Java Decimal Round roundDecimalPlaces(final double input, final int decimalPlaces)

Description

round Decimal Places

License

Open Source License

Parameter

Parameter	Description
input	- The double you'd like to round the decimal places for
decimalPlaces	- The number of decimal places you'd like

Return

the formatted number

Declaration

public static String roundDecimalPlaces(final double input, final int decimalPlaces) 

Method Source Code

//package com.java2s;
/* Open Log Viewer/*from www  .  j  a v a  2  s.  c o m*/
 *
 * Copyright 2011
 *
 * This file is part of the OpenLogViewer project.
 *
 * OpenLogViewer software 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.
 *
 * OpenLogViewer software 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 any OpenLogViewer software.  If not, see http://www.gnu.org/licenses/
 *
 * I ask that if you make any changes to this file you fork the code on github.com!
 *
 */

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;

public class Main {
    private static final char DS = DecimalFormatSymbols.getInstance().getDecimalSeparator();
    private static final DecimalFormat CUSTOM = (DecimalFormat) NumberFormat.getNumberInstance();
    private static final DecimalFormat NORMAL = (DecimalFormat) NumberFormat.getNumberInstance();

    /**
     *
     * @param input - The double you'd like to round the decimal places for
     * @param decimalPlaces - The number of decimal places you'd like
     * @return the formatted number
     */
    public static String roundDecimalPlaces(final double input, final int decimalPlaces) {
        // Deal with zero or negative decimal places requested
        if (decimalPlaces <= 0) {
            return NORMAL.format(Math.round(input));
        }

        final StringBuilder format = new StringBuilder("###0" + DS);
        final StringBuilder negativeZero = new StringBuilder("-0" + DS);

        for (int i = 0; i < decimalPlaces; i++) {
            format.append('0');
            negativeZero.append('0');
        }

        CUSTOM.applyLocalizedPattern(format.toString());
        final StringBuilder output = new StringBuilder(CUSTOM.format(input));

        // Deal with negative zero
        if (output.toString().equals(negativeZero.toString())) {
            output.deleteCharAt(0);
        }

        return output.toString();
    }
}

Related

1. round(double unrounded, int precision)
2. round(final double value)
3. roundAlloc(Double alloc)
4. roundAndTruncate(double rawValue, int precision)
5. roundDecimal(double d, int radix)
6. roundDecimals(double d, int numOfDec)
7. roundDistanceFromMeterToKm(final double distanceInMeter)
8. roundDouble(double iVal)
9. roundDouble(double num, int decimal)