001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006     *
007     * Project Info:  http://www.jfree.org/jfreechart/index.html
008     *
009     * This library is free software; you can redistribute it and/or modify it 
010     * under the terms of the GNU Lesser General Public License as published by 
011     * the Free Software Foundation; either version 2.1 of the License, or 
012     * (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but 
015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017     * License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this library; if not, write to the Free Software
021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022     * USA.  
023     *
024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025     * in the United States and other countries.]
026     *
027     * ---------------------
028     * EntityCollection.java
029     * ---------------------
030     * (C) Copyright 2002-2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: EntityCollection.java,v 1.5.2.1 2005/10/25 20:41:59 mungady Exp $
036     *
037     * Changes
038     * -------
039     * 23-May-2002 : Version 1 (DG);
040     * 25-Jun-2002 : Removed unnecessary import (DG);
041     * 26-Jun-2002 : Added iterator() method (DG);
042     * 03-Oct-2002 : Fixed errors reported by Checkstyle (DG);
043     * 30-Jan-2004 : Added a method to add a collection of entities.
044     * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0 
045     *               release (DG);
046     * 18-Jan-2005 : Added getEntity() and getEntityCount() methods (DG);
047     *
048     */
049    
050    package org.jfree.chart.entity;
051    
052    import java.util.Collection;
053    import java.util.Iterator;
054    
055    /**
056     * This interface defines the methods used to access an ordered list of
057     * {@link ChartEntity} objects.
058     */
059    public interface EntityCollection {
060    
061        /**
062         * Clears all entities.
063         */
064        public void clear();
065    
066        /**
067         * Adds an entity to the collection.
068         *
069         * @param entity  the entity (<code>null</code> not permitted).
070         */
071        public void add(ChartEntity entity);
072    
073        /**
074         * Adds the entities from another collection to this collection.
075         * 
076         * @param collection  the other collection.
077         */
078        public void addAll(EntityCollection collection);
079        
080        /**
081         * Returns an entity whose area contains the specified point.
082         *
083         * @param x  the x coordinate.
084         * @param y  the y coordinate.
085         *
086         * @return The entity.
087         */
088        public ChartEntity getEntity(double x, double y);
089    
090        /**
091         * Returns an entity from the collection.
092         * 
093         * @param index  the index (zero-based).
094         * 
095         * @return An entity.
096         */
097        public ChartEntity getEntity(int index);
098        
099        /**
100         * Returns the entity count.
101         * 
102         * @return The entity count.
103         */
104        public int getEntityCount();
105        
106        /**
107         * Returns the entities in an unmodifiable collection.
108         * 
109         * @return The entities.
110         */
111        public Collection getEntities();
112        
113        /**
114         * Returns an iterator for the entities in the collection.
115         *
116         * @return An iterator.
117         */
118        public Iterator iterator();
119    
120    }