Args.java

/* =====================================================================
 * OrsonPDF : a fast, light-weight PDF library for the Java(tm) platform
 * =====================================================================
 * 
 * (C)opyright 2013-2015, by Object Refinery Limited.  All rights reserved.
 *
 * Project Info:  http://www.object-refinery.com/orsonpdf/index.html
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 * 
 * If you do not wish to be bound by the terms of the GPL, an alternative
 * commercial license can be purchased.  For details, please see visit the
 * Orson PDF home page:
 * 
 * http://www.object-refinery.com/orsonpdf/index.html
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 */

package com.orsonpdf.util;

/**
 * A utility class that performs checks for method argument validity.
 */
public class Args {

    private Args() {
        // no need to instantiate this
    }
 
    /**
     * Checks that an argument is non-{@code null} and throws an 
     * {@code IllegalArgumentException} otherwise.
     * 
     * @param obj  the object to check for {@code null}.
     * @param ref  the text name for the parameter (to include in the exception
     *     message).
     */
    public static void nullNotPermitted(Object obj, String ref) {
        if (obj == null) {
            throw new IllegalArgumentException("Null '" + ref + "' argument.");
        }
    }
    
    /**
     * Checks an array to ensure it has the correct length and throws an
     * {@code IllegalArgumentException} if it does not.
     * 
     * @param length  the required length.
     * @param array  the array to check.
     * @param ref  the text name of the array parameter (to include in the 
     *     exception message).
     */
    public static void arrayMustHaveLength(int length, boolean[] array, 
            String ref) {
        nullNotPermitted(array, "array");
        if (array.length != length) {
            throw new IllegalArgumentException("Array '" + ref 
                    + "' requires length " + length);
        }
    }

    /**
     * Checks an array to ensure it has the correct length and throws an
     * {@code IllegalArgumentException} if it does not.
     * 
     * @param length  the required length.
     * @param array  the array to check.
     * @param ref  the text name of the array parameter (to include in the 
     *     exception message).
     */
    public static void arrayMustHaveLength(int length, double[] array, 
            String ref) {
        nullNotPermitted(array, "array");
        if (array.length != length) {
            throw new IllegalArgumentException("Array '" + ref 
                    + "' requires length " + length);
        }
    }
}