package 链表实践;public class Link {    public long dData;    public Link next;        public Link(long dd)    {        dData = dd;    }        public void displayLink()    {        System.out.print(dData+"  ");    }    }--------------------------------------------------------------------------package 链表实践;public class SortedList {    private Link first;    public SortedList()    {        first = null;    }        //判断是不是为空    public boolean isEmpty()    {        if(first == null){            return true;        }else{            return false;        }    }        //插入链表的方法的实现    public void insert(long key)    {        Link newLink = new Link(key);        Link previous = null;//从first开始        Link current = first;        while(current != null && key > current.dData)        {            previous = current;            current = current.next;        }                if(previous == null)        {            first = newLink;        }else{            previous.next = newLink;        }        newLink.next = current;            }        public Link remove()    {        Link temp = first;        first = first.next;        return temp;    }        public void displayList()    {         System.out.print("List (first-->last): ");              Link current = first; // start at beginning of list              while (current != null) // until end of list,              {                  current.displayLink(); // print data                  current = current.next; // move to next link              }              System.out.println("");      }        }---------------------------------------------------------------package 链表实践;public class PriorityQ {      private SortedList sortedList;                public PriorityQ() {              sortedList = new SortedList();          }                public void insert(long item) {              sortedList.insert(item);          }                public long remove() {              return sortedList.remove().dData;          }                public boolean isEmpty() {              return sortedList.isEmpty();          }                public void display() {              sortedList.displayList();          }  }