Application: gvSIG desktop

/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2007 IVER T.I. and Generalitat Valenciana.

 *

 * 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

 * of the License, 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.

 */

package org.gvsig.raster.util;

/*

 * Created on 10-mar-2006

 *

 * gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * 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

 * of the License, 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.

 *

 * For more information, contact:

 */

import java.util.Vector;

/**

 * A simple FIFO queue class which causes the calling thread to wait if the

 * queue is empty and notifies threads that are waiting when it is not

 * empty.

 * 

 * @author Anil V (akv@eng.sun.com)

 */

public class Queue {

	private Vector vector = new Vector();

	/**

	 * Put the object into the queue.

	 * 

	 * @param object

	 *            the object to be appended to the queue.

	 */

	public synchronized void put(Object object) {

		vector.addElement(object);

		notify();

	}

	/**

	 * Pull the first object out of the queue. Wait if the queue is empty.

	 */

	public synchronized Object pull() {

		while (isEmpty())

			try {

				wait();

			} catch (InterruptedException ex) {

			}

			return get();

	}

	/**

	 * Get the first object out of the queue. Return null if the queue is

	 * empty.

	 */

	public synchronized Object get() {

		Object object = peek();

		if (object != null)

			vector.removeElementAt(0);

		return object;

	}

	/**

	 * Peek to see if something is available.

	 */

	public Object peek() {

		if (isEmpty())

			return null;

		return vector.elementAt(0);

	}

	/**

	 * Is the queue empty?

	 */

	public boolean isEmpty() {

		return vector.isEmpty();

	}

	/**

	 * How many elements are there in this queue?

	 */

	public int size() {

		return vector.size();

	}

}