java学习之—链表（3）

/**
 * 使用链表实现队列
 * Create by Administrator
 * 2018/6/19 0019
 * 下午 4:37
 **/
public class Link {

    public long dData;
    public Link next;

    public Link(long d){
        this.dData = d;
    }

    public void displayLink(){
        System.out.print(dData + " ");
    }
}

class FirstLastList{

    private Link first;

    private Link last;

    public FirstLastList(){
        this.first = null;
        this.last = null;
    }

    public boolean isEmpty(){
        return first == null;
    }

    public void insertLast(long dd){
        Link newLink = new Link(dd);
        if(isEmpty()){
            first = newLink;
        }else {
            last.next = newLink;
        }
        last = newLink;
    }

    public long deleteFirst(){
        long temp = first.dData;
        if(first.next == null){
            last = null;
        }
        first = first.next;
        return temp;
    }

    public void displayList(){
        Link current = first;
        while (current != null){
            current.displayLink();
            current = current.next;
        }
        System.out.println("");
    }
}

class LinkQueue{
    private FirstLastList theList;

    public LinkQueue(){
        this.theList = new FirstLastList();
    }
    public boolean isEmpty(){
        return theList.isEmpty();
    }

    public void insert(long j){
        theList.insertLast(j);
    }

    public long remove(){
        return theList.deleteFirst();
    }

    public void displayQueue(){
        System.out.print("Queue (front-->rear): ");
        theList.displayList();
    }

    public static void main(String[] args) {
        LinkQueue linkQueue = new LinkQueue();
        linkQueue.insert(20);
        linkQueue.insert(40);

        linkQueue.displayQueue();

        linkQueue.insert(60);
        linkQueue.insert(80);

        linkQueue.displayQueue();

        linkQueue.remove();
        linkQueue.remove();

        linkQueue.displayQueue();
    }
}