001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-present, by David Gilbert 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * ---------------------
028 * EntityCollection.java
029 * ---------------------
030 * (C) Copyright 2002-present, by David Gilbert.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.chart.entity;
038
039import java.util.Collection;
040import java.util.Iterator;
041
042/**
043 * This interface defines the methods used to access an ordered list of
044 * {@link ChartEntity} objects.
045 */
046public interface EntityCollection {
047
048    /**
049     * Clears all entities.
050     */
051    void clear();
052
053    /**
054     * Adds an entity to the collection.
055     *
056     * @param entity  the entity ({@code null} not permitted).
057     */
058    void add(ChartEntity entity);
059
060    /**
061     * Adds the entities from another collection to this collection.
062     *
063     * @param collection  the other collection.
064     */
065    void addAll(EntityCollection collection);
066
067    /**
068     * Returns an entity whose area contains the specified point.
069     *
070     * @param x  the x coordinate.
071     * @param y  the y coordinate.
072     *
073     * @return The entity.
074     */
075    ChartEntity getEntity(double x, double y);
076
077    /**
078     * Returns an entity from the collection.
079     *
080     * @param index  the index (zero-based).
081     *
082     * @return An entity.
083     */
084    ChartEntity getEntity(int index);
085
086    /**
087     * Returns the entity count.
088     *
089     * @return The entity count.
090     */
091    int getEntityCount();
092
093    /**
094     * Returns the entities in an unmodifiable collection.
095     *
096     * @return The entities.
097     */
098    Collection getEntities();
099
100    /**
101     * Returns an iterator for the entities in the collection.
102     *
103     * @return An iterator.
104     */
105    Iterator iterator();
106
107}