/* ===========================================================

 * JFreeChart : a free chart library for the Java(tm) platform

 * ===========================================================

 *

 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.

 *

 * Project Info:  http://www.jfree.org/jfreechart/index.html

 *

 * This library is free software; you can redistribute it and/or modify it under the terms

 * of the GNU Lesser General Public License as published by the Free Software Foundation;

 * either version 2.1 of the License, or (at your option) any later version.

 *

 * This library 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License along with this

 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 *

 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 

 * in the United States and other countries.]

 *

 * ---------------------

 * EntityCollection.java

 * ---------------------

 * (C) Copyright 2002-2004, by Object Refinery Limited.

 *

 * Original Author:  David Gilbert (for Object Refinery Limited);

 * Contributor(s):   -;

 *

 * $Id: EntityCollection.java,v 1.1 2004/08/31 14:32:37 mungady Exp $

 *

 * Changes

 * -------

 * 23-May-2002 : Version 1 (DG);

 * 25-Jun-2002 : Removed unnecessary import (DG);

 * 26-Jun-2002 : Added iterator() method (DG);

 * 03-Oct-2002 : Fixed errors reported by Checkstyle (DG);

 * 30-Jan-2004 : Added a method to add a collection of entities.

 *

 */



package org.jfree.chart.entity;



import java.util.Collection;

import java.util.Iterator;



/**

 * Defines the methods that a collection of entities is required to implement.

 */

public interface EntityCollection {



    /**

     * Clears all entities.

     */

    public void clear();



    /**

     * Adds an entity to the collection.

     *

     * @param entity  the entity.

     */

    public void addEntity(ChartEntity entity);



    /**

     * Adds the entities from another collection to this collection.

     * 

     * @param collection  the other collection.

     */

    public void addEntities(EntityCollection collection);

    

    /**

     * Returns an entity whose area contains the specified point.

     *

     * @param x  the x coordinate.

     * @param y  the y coordinate.

     *

     * @return The entity.

     */

    public ChartEntity getEntity(double x, double y);



    /**

     * Returns the entities in an unmodifiable collection.

     * 

     * @return The entities.

     */

    public Collection getEntities();

    

    /**

     * Returns an iterator for the entities in the collection.

     *

     * @return An iterator.

     */

    public Iterator iterator();



}

