package net.sf.dz;import java.util.Iterator;/** * The DIY Zoning model. * * Provides an entry point for the introspection required to create a {@link * net.sf.dz.view.View view}. * * @author Copyright &copy; <a href="mailto:vt@freehold.crocodile.org">Vadim Tkachenko</a> 2001-2002 * @version $Id: Model.java,v 1.4 2002/06/27 09:36:34 vtt Exp $ */public interface Model {    /**     * Get the iterator on the units in the model.     *     * Each element in the iterator is a {@link net.sf.dz.device.model.Unit     * logical HVAC unit}.     *     * @return Iterator on the unit set of the model.     *     * @exception IllegalStateException if the model is not in the     * appropriate state.     */    public Iterator iterator();}