// 状态抽象类
public abstract class CourseVideoState {
protected CourseVideoContext courseVideoContext;
public void setCourseVideoContext(CourseVideoContext courseVideoContext) {
this.courseVideoContext = courseVideoContext;
}
public abstract void play();
public abstract void speed();
}
// 上下文
public class CourseVideoContext {
private CourseVideoState state;
public final static PlayState PLAY_STATE = new PlayState();
public final static SpeedState SPEED_STATE = new SpeedState();
public CourseVideoState getState() {
return state;
}
public void setState(CourseVideoState state) {
this.state = state;
this.state.setCourseVideoContext(this);
}
public void play(){
this.state.play();
}
public void speed(){
this.state.speed();
}
}
// 播放状态
public class PlayState extends CourseVideoState {
@Override
public void play() {
System.out.println("正常播放视频");
}
@Override
public void speed() {
super.courseVideoContext.setState(CourseVideoContext.SPEED_STATE);
}
}
// 加速播放状态
public class SpeedState extends CourseVideoState {
@Override
public void play() {
super.courseVideoContext.setState(CourseVideoContext.PLAY_STATE);
}
@Override
public void speed() {
System.out.println("正在加速播放视频");
}
}
// 使用
public class Test {
public static void main(String[] args){
CourseVideoContext context = new CourseVideoContext();
context.setState(new PlayState());
System.out.println("当前状态："+ context.getState().getClass().getSimpleName());
context.speed();
System.out.println("当前状态："+ context.getState().getClass().getSimpleName());
context.play();
System.out.println("当前状态："+ context.getState().getClass().getSimpleName());
}
}
// out put
当前状态：PlayState
当前状态：SpeedState
当前状态：PlayState