com.alibaba.metrics.Clock 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.metrics;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
/**
* An abstraction for how time passes. It is passed to {@link Timer} to track timing.
*/
public abstract class Clock {
/**
* Returns the current time tick.
*
* @return time tick in nanoseconds
*/
public abstract long getTick();
/**
* Returns the current time in milliseconds.
*
* @return time in milliseconds
*/
public long getTime() {
return System.currentTimeMillis();
}
private static final Clock DEFAULT = new UserTimeClock();
/**
* The default clock to use.
*
* @return the default {@link Clock} instance
*
* @see Clock.UserTimeClock
*/
public static Clock defaultClock() {
return DEFAULT;
}
/**
* A clock implementation which returns the current time in epoch nanoseconds.
*/
public static class UserTimeClock extends Clock {
@Override
public long getTick() {
return System.nanoTime();
}
}
/**
* A clock implementation which returns the current thread's CPU time.
*/
public static class CpuTimeClock extends Clock {
private static final ThreadMXBean THREAD_MX_BEAN = ManagementFactory.getThreadMXBean();
@Override
public long getTick() {
return THREAD_MX_BEAN.getCurrentThreadCpuTime();
}
}
}