/*

* Copyright 1990-2008, Mark Little, University of Newcastle upon Tyne

* and others contributors as indicated

* by the @authors tag. All rights reserved.

* See the copyright.txt in the distribution for a

* full listing of individual contributors.

* This copyrighted material is made available to anyone wishing to use,

* modify, copy, or redistribute it subject to the terms and conditions

* of the GNU Lesser General Public License, v. 2.1.

* This program is distributed in the hope that it will be useful, but WITHOUT A

* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A

* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

* You should have received a copy of the GNU Lesser General Public License,

* v.2.1 along with this distribution; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

* MA 02110-1301, USA.

*

* (C) 1990-2008,

*/

package org.javasim.examples.basic;

import java.util.NoSuchElementException;

public class Queue

{

public Queue()

{

head = null;

length = 0;

}

public boolean isEmpty ()

{

if (length == 0)

return true;

else

return false;

}

public long queueSize ()

{

return length;

}

public Job dequeue () throws NoSuchElementException

{

if (isEmpty())

throw new NoSuchElementException();

List ptr = head;

head = head.next;

length--;

return ptr.work;

}

public void enqueue (Job toadd)

{

if (toadd == null)

return;

List ptr = head;

if (isEmpty())

{

head = new List();

ptr = head;

}

else

{

while (ptr.next != null)

ptr = ptr.next;

ptr.next = new List();

ptr = ptr.next;

}

ptr.next = null;

ptr.work = toadd;

length++;

}

private List head;

private long length;

}

/* This is the queue on which Jobs are placed before they are used. */

class List

{

public List()

{

work = null;

next = null;

}

public Job work;

public List next;

}