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java - 使用匿名类实例化了一个抽象类之后,如何重写其中的抽象方法并调用?

public abstract class Rhythm {

    /**
     * @return duration between {@linkplain Note} in milliseconds
     */
    public abstract long getDuration();

    public void perform() {
        long duration = getDuration();
        try {
            Thread.sleep(duration);
        } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
            throw new RuntimeException(ie);
        }
    }
}

--------------------------------------------------------------------

@Override public void play(Rhythm rhythm, Note note, NoteCallback noteCallback){
    rhythm.getDuration();//想在这里重写getDuration方法,如何做到?
    rhythm.perform();
    note.getNoteValue();
    noteCallback.notePlayed(note);
}

--------------------------------------------------------------------

//重写成如下形式
  @Override public long getDuration(){
      return (expectedMs);
   }

代码附上。在play() 方法中如何直接重写Rhythm类中的抽象方法getDuration()呢? 创建rhythm对象是可以用匿名类的方法实例化的,那是实例化之后 想调用一个重写的getDuration()方法,有什么办法么?在不引入子类继承的前提下。

伊谢尔伦伊谢尔伦2802 天前600

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  • 怪我咯

    怪我咯2017-04-18 10:49:54

    java不能怎麼做,但能用內部類變相的實現這個需求

    public abstract class Rhythm {
    
        /**
         * @return duration between {@linkplain Note} in milliseconds
         */
        public abstract long getDuration();
        
        public abstract class InnderClass {
            public abstract long getDuration();
        }
    
        private InnderClass innderClass;
    
        public Rhythm() {
            innderClass = new InnderClass() {
                @Override
                public long getDuration() {
                    return Rhythm.this.getDuration();
                }
            };
        }
    
        public void setInnderClass(InnderClass innderClass) {
            this.innderClass = innderClass;
        }
    
        public void perform() {
            long duration = innderClass.getDuration();
            try {
                Thread.sleep(duration);
            } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
                throw new RuntimeException(ie);
            }
        }
    }
    @Override public void play(Rhythm rhythm, Note note, NoteCallback noteCallback){
            //rhythm.getDuration();//想在这里重写getDuration方法,如何做到?
            rhythm.setInnderClass(rhythm.new InnderClass() {
                
                @Override
                public long getDuration() {
                    // TODO 把实现放到这里
                    return 0;
                }
            });
            rhythm.perform();
            note.getNoteValue();
            noteCallback.notePlayed(note);
        }

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    0
  • 怪我咯

    怪我咯2017-04-18 10:49:54

    做不了吧,如果能做Java豈不是動態語言了?

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    0
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