观察者模式:
对象之间多对一依赖的一种设计方案,被依赖对象为Subject(一),依赖对象为Observer(多),Subject通知Observer变化
直接代码:
package com.wz.twoObserver;
public interface Subject {
public void add(Observer student);
public void del(Observer student);
public void mNotify();
}
package com.wz.twoObserver;
public interface Observer {
public void update(String name, String sex, String subject);
}
package com.wz.twoObserver;
import java.util.ArrayList;
/**
* 教师类
*
* @author Administrator
* @create 2018-04-18 11:50
*/
public class Teacher implements Subject{
private String name;
private String sex;
// 学科
private String subject;
private ArrayList<Observer> studentList;
// 记住要将集合初始化
public Teacher() {
this.studentList = new ArrayList<>();
}
public String getName() {
return name;
}
public String getSex() {
return sex;
}
public String getSubject() {
return subject;
}
public void teacherUpdate(){
mNotify();
}
public void setTeacher(String name, String sex, String subject){
this.name = name;
this.sex = sex;
this.subject = subject;
teacherUpdate();
}
@Override
public void add(Observer student) {
studentList.add(student);
}
@Override
public void del(Observer student) {
studentList.remove(student);
}
@Override
public void mNotify() {
for (int i = 0; i < studentList.size() ; i++) {
studentList.get(i).update(name,sex,subject);
}
}
}
package com.wz.twoObserver;
/**
* 学生类
*
* @author Administrator
* @create 2018-04-18 11:53
*/
public class Student implements Observer{
private String name;
private String sex;
// 学科
private String subject;
@Override
public void update(String name, String sex, String subject){
this.name = name;
this.sex = sex;
this.subject = subject;
display();
}
public void display(){
System.out.println("教师姓名:" + name);
System.out.println("教师的性别:" + sex);
System.out.println("教师的学科:" + subject);
System.out.println("=================================");
}
}
package com.wz.twoObserver;
/**
* 学生类
*
* @author Administrator
* @create 2018-04-18 11:53
*/
public class Student1 implements Observer{
private String name;
private String sex;
// 学科
private String subject;
@Override
public void update(String name, String sex, String subject){
this.name = name;
this.sex = sex;
this.subject = subject;
display();
}
public void display(){
System.out.println("教师姓名:" + name);
System.out.println("教师的性别:" + sex);
System.out.println("教师的学科:" + subject);
System.out.println("=================================");
}
}
package com.wz.twoObserver;
/**
* 学生类
*
* @author Administrator
* @create 2018-04-18 11:53
*/
public class Student2 implements Observer{
private String name;
private String sex;
// 学科
private String subject;
@Override
public void update(String name, String sex, String subject){
this.name = name;
this.sex = sex;
this.subject = subject;
display();
}
public void display(){
System.out.println("教师姓名:" + name);
System.out.println("教师的性别:" + sex);
System.out.println("教师的学科:" + subject);
System.out.println("=================================");
}
}
package com.wz.twoObserver;
/**
* 测试类
*
* @author Administrator
* @create 2018-04-18 12:12
*/
public class TestMain {
public static void main(String[] args) {
Teacher t1 = new Teacher();
Student s = new Student();;
Student1 s1 = new Student1();;
Student2 s2 = new Student2();
t1.add(s);
t1.add(s1);
t1.add(s2);
t1.setTeacher("郑爽","女","舞蹈");
System.out.println("======================================");
t1.del(s);
t1.setTeacher("杨洋","男","演技");
}
}
自我感觉这个模式不是特别的理解,看的视频是以天气预报为例,我这以教师和学生为例,开始郑爽老师有3个学生,后来换成杨洋老师了,学生s就退学了,就剩下学生s1和s2的
