Checks if the String contains only hexidecimal digits. - Java java.lang

Java examples for java.lang:String Hex

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Description

Checks if the String contains only hexidecimal digits.

Demo Code

/*/*from  ww  w .  jav  a2 s .  c o  m*/
 * Copyright 2013 Guidewire Software, Inc.
 */
/**
 * This class is based, in part, on org.apache.commons.lang.StringUtils and is intended
 * to break the dependency on that project.
 *
 * @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>
 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
 * @author Daniel L. Rall
 * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
 * @author <a href="mailto:ed@apache.org">Ed Korthof</a>
 * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
 * @author Stephen Colebourne
 * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
 * @author Holger Krauth
 * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @author Arun Mammen Thomas
 * @author Gary Gregory
 * @author Phil Steitz
 * @author Al Chou
 * @author Michael Davey
 * @author Reuben Sivan
 * @author Chris Hyzer
 *  Johnson

 */
//package com.java2s;

import java.util.regex.Pattern;

public class Main {
    public static void main(String[] argv) {
        String str = "java2s.com";
        System.out.println(isHexidecimal(str));
    }

    /**
     * <p>Checks if the String contains only hexidecimal digits.
     * A decimal point is not a hexidecimal digit and returns false.</p>
     *
     * <p><code>null</code> will return <code>false</code>.
     * An empty String ("") will return <code>true</code>.</p>
     *
     * <pre>
     * isHexidecimal(null)   = false
     * isHexidecimal("")     = true
     * isHexidecimal("  ")   = false
     * isHexidecimal("123")  = true
     * isHexidecimal("12 3") = false
     * isHexidecimal("ab2c") = true
     * isHexidecimal("ah2c") = false
     * isHexidecimal("12-3") = false
     * isHexidecimal("12.3") = false
     * </pre>
     *
     * @param str  the String to check, may be null
     * @return <code>true</code> if only contains hexidecimal digits, and is non-null
     */
    public static boolean isHexidecimal(String str) {
        if (str == null) {
            return false;
        }
        return Pattern.compile("[0-9a-fA-F]*").matcher(str).matches();
    }
}

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