001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2007, 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 * LineFunction2D.java
029 * -------------------
030 * (C) Copyright 2002-2007, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes:
036 * --------
037 * 01-Oct-2002 : Version 1 (DG);
038 *
039 */
040
041 package org.jfree.data.function;
042
043
044 /**
045 * A function in the form y = a + bx.
046 */
047 public class LineFunction2D implements Function2D {
048
049 /** The intercept. */
050 private double a;
051
052 /** The slope of the line. */
053 private double b;
054
055 /**
056 * Constructs a new line function.
057 *
058 * @param a the intercept.
059 * @param b the slope.
060 */
061 public LineFunction2D(double a, double b) {
062 this.a = a;
063 this.b = b;
064 }
065
066 /**
067 * Returns the function value.
068 *
069 * @param x the x-value.
070 *
071 * @return The value.
072 */
073 public double getValue(double x) {
074 return this.a + this.b * x;
075 }
076
077 }