list.java

模拟操作系统的进程调用

import java.awt.*;
import java.awt.event.*;
import asd.Inform;


class ListNode {
    Inform data;
    ListNode next;

    ListNode( Inform idata , ListNode nextNode )
    {
       data = idata;
       next = nextNode;
      
    }
}      
public class List {
	private ListNode head;
	private ListNode tail;
	private String name;
	
	public List( String s )
	{
		name = s;
		head = tail = null;
	}
	
	public List()
	{
		this( "List" );
	}
	
    public void insertAtFront( Inform insertItem )
    {
    	if ( isEmpty() )
           head = tail = new ListNode( insertItem , null );
        else
           head = new 	ListNode( insertItem ,head );
              
     }
     
    public void insertAtBack ( Inform insertItem ) 
    {
    	if ( isEmpty() )
           head = tail = new ListNode( insertItem , null );
        else
           tail = tail.next = new ListNode( insertItem ,null );
           
    }
    
    public Inform removeFromFront() 
    {
    	Inform removeItem = null;
    	
           removeItem = head.data;
         
        if ( head.equals(tail) )    	
           head = tail = null;
        else
           head = head.next;
        return removeItem;
     }
     
     
     public Inform Remove ( Inform item )
     {
     	Inform removeItem = null;
     	if( head.equals(tail ) )
     	   head = tail = null;
     	else{
     		ListNode current = head;
     		while (current.data != item )
     	     	current = current.next;
     	     	removeItem = current.data;
     	     }
     	     	
     	    return removeItem;
     	      
     }
     
     public boolean isEmpty()
     { return head == null;}
}