list.java

一个游戏中物品的类

public class List{
  private Link head;
  private Link tail;
  private Link curr;
  public List(){
    setup();
  }
  private void setup() {
    tail=head=curr=new Link(null);
  }
  public void clear()
  {
    head.setNext(null);
    curr=tail=head;
  }

  public Link getCur()
  {
    return curr;
  }

  public void insert(Object obj)
  {
    curr.setNext(new Link(obj,curr.next()));
    if(tail==curr)
    {
      tail=curr.next();
    }
  }

  public void insert(int pos,Object obj)
  {
    setPos(pos);
    insert(obj);
  }

  public void append(Object it)
  {
    tail.setNext(new Link(it,null));
    tail=tail.next();
  }

  public void remove()
  {
    if(tail==curr.next())
    {
      tail=curr;
    }
    curr.setNext(curr.next().next());
  }

  public void setFirst()
  {
    curr=head;
  }

  public void next()
  {
    if(curr!=null)
    {
      curr=curr.next();
    }
  }

  public int length()
  {
    int cnt=0;
    for(Link temp=head.next();temp!=null;temp=temp.next())
    {
      cnt++;
    }
    return cnt;
  }

  public void setPos(int pos)
  {
    curr=head;
    for(int i=0;(curr!=null) && (i<pos);i++)
    {
      curr=curr.next();
    }
  }

  public void setValue(Object obj)
  {
    if(curr!=null )
    {
      curr.setElement(obj);
    }
  }

  public Object curValue()
  {
    if(curr!=null )
      return curr.element();
    return null;
  }

  public boolean isEmpty()
  {
    return head.next()==null;
  }
}