com.alibaba.metrics.Timer 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.io.Closeable;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
/**
* A timer metric which aggregates timing durations and provides duration statistics, plus
* throughput statistics via {@link Meter}.
* Timer相当于Meter+Histogram的组合，同时统计一段代码，一个方法的qps，以及执行时间的分布情况
*/
public interface Timer extends Metered, Sampling {
/**
* A timing context.
*
* @see Timer#time()
*/
interface Context extends Closeable {
/**
* Updates the timer with the difference between current and start time. Call to this method will
* not reset the start time. Multiple calls result in multiple updates.
* @return the elapsed time in nanoseconds
*/
long stop();
}
/**
* Adds a recorded duration.
*
* @param duration the length of the duration
* @param unit the scale unit of {@code duration}
*/
void update(long duration, TimeUnit unit);
/**
* Times and records the duration of event.
*
* @param event a {@link Callable} whose {@link Callable#call()} method implements a process
* whose duration should be timed
* @param the type of the value returned by {@code event}
* @return the value returned by {@code event}
* @throws Exception if {@code event} throws an {@link Exception}
*/
T time(Callable event) throws Exception;
/**
* Returns a new {@link Context}.
*
* @return a new {@link Context}
* @see Context
*/
Context time();
}