com.github.xbn.examples.regexutil.non_xbn.UserInputNumInRangeWRegex.java Source code

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Here is the source code for com.github.xbn.examples.regexutil.non_xbn.UserInputNumInRangeWRegex.java

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/*license*\
   XBN-Java: Copyright (C) 2014, Jeff Epstein (aliteralmind __DASH__ github __AT__ yahoo __DOT__ com)
    
   This software is dual-licensed under the:
   - Lesser General Public License (LGPL) version 3.0 or, at your option, any later version;
   - Apache Software License (ASL) version 2.0.
    
   Either license may be applied at your discretion. More information may be found at
   - http://en.wikipedia.org/wiki/Multi-licensing.
    
   The text of both licenses is available in the root directory of this project, under the names "LICENSE_lgpl-3.0.txt" and "LICENSE_asl-2.0.txt". The latest copies may be downloaded at:
   - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
   - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
\*license*/
package com.github.xbn.examples.regexutil.non_xbn;

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang3.math.NumberUtils;

/**
  <p>Example code used in my <a href="http://aliteralmind.wordpress.com/2014/03/02/regex_numeric_range">blog post</a>: How to use regular expressions to validate number-ranges. This confirms a user-input number is a valid number by reading a string an testing it is numeric before converting it to an it--this loops until a valid number is provided.</p>
    
  <p>{@code java com.github.xbn.examples.regexutil.non_xbn.UserInputNumInRangeWRegex}</p>
    
* @since  0.1.0
* @author  Copyright (C) 2014, Jeff Epstein ({@code aliteralmind __DASH__ github __AT__ yahoo __DOT__ com}), dual-licensed under the LGPL (version 3.0 or later) or the ASL (version 2.0). See source code for details. <a href="http://xbnjava.aliteralmind.com">{@code http://xbnjava.aliteralmind.com}</a>, <a href="https://github.com/aliteralmind/xbnjava">{@code https://github.com/aliteralmind/xbnjava}</a>
 **/
public class UserInputNumInRangeWRegex {
    public static final void main(String[] ignored) {

        int num = -1;
        boolean isNum = false;

        int iRangeMax = 2055;

        //"": Dummy string, to reuse matcher
        Matcher mtchrNumNegThrPos = Pattern.compile("-?\\b(20(5[0-5]|[0-4][0-9])|1?[0-9]{1,3})\\b").matcher("");

        do {
            System.out.print("Enter a number between -" + iRangeMax + " and " + iRangeMax + ": ");
            String strInput = (new Scanner(System.in)).next();
            if (!NumberUtils.isNumber(strInput)) {
                System.out.println("Not a number. Try again.");
            } else if (!mtchrNumNegThrPos.reset(strInput).matches()) {
                System.out.println("Not in range. Try again.");
            } else {
                //Safe to convert
                num = Integer.parseInt(strInput);
                isNum = true;
            }
        } while (!isNum);

        System.out.println("Number: " + num);
    }
}