Dear,
Just refer this source.
I modify a little bir for your request.
The orginal source is from "Java Examples In A Nutshell" 2nd edition from
O'REILLY.
I think that book will give you more idea.
Thanks
HyunChul
----------------------------------------------------------------------------
---------
public class LinkedListCount
{
Linkable head;
private final int MAXLINK = 1000;
private int linkCount = 0;
private int maxLinkCount = MAXLINK;
public interface Linkable
{
public Linkable getNext();
public void setNext(Linkable node);
}
public synchronized Linkable getHead()
{
return head;
}
public synchronized void setMaxLinkCount(int maxLinkCount)
{
this.maxLinkCount = maxLinkCount;
}
public synchronized boolean insertAtHead(Linkable node)
{
if (linkCount < maxLinkCount)
{
node.setNext(head);
head = node;
linkCount++;
return true;
} else
return false;
}
public synchronized boolean insertAtTail(Linkable node)
{
if (linkCount < maxLinkCount)
{
if(head == null)
head = node;
else
{
Linkable p, q;
for(p = head; (q=p.getNext())!= null;p = q);
p.setNext(node);
}
linkCount++;
return true;
} else
return false;
}
public synchronized Linkable removeFromHead()
{
Linkable node = head;
if(node != null)
{
head = node.getNext();
node.setNext(null);
linkCount--;
}
return node;
}
public synchronized Linkable removeFromTail()
{
if(head == null)
return null;
Linkable p = head, q=null, next = head.getNext();
if(next == null)
{
head = null;
linkCount--;
return p;
}
while((next = p.getNext()) != null)
{
q = p;
p = next;
}
q.setNext(null);
linkCount--;
return p;
}
public synchronized boolean remove(Linkable node)
{
if(head == null)
return false;
if(node.equals(head))
{
head = head.getNext();
linkCount--;
return true;
}
Linkable p = head, q = null;
while((q = p.getNext()) != null)
{
if(node.equals(q))
{
p.setNext(q.getNext());
linkCount--;
return true;
}
p = q;
}
return true;
}
public static class TestString
{
static class LinkableString implements Linkable
{
String str = new String();
Linkable next;
public LinkableString(String s)
{
this.str = s;
}
public Linkable getNext()
{
return next;
}
public void setNext(Linkable node)
{
next = node;
}
public String toString()
{
return str;
}
public boolean equals(Object o)
{
if(this == o)
return true;
if(!(o instanceof LinkableString))
return false;
if(((LinkableString)o).str.equals(this.str))
return true;
return false;
}
}
public static void main(String[] args)
{
LinkedListCount ll = new LinkedListCount();
ll.setMaxLinkCount(100);
if (ll.insertAtHead(new LinkableString("1")))
System.out.println("1 Insert Success");
else
System.out.println("1 Insert Fail");
if (ll.insertAtHead(new LinkableString("2")))
System.out.println("2 Insert Success");
else
System.out.println("2 Insert Fail");
if (ll.insertAtHead(new LinkableString("3")))
System.out.println("3 Insert Success");
else
System.out.println("3 Insert Fail");
if (ll.insertAtHead(new LinkableString("4")))
System.out.println("4 Insert Success");
else
System.out.println("4 Insert Fail");
if (ll.insertAtHead(new LinkableString("5")))
System.out.println("5 Insert Success");
else
System.out.println("5 Insert Fail");
if (ll.insertAtHead(new LinkableString("6")))
System.out.println("6 Insert Success");
else
System.out.println("6 Insert Fail");
System.out.println();
System.out.println(ll.removeFromHead());
System.out.println(ll.removeFromTail());
ll.remove(new LinkableString("3"));
System.out.println();
for(Linkable l = ll.getHead(); l != null; l = l.getNext())
System.out.println(l);
}
}
}
----- Original Message -----
From: "Shirley Chen" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, December 08, 2000 3:48 AM
Subject: LinkedList
> I am strugling so hard on this, could anybody help me? Here is my problem:
>
> I need a fixed size linkedlist (100 elements) to store string objects.
The
> reason for the fixed size is I don't know how many strings I will get, and
I
> don't want the linkedlist out grow so it will fill up the memory. When I
> got 101th string, I will delete the first one, and make the space for the
> new one. What is the efficient way to do that?
>
> Thanks
>
>
>
>
____________________________________________________________________________
_________
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