链表继承java

Question

public class Link {
       public static Link LAST = new Link(-1);
       public Link next;
       public int myId;
       public Link() {
              this(10);
}
       public Link(Link next) {
              this(20);
              this.next = next;
}
      protected Link(boolean b) {
              this(99);
}
      private Link(int myId) {
              this.myId = myId;
}
@Override
      public String toString() {
             return "Link #" + myId;
}
}
       public class DataLink<T> extends Link {
       private T value;
       public DataLink(T value) {
              this(value, new Link(false));
}
       public DataLink(T value, Link parent) {
               super(parent);
               this.value = value;
}
      @Override
      public String toString() {
            return super.toString() + " (" + value.toString() +")";
}
}
       public class Main {
       public static void main(String[] args) {
************************
}
}

代替 ************************

system . out。println(新DataLink<>(新的链接()). next),

打印Link # 99，它是如何到达protected Link(Boolean b)的?

Answer 1

您可以使用任何JAVA IDE来跟踪这些步骤

new DataLink<>(new Link()).next

获取DataLink的父类( LINK )的NEXT LINK对象，因为DataLink类没有NEXT对象。

这是步骤

1.new DataLink<>(new Link())
2.this(value, new Link(false));  
    3.protected Link(boolean b) {    //from new Link(false)
          this(99); 
    4. this.myId = myId;  // myId = 99, from this(99)
5.super(parent); //calling public Link(Link next)
6.this.next = next; //next = link object with myId=99

所以当你调用new DataLink<>(new Link())时。下一个, 。next将在父类中调用next对象，该对象将打印Link # 99