
}


class CompanyDirectory implements Employee {
    private List<Employee> employeeList = new ArrayList<Employee>();

    @Override
    public void showEmployeeDetails() {
        for (Employee emp : employeeList) {
            emp.showEmployeeDetails();
        }
    }

    public void addEmployee(Employee emp) {
        employeeList.add(emp);
    }

    public void removeEmployee(Employee emp) {
        employeeList.remove(emp);
    }
}


public class Company {
    public static void main(String[] args) {
        Developer dev1 = new Developer(100, "Lokesh Sharma", "Pro Developer");
        Developer dev2 = new Developer(101, "Vinay Sharma", "Developer");
        CompanyDirectory engDirectory = new CompanyDirectory();
        engDirectory.addEmployee(dev1);
        engDirectory.addEmployee(dev2);

        Manager man1 = new Manager(200, "Kushagra Garg", "SEO Manager");
        Manager man2 = new Manager(201, "Vikram Sharma ", "Kushagra's Manager");
        CompanyDirectory accDirectory = new CompanyDirectory();
        accDirectory.addEmployee(man1);
        accDirectory.addEmployee(man2);

        CompanyDirectory directory = new CompanyDirectory();
        directory.addEmployee(engDirectory);
        directory.addEmployee(accDirectory);
        directory.showEmployeeDetails();
    }
}

输出结果

100 Lokesh Sharma Pro Developer
101 Vinay Sharma Developer
200 Kushagra Garg SEO Manager
201 Vikram Sharma  Kushagra's Manager