/**
 * Created on 24.03.2005
 *
 * @author Jens Guenther
 */
package de.unirostock.Singleton.example;

public class ShipMarket
{
	/**
	 *  
	 * @uml.property name="itsNumShipInStock" multiplicity="(0 1)"
	 */
	private int itsNumShipsInStock = 0;

	/**
	 *  
	 * @uml.property name="instance" multiplicity="(0 1)"
	 */
	private static ShipMarket itsInstance;

	/**
	 *  
	 * @uml.property name="instance"
	 */
	public static synchronized ShipMarket getInstance() {
		if( itsInstance == null )
			itsInstance = new ShipMarket();
		return itsInstance;
	}

	private ShipMarket() {
	}

	public boolean sellShip() {
		if( itsNumShipsInStock != 0 ){
			itsNumShipsInStock--;
			return true;
		}
		return false;
	}

	public void buyShip() {
		itsNumShipsInStock++;
	}

	public int getNumShipsToSell() {
		return itsNumShipsInStock;
	}

}