Java Percentage Format formatAsPercent(double value, double maxValue, int fractionDigits)

Description

format As Percent

License

Apache License

Declaration

public static String formatAsPercent(double value, double maxValue,
            int fractionDigits) 

Method Source Code

//package com.java2s;
/*//w w  w  . j a  va  2  s .  c om
 * Copyright 2004-2010 Information & Software Engineering Group (188/1)
 *                     Institute of Software Technology and Interactive Systems
 *                     Vienna University of Technology, Austria
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.ifs.tuwien.ac.at/dm/somtoolbox/license.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

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

import java.util.HashMap;

public class Main {
    private static HashMap<String, DecimalFormat> decimalFormats = new HashMap<String, DecimalFormat>();

    public static String formatAsPercent(double value, double maxValue,
            int fractionDigits) {
        return format(value * 100d / maxValue, fractionDigits, false) + "%";
    }

    /**
     * Formats a double value with the given number of fractionDigits. uses {@link #format(double, int, boolean)} with
     * no trailing zeros.
     */
    public static String format(double number, int fractionDigits) {
        return format(number, fractionDigits, false);
    }

    /**
     * Formats a double value with the given number of fractionDigits.
     * 
     * @param withZeros indicates whether there should be trailing zeros to fill up all fraction digits
     */
    public static String format(double number, int fractionDigits,
            boolean withZeros) {
        return format(number, fractionDigits, withZeros, 1);
    }

    public static String format(double number, int fractionDigits,
            boolean withZeros, int leadingDigits) {
        return getDecimalFormat(fractionDigits, withZeros, leadingDigits)
                .format(number);
    }

    /** Formats a double value with the given number of digits, potentially including leading zeros. */
    public static String format(int number, int digits) {
        return getIntegerFormat(digits).format(number);
    }

    /** Returns a {@link DecimalFormat} with the given number of fractionDigits, with or without trailing zeros. */
    public static DecimalFormat getDecimalFormat(int fractionDigits,
            boolean withZeros, int leadingDigits) {
        String pattern = repeatString(leadingDigits, "0") + "."
                + repeatString(fractionDigits, withZeros ? "0" : "#");
        if (!decimalFormats.containsKey(pattern)) {
            // when initializing number formats, using US locale avoids format troubles on localized OS's (, instead of
            // .)
            DecimalFormat format = (DecimalFormat) NumberFormat
                    .getNumberInstance(java.util.Locale.US);
            format.applyPattern(pattern);
            decimalFormats.put(pattern, format);
        }
        return decimalFormats.get(pattern);
    }

    private static DecimalFormat getDecimalFormat(int digits) {
        String precision = "";
        for (int i = 0; i < digits; i++) {
            precision += "#";
        }
        final DecimalFormat decimalFormat = new DecimalFormat("#."
                + precision);
        return decimalFormat;
    }

    /**
     * Returns a {@link DecimalFormat} intended to formatting integers with the given number of digits, potentially with
     * leading zeros
     */
    public static DecimalFormat getIntegerFormat(int digits) {
        DecimalFormat format = (DecimalFormat) NumberFormat
                .getNumberInstance(java.util.Locale.US);
        format.applyPattern(repeatString(digits, "0"));
        return format;
    }

    public static String repeatString(int num, String s) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < num; i++) {
            sb.append(s);
        }
        return sb.toString();
    }
}

Related

1. calcPercent(double numerator, double denominator)
2. formatDecimal(double percent)
3. formatDoubleAsPercentString(Double d)
4. formatMicrosAsPercentage(long micros)
5. formatPercent(double done, int digits)