linkedlistclass.java

这是有关java的应用 通过事例对java数据结构的链表的应用

package 音像店;
public abstract class LinkedListClass {
    
    protected class LinkedListNode//相当于链表结构体
    {
        DataElement info;
        LinkedListNode link;
    }
    protected LinkedListNode first;
    protected LinkedListNode last;
    protected int count;
    public LinkedListClass()//构造函数
    {  
      first=null;
      last=null;
      count=0;
    }
    public boolean isEmptyList()//判断链表是否为空
    {
        return(first==null);
    }
    public void initializeList()//初始化链表
    {
      first=null;
      last=null;
      count=0;  
    }
    public void print()//打印链表的全体数据
    {
         LinkedListNode current;
         current=first;
         while(current!=null)
         {
             System.out.print(current.info + "");
             current=current.link;
         }
    }
    public int length()//求链表的长度
    {
        return count;
    }
    public DataElement front()//检索链表的最后一个节点
    {
        DataElement temp=first.info.getCopy();
        return temp; 
    }
    public DataElement back()//检索链表的第一个节点
    {
        DataElement temp=last.info.getCopy();
        return temp; 
    }
    public void insertFirst(DataElement newItem)//在链表头插入节点
    {
        LinkedListNode newNode;
        newNode=new LinkedListNode();
        newNode.info=newItem.getCopy();
        newNode.link=first;
        first=newNode;
        if(last==null) last=newNode;
        count++;
    }
    public void insertLast(DataElement newItem)//在链表尾插入节点
    {
        LinkedListNode newNode;
        newNode=new LinkedListNode();
        newNode.info=newItem.getCopy();
        newNode.link=null;
        if(first==null) 
        {
            first=newNode;
            last=newNode;
        }
        else
        {
            last.link=newNode;
            last=newNode;
        }
        count++;
    }
    private void copy(LinkedListClass otherList)//复制链表
    {
        LinkedListNode newNode;
        LinkedListNode current;
        first=null;
        if(otherList.first==null)
        {
            first=null;
            last=null;
            count=0;  
        }
        else
        {
            count=otherList.count;
            current=otherList.first;
            first=new LinkedListNode();
            first.info=current.info.getCopy();
            first.link=null;
            current=current.link;
            while(current!=null)
            {
                newNode=new LinkedListNode();
                newNode.info=current.info.getCopy();
                newNode.link=null;
                last.link=newNode;
                last=newNode;
                current=current.link;
            }
        }
    }
    public LinkedListClass(LinkedListClass otherList)//拷贝构造函数 
    {
        copy(otherList);
    }
    public void copyList(LinkedListClass otherList)//复制链表
    {
        if(this !=otherList) copy(otherList);
    }
    public abstract boolean search(DataElement sreachItem);
    public abstract void deleteNode(DataElement deleteItem);
}