/*
* Copyright 1999-2015 dangdang.com.
* <p>
* 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.
* </p>
*/
package com.dangdang.ddframe.rdb.sharding.id.generator.self.time;
/**
* 时钟定义.
*
* @author gaohongtao
*/
public abstract class AbstractClock {
/**
* 创建系统时钟.
*
* @return 系统时钟
*/
public static AbstractClock systemClock() {
return new SystemClock();
}
/**
* 返回从纪元开始的毫秒数.
*
* @return 从纪元开始的毫秒数
*/
public abstract long millis();
private static final class SystemClock extends AbstractClock {
@Override
public long millis() {
return System.currentTimeMillis();
}
}
}