// Copyright 2016 The Bazel Authors. All Rights Reserved.
//
// 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.google.testing.junit.runner.util;
/**
* A time source; returns a time value representing the number of nanoseconds elapsed since some
* fixed but arbitrary point in time.
*
* <p><b>Warning:</b> this interface can only be used to measure elapsed time, not wall time.
*/
public abstract class Ticker {
/**
* Constructor for use by subclasses.
*/
protected Ticker() {}
/**
* Returns the number of nanoseconds elapsed since this ticker's fixed point of reference.
*/
public abstract long read();
/**
* A ticker that reads the current time using {@link System#nanoTime}.
*
* @since 10.0
*/
public static Ticker systemTicker() {
return SYSTEM_TICKER;
}
private static final Ticker SYSTEM_TICKER =
new Ticker() {
@Override
public long read() {
return System.nanoTime();
}
};
}