java - 如何实现原型(prototype)模式？

Question

原型(prototype)模式的目标是通过降低创建成本来克隆一个对象。这是一个例子:

class Complex {
    int[] nums = {1,2,3,4,5};
    public Complex clone() {
        return new Complex();//this line create a new object, so is it violate the objective             of prototype ?//
    }
}

class Test2 {
   Complex c1 = new Complex();
   Complex makeCopy() {
      return (Complex)c1.clone();// Is it actually create a new object ? based on the clone method in Complex class? //
   }
   public static void main(String[] args) {
       Test2 tp = new Test2();
       Complex c2 = tp.makeCopy();
   }
}

我认为是为了深拷贝。那么，有人可以帮我解决这个问题吗？？？

Answer 1

首先，要让它正常工作，您的 Complex 类需要实现 Cloneable标记接口(interface)向 Object.clone() 方法指示该方法制作该类实例的字段对字段副本是合法的。然后你需要覆盖 Object.clone() 方法来指定复制行为:

public Complex clone(){
    Complex clone = (Complex)super.clone();
    clone.nums = this.nums;
    return clone;
}