标签：att 场景 bst 状态改变 暂停 dstat abstract 代码 视频
1.定义：允许一个对象在其内部状态改变时，改变它的行为。
2.类型：行为型
3.适用场景：一个对象存在多个状态(不同状态下行为不同)，且状态可相互转换。
4.优点：将不同的状态隔离，把各种状态的转换逻辑，分布到State的子类中，减少相互间依赖；
增加新的状态非常简单。
5.缺点：状态多的业务场景导致类数目增加，系统变得复杂
6.相关设计模式：享元模式
7.实例目录package
8.实例UML类图
9.代码
1 package com.geely.design.pattern.behavioral.state; 2 3 public abstract class CourseVideoState { 4 protected CourseVideoContext courseVideoContext; 5 6 public void setCourseVideoContext(CourseVideoContext courseVideoContext) { 7 this.courseVideoContext = courseVideoContext; 8 } 9 10 public abstract void play(); 11 public abstract void speed(); 12 public abstract void pause(); 13 public abstract void stop(); 14 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class PlayState extends CourseVideoState { 4 @Override 5 public void play() { 6 System.out.println("正常播放课程视频状态"); 7 } 8 9 @Override 10 public void speed() { 11 super.courseVideoContext.setCourseVideoState(CourseVideoContext.SPEED_STATE); 12 } 13 14 @Override 15 public void pause() { 16 super.courseVideoContext.setCourseVideoState(CourseVideoContext.PAUSE_STATE); 17 } 18 19 @Override 20 public void stop() { 21 super.courseVideoContext.setCourseVideoState(CourseVideoContext.STOP_STATE); 22 } 23 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class SpeedState extends CourseVideoState { 4 @Override 5 public void play() { 6 super.courseVideoContext.setCourseVideoState(CourseVideoContext.PLAY_STATE); 7 } 8 9 @Override 10 public void speed() { 11 System.out.println("快进播放课程视频状态"); 12 } 13 14 @Override 15 public void pause() { 16 super.courseVideoContext.setCourseVideoState(CourseVideoContext.PAUSE_STATE); 17 } 18 19 @Override 20 public void stop() { 21 super.courseVideoContext.setCourseVideoState(CourseVideoContext.STOP_STATE); 22 } 23 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class PauseState extends CourseVideoState { 4 @Override 5 public void play() { 6 super.courseVideoContext.setCourseVideoState(CourseVideoContext.PLAY_STATE); 7 } 8 9 @Override 10 public void speed() { 11 super.courseVideoContext.setCourseVideoState(CourseVideoContext.SPEED_STATE); 12 } 13 14 @Override 15 public void pause() { 16 System.out.println("暂停播放课程视频状态"); 17 } 18 19 @Override 20 public void stop() { 21 super.courseVideoContext.setCourseVideoState(CourseVideoContext.STOP_STATE); 22 } 23 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class StopState extends CourseVideoState { 4 @Override 5 public void play() { 6 super.courseVideoContext.setCourseVideoState(CourseVideoContext.PLAY_STATE); 7 } 8 9 @Override 10 public void speed() { 11 System.out.println("ERROR 停止状态不能快进！！"); 12 } 13 14 @Override 15 public void pause() { 16 System.out.println("ERROR 停止状态不能暂停！！"); 17 } 18 19 @Override 20 public void stop() { 21 System.out.println("停止播放课程视频状态"); 22 } 23 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class CourseVideoContext { 4 private CourseVideoState courseVideoState; 5 6 public final static PlayState PLAY_STATE = new PlayState(); 7 public final static SpeedState SPEED_STATE = new SpeedState(); 8 public final static PauseState PAUSE_STATE = new PauseState(); 9 public final static StopState STOP_STATE = new StopState(); 10 11 public CourseVideoState getCourseVideoState() { 12 return courseVideoState; 13 } 14 15 public void setCourseVideoState(CourseVideoState courseVideoState) { 16 this.courseVideoState = courseVideoState; 17 this.courseVideoState.setCourseVideoContext(this); 18 } 19 20 public void play(){ 21 this.courseVideoState.play(); 22 } 23 public void speed(){ 24 this.courseVideoState.speed(); 25 } 26 public void stop(){ 27 this.courseVideoState.stop(); 28 } 29 public void pause(){ 30 this.courseVideoState.pause(); 31 } 32 }
1 package com.geely.design.pattern.behavioral.state; 2 3 public class Test { 4 public static void main(String[] args) { 5 CourseVideoContext courseVideoContext = new CourseVideoContext(); 6 courseVideoContext.setCourseVideoState(new PlayState()); 7 8 System.out.println("当前状态：" + courseVideoContext.getCourseVideoState().getClass().getSimpleName()); 9 10 courseVideoContext.pause(); 11 System.out.println("当前状态：" + courseVideoContext.getCourseVideoState().getClass().getSimpleName()); 12 13 courseVideoContext.speed(); 14 System.out.println("当前状态：" + courseVideoContext.getCourseVideoState().getClass().getSimpleName()); 15 16 courseVideoContext.stop(); 17 System.out.println("当前状态：" + courseVideoContext.getCourseVideoState().getClass().getSimpleName()); 18 19 courseVideoContext.speed(); 20 } 21 }
标签：att 场景 bst 状态改变 暂停 dstat abstract 代码 视频
原文地址：https://www.cnblogs.com/linbq1911/p/10231137.html
