com.netflix.astyanax.clock.MicrosecondsSyncClock Maven / Gradle / Ivy
/*******************************************************************************
* Copyright 2011 Netflix
*
* 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 com.netflix.astyanax.clock;
import com.netflix.astyanax.Clock;
/**
* Clock which uses a rolling counter to avoid duplicates.
*
* @author Patricio Echague ([email protected])
*/
public class MicrosecondsSyncClock implements Clock {
private static final long serialVersionUID = -4671061000963496156L;
private static long lastTime = -1;
private static final long ONE_THOUSAND = 1000L;
@Override
public long getCurrentTime() {
// The following simulates a microseconds resolution by advancing a
// static counter
// every time a client calls the createClock method, simulating a tick.
long us = System.currentTimeMillis() * ONE_THOUSAND;
// Synchronized to guarantee unique time within and across threads.
synchronized (MicrosecondsSyncClock.class) {
if (us > lastTime) {
lastTime = us;
}
else {
// the time i got from the system is equals or less
// (hope not - clock going backwards)
// One more "microsecond"
us = ++lastTime;
}
}
return us;
}
public String toString() {
return "MicrosecondsSyncClock";
}
}