standardentitycollection.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 194 行

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, 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.]
 *
 * -----------------------------
 * StandardEntityCollection.java
 * -----------------------------
 * (C) Copyright 2001-2005, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: StandardEntityCollection.java,v 1.8 2005/05/20 08:30:07 mungady Exp $
 *
 * Changes
 * -------
 * 23-May-2002 : Version 1 (DG);
 * 26-Jun-2002 : Added iterator() method (DG);
 * 03-Oct-2002 : Fixed errors reported by Checkstyle (DG);
 * 19-May-2004 : Implemented Serializable (DG);
 * 29-Sep-2004 : Renamed addEntity() --> add() and addEntities() 
 *               --> addAll() (DG);
 * 19-Jan-2005 : Changed storage from Collection --> List (DG);
 * 20-May-2005 : Fixed bug 1113521 - inefficiency in getEntity() method (DG);
 *
 */

package org.jfree.chart.entity;

import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.jfree.util.ObjectUtilities;

/**
 * A standard implementation of the {@link EntityCollection} interface.
 */
public class StandardEntityCollection implements EntityCollection, 
                                                 Cloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 5384773031184897047L;
    
    /** Storage for the entities. */
    private List entities;

    /**
     * Constructs a new entity collection (initially empty).
     */
    public StandardEntityCollection() {
        this.entities = new java.util.ArrayList();
    }

    /**
     * Returns the number of entities in the collection.
     * 
     * @return The entity count.
     */
    public int getEntityCount() {
        return this.entities.size();
    }
    
    /**
     * Returns a chart entity from the collection.
     * 
     * @param index  the entity index.
     * 
     * @return The entity.
     */
    public ChartEntity getEntity(int index) {
        return (ChartEntity) this.entities.get(index);
    }
    
    /**
     * Clears the entities.
     */
    public void clear() {
        this.entities.clear();
    }

    /**
     * Adds an entity to the collection.
     *
     * @param entity  the entity (<code>null</code> not permitted).
     */
    public void add(ChartEntity entity) {
        if (entity == null) {
            throw new IllegalArgumentException("Null 'entity' argument.");
        }
        this.entities.add(entity);
    }
    
    /**
     * Adds all the entities from the specified collection.
     * 
     * @param collection  the collection of entities.
     */
    public void addAll(EntityCollection collection) {
        this.entities.addAll(collection.getEntities());
    }

    /**
     * Returns the last entity in the list with an area that encloses the 
     * specified coordinates, or <code>null</code> if there is no such entity.
     *
     * @param x  the x coordinate.
     * @param y  the y coordinate.
     *
     * @return The entity (possibly <code>null</code>).
     */
    public ChartEntity getEntity(double x, double y) {
        int entityCount = this.entities.size();
        for (int i = entityCount - 1; i >= 0; i--) {
            ChartEntity entity = (ChartEntity) this.entities.get(i);
            if (entity.getArea().contains(x, y)) {
                return entity;
            }
        }
        return null;
    }

    /**
     * Returns the entities in an unmodifiable collection.
     * 
     * @return The entities.
     */
    public Collection getEntities() {
        return Collections.unmodifiableCollection(this.entities);
    }
    
    /**
     * Returns an iterator for the entities in the collection.
     *
     * @return An iterator.
     */
    public Iterator iterator() {
        return this.entities.iterator();
    }
    
    /**
     * Tests this object for equality with an arbitrary object.
     * 
     * @param obj  the object to test against (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;   
        }
        if (obj instanceof StandardEntityCollection) {
            StandardEntityCollection that = (StandardEntityCollection) obj;
            return ObjectUtilities.equal(this.entities, that.entities);
        }
        return false;
    }

    /**
     * Returns a clone.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException if the object cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {
        return super.clone();   
    }

}