Negate a number - Java java.lang

Java examples for java.lang:Number

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Description

Negate a number

Demo Code

/*// ww  w  .  j  a  va2s .co m
 * This file is part of FFMQ.
 *
 * FFMQ 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 of the License, or
 * (at your option) any later version.
 *
 * FFMQ 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 FFMQ; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        Number n = new Integer(2);
        System.out.println(minus(n));
    }

    /**
     * Negate a number
     */
    public static Number minus(Number n) {
        Number value = normalize(n);
        Class<?> type = value.getClass();

        if (type == Long.class)
            return Long.valueOf(-n.longValue());

        return new Double(-n.doubleValue());
    }

    public static Number normalize(Number value) {
        Class<?> type = value.getClass();
        if (type == Long.class || type == Double.class)
            return value;

        if (isIntegerType(type))
            return Long.valueOf(value.longValue());
        else
            return new Double(value.doubleValue());
    }

    private static boolean isIntegerType(Class<?> type) {
        return type == Byte.class || type == Short.class
                || type == Integer.class || type == Long.class;
    }
}

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