com.alibaba.rocketmq.common.SystemClock Maven / Gradle / Ivy
/**
* 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.
*/
package com.alibaba.rocketmq.common;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
/**
* @author vintage.wang
*/
public class SystemClock {
private final long precision;
private final AtomicLong now;
public SystemClock(long precision) {
this.precision = precision;
now = new AtomicLong(System.currentTimeMillis());
scheduleClockUpdating();
}
private void scheduleClockUpdating() {
ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {
@Override
public Thread newThread(Runnable runnable) {
Thread thread = new Thread(runnable, "System Clock");
thread.setDaemon(true);
return thread;
}
});
scheduler.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
now.set(System.currentTimeMillis());
}
}, precision, precision, TimeUnit.MILLISECONDS);
}
public long now() {
return now.get();
}
public long precision() {
return precision;
}
}