Java Parse Double ParseDoubleEx(String s, double value_if_fault)

Description

Parse a string containing a double.

License

Open Source License

Parameter

Parameter	Description
s	Input string containing the double

Exception

Parameter	Description
ParseException	an exception

Return

Parsed value in double format

Declaration

public static double ParseDoubleEx(String s, double value_if_fault) 

Method Source Code

//package com.java2s;
/*/*  w w  w .  ja v a  2 s. co m*/
 * Course Generator
 * Copyright (C) 2016 Pierre Delore
 *
 * 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/>.
 */

import java.text.DecimalFormat;
import java.text.ParseException;

public class Main {
    /**
     * Parse a string containing a double. The separator can be "." or ","
     * 
     * @param s
     *            Input string containing the double
     * @return Parsed value in double format
     * @throws ParseException
     */
    public static double ParseDoubleEx(String s, double value_if_fault) { // throws
        // ParseException{
        int pos, step;
        double v;
        String str, s1;
        boolean ok, error;

        char decimalseparator = new DecimalFormat().getDecimalFormatSymbols().getDecimalSeparator();

        v = 0.0;
        str = "";

        // -- Input string empty
        s1 = s.trim();
        if (s1.isEmpty()) {
            return value_if_fault; // Return the fault value
        }

        // -- Let go
        ok = true;
        error = false;
        step = 0;
        pos = 0;
        while ((pos < s1.length()) && (ok) && (!error)) {
            switch (step) {
            case 0: { // '+' ou '-'
                if (s1.charAt(pos) == '+') {
                    str = str + s1.charAt(pos);
                    pos++;
                } else if (s1.charAt(pos) == '-') {
                    str = str + s1.charAt(pos);
                    pos++;
                }
                step = 1;
                break;
            } // Case 0

            case 1: { // Digit?
                if (Character.isDigit(s1.charAt(pos))) {
                    str = str + s1.charAt(pos);
                    pos++;
                } else { // Separator?
                    if ((s1.charAt(pos) == ',') || (s1.charAt(pos) == '.')) {
                        str = str + decimalseparator;
                        pos++;
                        step = 2;
                    } else {
                        error = true;
                        // step = 10;
                    }
                }
                break;
            } // Case 1

            case 2: { // Digit?
                if (Character.isDigit(s1.charAt(pos))) {
                    str = str + s1.charAt(pos);
                    pos++;
                } else {
                    error = true;
                }
                break;
            } // Case 2
              // case 10: { //Error
              // error=true;
              // ok=false;
              // break;
              // }

            } // Case
        } // While

        if (error)
            v = value_if_fault;
        else {
            // -- Convert the string to double
            try {
                DecimalFormat decimalFormat = new DecimalFormat("#");
                v = decimalFormat.parse(str).doubleValue();
            } catch (ParseException e) {
                // A problem! set the "fault" value
                v = value_if_fault;
            }
        }

        return v;
    }
}

Related

1. parseDouble(String s, Locale locale)
2. parseDouble(String str)
3. parseDouble(String str)
4. parseDouble(String stringValue)
5. parseDouble(String value)
6. parseDoubleInCurrentDefaultLocale(String text)
7. parseInternationalDouble(String number)
8. parseToCientificNotation(double value)
9. parseToEngineeringNotation(double val, int decimalHouses)