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‎org/kdc/MacAddress.java

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package org.kdc;
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// This is an incomplete class that I threw together fairly quickly because
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// I wanted to teach myself some more about Eclipse.
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import java.util.regex.Pattern;
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import java.util.regex.Matcher;
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// This class encapsulates a IEEE MAC Address.
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//
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// Currently this class will construct an object from a string having any one
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// of these formats:
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//
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// 00:11:22:33:44:55 (octets separated by colons)
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// aa:bb:cc:dd:ee:ff (lowercase hex digits)
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// AA:BB:CC:dd:ee:ff (uppercase hex digits)
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// 00-aa-22-CC-33:DD (digits separated by dashes)
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// 0:0a:1:2:34:56 (missing leading digits assumed to be "0)
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//
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// If a client of this class wishes to verify that the format of
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// a string is a valid MAC address, then they can invoke
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// MacAddress.isValidString(String).
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// Design note: I wrote this class in this way because in the past I have
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// worked with a system that dealt with a lot of bad MAC addresses
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// and there were lots of places in the code where either the code
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// either got into a bad state because of lack of input validation (this
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// both drove me nuts and cost a lot of time any money...)...or
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// else the code became really ugly because there were calls to
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// LegacyMacAddressClass.isValid() everywhere....even in code deeply
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// embedded in the system. It is my belief that if a MacAddress object
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// exists in a running system, that the object should be valid.
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public class MacAddress {
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// This array holds the raw bytes
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short[] address = new short[6]; // no unsigned ints in Java....
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// This array holds what the author has arbitrarily decided is a good String
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// representation of this object. The string will look like this:
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//
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// 00:0a:0b:0c:0d:0e
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String string;
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///////////////////////////////////////////////////////////////////////////
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static final Pattern pattern1;
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static {
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pattern1 = Pattern.compile("^\\s*" +
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"(\\p{XDigit}){1,2}[-:]" + // 1
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"(\\p{XDigit}){1,2}[-:]" + // 2
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"(\\p{XDigit}){1,2}[-:]" + // 3
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"(\\p{XDigit}){1,2}[-:]" + // 4
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"(\\p{XDigit}){1,2}[-:]" + // 5
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"(\\p{XDigit}){1,2}" + // 6
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"\\s*$");
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}
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///////////////////////////////////////////////////////////////////////////
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public static boolean isValidString(String s)
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{
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Matcher matcher = pattern1.matcher(s);
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return matcher.matches();
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}
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///////////////////////////////////////////////////////////////////////////
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private class MacMatchResult {
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boolean valid = false;
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short[] address = null;
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}
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///////////////////////////////////////////////////////////////////////////
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private static boolean isValidString(String s, MacMatchResult mmr) {
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Matcher matcher = pattern1.matcher(s);
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if (! matcher.matches()) {
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mmr.valid= false;
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}
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else {
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mmr.valid = true;
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mmr.address = new short[6];
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mmr.address[0] = Short.parseShort(matcher.group(1), 16);
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mmr.address[1] = Short.parseShort(matcher.group(2), 16);
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mmr.address[2] = Short.parseShort(matcher.group(3), 16);
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mmr.address[3] = Short.parseShort(matcher.group(4), 16);
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mmr.address[4] = Short.parseShort(matcher.group(5), 16);
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mmr.address[5] = Short.parseShort(matcher.group(6), 16);
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}
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return mmr.valid;
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}
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///////////////////////////////////////////////////////////////////////////
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/**
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* @param s The human-readable MAC Address string to create this object from.
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*/
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public MacAddress(String s)
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{
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MacMatchResult mmr = new MacMatchResult();
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if (! isValidString(s, mmr)) {
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throw new IllegalArgumentException("Malformed MAC Address: " + s);
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}
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System.arraycopy(mmr.address, 0, this.address, 0, 6);
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this.string = String.format("%02x:%02x:%02x:%02x:%02x:%02x",
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this.address[0],
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this.address[1],
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this.address[2],
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this.address[3],
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this.address[4],
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this.address[5]);
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}
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///////////////////////////////////////////////////////////////////////////
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public String toString()
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{
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return this.string;
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}
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///////////////////////////////////////////////////////////////////////////
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@Override public boolean equals(Object o)
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{
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if (! (o instanceof MacAddress)) {
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return false;
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}
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MacAddress that = (MacAddress)o;
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return this.address[0] == that.address[0] &&
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this.address[1] == that.address[1] &&
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this.address[2] == that.address[2] &&
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this.address[3] == that.address[3] &&
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this.address[4] == that.address[4] &&
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this.address[5] == that.address[5];
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}
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///////////////////////////////////////////////////////////////////////////
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public int hashCode()
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{
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return string.hashCode();
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}
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}

‎org/kdc/MacAddressTest.java

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package org.kdc;
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import org.junit.*;
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import static org.junit.Assert.*;
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import org.junit.Test;
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import org.kdc.MacAddress;
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public class MacAddressTest {
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@Before
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public void setUp()
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{
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}
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@Test(expected=NullPointerException.class)
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public void offerNull()
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{
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new MacAddress(null);
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}
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@Test
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public void simpleTest() {
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new MacAddress("00:11:22:33:44:55");
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new MacAddress("00-11-22-33-44-55");
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new MacAddress("0-1-2-3-4-5");
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}
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@Test(expected=IllegalArgumentException.class)
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public void malformedTest1() {
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new MacAddress("foo");
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}
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@Test(expected=IllegalArgumentException.class)
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public void malformedTest2() {
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new MacAddress("00:11:22:33:44:ag");
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}
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@Test
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public void simpleEqualsTest1() {
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MacAddress a = new MacAddress("aa:bb:cc:dd:ee:ff");
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MacAddress b = new MacAddress("AA:BB:CC:DD:EE:FF");
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assertTrue(a.equals(b));
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}
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@Test
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public void simpleEqualsTest2() {
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MacAddress a = new MacAddress("01:02:03:0a:0b:0c");
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MacAddress b = new MacAddress("1:2:3:a:b:c");
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assertTrue(a.equals(b));
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}
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@Test
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public void simpleHashcodeTest() {
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MacAddress a = new MacAddress("aa:bb:cc:dd:ee:ff");
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MacAddress b = new MacAddress("AA:BB:CC:DD:EE:FF");
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assertTrue(a.hashCode() == b.hashCode());
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}
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}

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