jfreechart example source code file (ArrowNeedle.java)

This example jfreechart source code file (ArrowNeedle.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

arrowneedle, arrowneedle, awt, cloneable, clonenotsupportedexception, clonenotsupportedexception, generalpath, generalpath, geometry, io, meterneedle, object, object, point2d, rectangle2d, serializable, shape

The jfreechart ArrowNeedle.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ----------------
 * ArrowNeedle.java
 * ----------------
 * (C) Copyright 2002-2008, by the Australian Antarctic Division and
 *                          Contributors.
 *
 * Original Author:  Bryan Scott (for the Australian Antarctic Division);
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * Changes:
 * --------
 * 25-Sep-2002 : Version 1, contributed by Bryan Scott (DG);
 * 27-Mar-2003 : Implemented Serializable (DG);
 * 09-Sep-2003 : Added equals() method (DG);
 * 08-Jun-2005 : Implemented Cloneable (DG);
 * 22-Nov-2007 : Added hashCode() implementation (DG);
 *
 */

package org.jfree.chart.needle;

import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;

import org.jfree.chart.HashUtilities;

/**
 * A needle in the shape of an arrow.
 */
public class ArrowNeedle extends MeterNeedle
                         implements Cloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -5334056511213782357L;

    /**
     * A flag controlling whether or not there is an arrow at the top of the
     * needle.
     */
    private boolean isArrowAtTop = true;

    /**
     * Constructs a new arrow needle.
     *
     * @param isArrowAtTop  a flag that controls whether or not there is an
     *                      arrow at the top of the needle.
     */
    public ArrowNeedle(boolean isArrowAtTop) {
        this.isArrowAtTop = isArrowAtTop;
    }

    /**
     * Draws the needle.
     *
     * @param g2  the graphics device.
     * @param plotArea  the plot area.
     * @param rotate  the rotation point.
     * @param angle  the angle.
     */
    protected void drawNeedle(Graphics2D g2, Rectangle2D plotArea,
                              Point2D rotate, double angle) {

        Line2D shape = new Line2D.Float();
        Shape d = null;

        float x = (float) (plotArea.getMinX() +  (plotArea.getWidth() / 2));
        float minY = (float) plotArea.getMinY();
        float maxY = (float) plotArea.getMaxY();
        shape.setLine(x, minY, x, maxY);

        GeneralPath shape1 = new GeneralPath();
        if (this.isArrowAtTop) {
            shape1.moveTo(x, minY);
            minY += 4 * getSize();
        }
        else {
            shape1.moveTo(x, maxY);
            minY = maxY - 4 * getSize();
        }
        shape1.lineTo(x + getSize(), minY);
        shape1.lineTo(x - getSize(), minY);
        shape1.closePath();

        if ((rotate != null) && (angle != 0)) {
            getTransform().setToRotation(angle, rotate.getX(), rotate.getY());
            d = getTransform().createTransformedShape(shape);
        }
        else {
            d = shape;
        }
        defaultDisplay(g2, d);

        if ((rotate != null) && (angle != 0)) {
            d = getTransform().createTransformedShape(shape1);
        }
        else {
            d = shape1;
        }
        defaultDisplay(g2, d);

    }

    /**
     * Tests another object for equality with this object.
     *
     * @param obj  the object to test (<code>null permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof ArrowNeedle)) {
            return false;
        }
        if (!super.equals(obj)) {
            return false;
        }
        ArrowNeedle that = (ArrowNeedle) obj;
        if (this.isArrowAtTop != that.isArrowAtTop) {
            return false;
        }
        return true;
    }

    /**
     * Returns a hash code for this instance.
     *
     * @return A hash code.
     */
    public int hashCode() {
        int result = super.hashCode();
        result = HashUtilities.hashCode(result, this.isArrowAtTop);
        return result;
    }

    /**
     * Returns a clone of this needle.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException if the <code>ArrowNeedle
     *     cannot be cloned (in theory, this should not happen).
     */
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

}