/*
* Copyright 2004-2015 the Seasar Foundation and the Others.
*
* Licensed 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.
*/
package org.seasar.framework.util;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.SecureRandom;
/**
* UUIDを作成するユーティリティです。
*
* @author higa
*
*/
public class UUID {
private static final byte[] DEFAULT_ADDRESS = new byte[] { (byte) 127,
(byte) 0, (byte) 0, (byte) 1 };
private static SecureRandom _random = new SecureRandom();
private static String _base = StringUtil.toHex(getAddress())
+ StringUtil.toHex(System.identityHashCode(_random));
/**
* インスタンスを構築します。
*/
protected UUID() {
}
/**
* UUIDを作成します。
*
* @return
*/
public static String create() {
StringBuffer buf = new StringBuffer(_base.length() * 2);
buf.append(_base);
int lowTime = (int) System.currentTimeMillis() >> 32;
StringUtil.appendHex(buf, lowTime);
StringUtil.appendHex(buf, _random.nextInt());
return buf.toString();
}
private static byte[] getAddress() {
try {
return InetAddress.getLocalHost().getAddress();
} catch (UnknownHostException ignore) {
return DEFAULT_ADDRESS;
}
}
}