NioNetStackList.java

/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * http://www.gnu.org/copyleft/gpl.html
 */
package commons.mmocore;

/**
 * @author Forsaiken
 * @param <E>
 */
public final class NioNetStackList<E>
{
	private final NioNetStackNode _start = new NioNetStackNode();
	
	private final NioNetStackNodeBuf _buf = new NioNetStackNodeBuf();
	
	private NioNetStackNode _end = new NioNetStackNode();
	
	public NioNetStackList()
	{
		clear();
	}
	
	public final void addLast(final E elem)
	{
		final NioNetStackNode newEndNode = _buf.removeFirst();
		_end._value = elem;
		_end._next = newEndNode;
		_end = newEndNode;
	}
	
	public final E removeFirst()
	{
		final NioNetStackNode old = _start._next;
		final E value = old._value;
		_start._next = old._next;
		_buf.addLast(old);
		return value;
	}
	
	public final boolean isEmpty()
	{
		return _start._next == _end;
	}
	
	public final void clear()
	{
		_start._next = _end;
	}
	
	protected final class NioNetStackNode
	{
		protected NioNetStackNode _next;
		
		protected E _value;
	}
	
	private final class NioNetStackNodeBuf
	{
		private final NioNetStackNode _start = new NioNetStackNode();
		
		private NioNetStackNode _end = new NioNetStackNode();
		
		NioNetStackNodeBuf()
		{
			_start._next = _end;
		}
		
		final void addLast(final NioNetStackNode node)
		{
			node._next = null;
			node._value = null;
			_end._next = node;
			_end = node;
		}
		
		final NioNetStackNode removeFirst()
		{
			if (_start._next == _end)
			{
				return new NioNetStackNode();
			}
			
			final NioNetStackNode old = _start._next;
			_start._next = old._next;
			return old;
		}
	}
}