io.github.bucket4j.TimeMeter Maven / Gradle / Ivy
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/*-
* ========================LICENSE_START=================================
* Bucket4j
* %%
* Copyright (C) 2015 - 2020 Vladimir Bukhtoyarov
* %%
* 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.
* =========================LICENSE_END==================================
*/
package io.github.bucket4j;
import java.util.concurrent.TimeUnit;
/**
* An abstraction over time measurement.
*
* @see TimeMeter#SYSTEM_NANOTIME
* @see TimeMeter#SYSTEM_MILLISECONDS
*/
public interface TimeMeter {
/**
* Returns current time in nanosecond precision, but not necessarily nanosecond resolution.
*
* @return current time in nanoseconds
*/
long currentTimeNanos();
/**
* Returns {@code true} if implementation of clock behaves the similar way as {@link System#currentTimeMillis()},
* in other words if implementation can be used in distributed scenarios
* and returns approximately the same time in all machines in cluster
*
* @return {@code true} if implementation can be used as wall clock
*/
boolean isWallClockBased();
/**
* The implementation of {@link TimeMeter} which works around {@link java.lang.System#nanoTime}
*/
TimeMeter SYSTEM_NANOTIME = new TimeMeter() {
@Override
public long currentTimeNanos() {
return System.nanoTime();
}
@Override
public boolean isWallClockBased() {
return false;
}
@Override
public String toString() {
return "SYSTEM_NANOTIME";
}
};
/**
* The implementation of {@link TimeMeter} which works around {@link java.lang.System#currentTimeMillis}
*/
TimeMeter SYSTEM_MILLISECONDS = new TimeMeter() {
@Override
public long currentTimeNanos() {
long nowMillis = System.currentTimeMillis();
return TimeUnit.MILLISECONDS.toNanos(nowMillis);
}
@Override
public boolean isWallClockBased() {
return true;
}
@Override
public String toString() {
return "SYSTEM_MILLISECONDS";
}
};
}