EnglishNumberToWords.java

package com.jenxsol.custom.listview.frags;

import java.text.DecimalFormat;

public class EnglishNumberToWords
{

    private static final String[] tensNames = { "", " ten", " twenty", " thirty", " forty",
            " fifty", " sixty", " seventy", " eighty", " ninety" };

    private static final String[] numNames = { "", " one", " two", " three", " four", " five",
            " six", " seven", " eight", " nine", " ten", " eleven", " twelve", " thirteen",
            " fourteen", " fifteen", " sixteen", " seventeen", " eighteen", " nineteen" };

    private static String convertLessThanOneThousand(int number)
    {
        String soFar;

        if (number % 100 < 20)
        {
            soFar = numNames[number % 100];
            number /= 100;
        } else
        {
            soFar = numNames[number % 10];
            number /= 10;

            soFar = tensNames[number % 10] + soFar;
            number /= 10;
        }
        if (number == 0)
            return soFar;
        return numNames[number] + " hundred" + soFar;
    }

    public static String convert(long number)
    {
        // 0 to 999 999 999 999
        if (number == 0)
        {
            return "zero";
        }

        String snumber = Long.toString(number);

        // pad with "0"
        String mask = "000000000000";
        DecimalFormat df = new DecimalFormat(mask);
        snumber = df.format(number);

        // XXXnnnnnnnnn
        int billions = Integer.parseInt(snumber.substring(0, 3));
        // nnnXXXnnnnnn
        int millions = Integer.parseInt(snumber.substring(3, 6));
        // nnnnnnXXXnnn
        int hundredThousands = Integer.parseInt(snumber.substring(6, 9));
        // nnnnnnnnnXXX
        int thousands = Integer.parseInt(snumber.substring(9, 12));

        String tradBillions;
        switch (billions)
        {
            case 0:
                tradBillions = "";
                break;
            case 1:
                tradBillions = convertLessThanOneThousand(billions) + " billion ";
                break;
            default:
                tradBillions = convertLessThanOneThousand(billions) + " billion ";
        }
        String result = tradBillions;

        String tradMillions;
        switch (millions)
        {
            case 0:
                tradMillions = "";
                break;
            case 1:
                tradMillions = convertLessThanOneThousand(millions) + " million ";
                break;
            default:
                tradMillions = convertLessThanOneThousand(millions) + " million ";
        }
        result = result + tradMillions;

        String tradHundredThousands;
        switch (hundredThousands)
        {
            case 0:
                tradHundredThousands = "";
                break;
            case 1:
                tradHundredThousands = "one thousand ";
                break;
            default:
                tradHundredThousands = convertLessThanOneThousand(hundredThousands) + " thousand ";
        }
        result = result + tradHundredThousands;

        String tradThousand;
        tradThousand = convertLessThanOneThousand(thousands);
        result = result + tradThousand;

        // remove extra spaces!
        return result.replaceAll("^\\s+", "").replaceAll("\\b\\s{2,}\\b", " ");
    }

}