Mega Code Archive
Thread-safe version of the Axiom UUIDGenerator
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;
/**
* This is a thread-safe version of the Axiom UUIDGenerator
* to be used until it is fixed in the next Axiom release
*/
public class UUIDGenerator {
/** This class will give UUIDs for axis2. */
private static String baseUUID = null;
private static long incrementingValue = 0;
private static Random myRand = null;
private static boolean useNano = false;
/**
* MD5 a random string with localhost/date etc will return 128 bits construct a string of 18
* characters from those bits.
*
* @return string
*/
public static String getUUID() {
if (baseUUID == null) {
baseUUID = getInitialUUID();
baseUUID = "urn:uuid:" + baseUUID;
}
if (++incrementingValue >= Long.MAX_VALUE) {
incrementingValue = 0;
}
if (useNano) {
return baseUUID + (System.nanoTime() + incrementingValue) +
Integer.toString(myRand.nextInt());
} else {
return baseUUID + (System.currentTimeMillis() + incrementingValue +
Integer.toString(myRand.nextInt()));
}
}
protected static String getInitialUUID() {
try {
if (System.class.getMethod("nanoTime", new Class[0]) != null) {
useNano = true;
}
} catch (NoSuchMethodException ignore) {}
if (myRand == null) {
myRand = new Random();
}
long rand = myRand.nextLong();
String sid;
try {
sid = InetAddress.getLocalHost().toString();
} catch (UnknownHostException e) {
sid = Thread.currentThread().getName();
}
StringBuffer sb = new StringBuffer();
sb.append(sid);
sb.append(":");
sb.append(Long.toString(rand));
MessageDigest md5 = null;
try {
md5 = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
//System.out.println("Error: " + e);
//todo heve to be properly handle
}
md5.update(sb.toString().getBytes());
byte[] array = md5.digest();
StringBuffer sb2 = new StringBuffer();
for (int j = 0; j < array.length; ++j) {
int b = array[j] & 0xFF;
sb2.append(Integer.toHexString(b));
}
int begin = myRand.nextInt();
if (begin < 0) begin = begin * -1;
begin = begin % 8;
return sb2.toString().substring(begin, begin + 18).toUpperCase();
}
}
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