Java Fraction Format format(double val)

Description

format

License

Apache License

Declaration

public static String format(double val) 

Method Source Code

//package com.java2s;
/********************************************************************
*
*    Copyright 2011 Brendan O'Fallon// www  .j  a v a 2  s.c  o  m
*
*   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.apache.org/licenses/LICENSE-2.0
*
*   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;

public class Main {
    static NumberFormat formatter = new DecimalFormat("0.0###");

    public static String format(double val) {
        if (Double.isNaN(val)) {
            return "?";
        }

        double absVal = Math.abs(val);

        if (absVal > 1)
            formatter.setMaximumFractionDigits(1);
        else {
            double log = Math.log10(absVal);
            int dig = -1 * (int) Math.round(log) + 1;
            formatter.setMaximumFractionDigits(dig);
        }

        return formatter.format(val);
    }

    public static String format(double val, int digits) {
        double absVal = Math.abs(val);

        if (absVal > 1)
            formatter.setMaximumFractionDigits(digits);
        else {
            double log = Math.log10(absVal);
            int dig = -1 * (int) Math.round(log) + digits;
            formatter.setMaximumFractionDigits(dig);
        }

        return formatter.format(val);
    }
}

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