001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, 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 * [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 * ParamChecks.java
029 * ----------------
030 * (C) Copyright 2011, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 16-Oct-2011 : Version 1 (DG);
038 *
039 */
040
041package org.jfree.chart.util;
042
043/**
044 * A utility class for checking parameters.
045 *
046 * @since 1.0.14
047 */
048public class ParamChecks {
049
050    /**
051     * Throws an <code>IllegalArgumentException</code> if the supplied 
052     * <code>param</code> is <code>null</code>.
053     *
054     * @param param  the parameter to check (<code>null</code> permitted).
055     * @param name  the name of the parameter (to use in the exception message
056     *     if <code>param</code> is <code>null</code>).
057     *
058     * @throws IllegalArgumentException  if <code>param</code> is 
059     *     <code>null</code>.
060     *
061     * @since 1.0.14
062     */
063    public static void nullNotPermitted(Object param, String name) {
064        if (param == null) {
065            throw new IllegalArgumentException("Null '" + name + "' argument.");
066        }
067    }
068    
069    /**
070     * Throws an {@code IllegalArgumentException} if {@code value} is negative.
071     * 
072     * @param value  the value.
073     * @param name  the parameter name (for use in the exception message).
074     * 
075     * @since 1.0.18
076     */
077    public static void requireNonNegative(int value, String name) {
078        if (value < 0) {
079            throw new IllegalArgumentException("Require '" + name + "' (" 
080                    + value + ") to be non-negative.");
081        }
082    }
083}