/*
* 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 org.apache.flink.runtime.util.clock;
/**
* A clock that returns the time of the system / process.
*
* <p>This clock uses {@link System#currentTimeMillis()} for <i>absolute time</i>
* and {@link System#nanoTime()} for <i>relative time</i>.
*
* <p>This SystemClock exists as a singleton instance.
*/
public class SystemClock extends Clock {
private static final SystemClock INSTANCE = new SystemClock();
public static SystemClock getInstance() {
return INSTANCE;
}
// ------------------------------------------------------------------------
@Override
public long absoluteTimeMillis() {
return System.currentTimeMillis();
}
@Override
public long relativeTimeMillis() {
return System.nanoTime() / 1_000_000;
}
@Override
public long relativeTimeNanos() {
return System.nanoTime();
}
// ------------------------------------------------------------------------
private SystemClock() {}
}