/**
* 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.jstorm.common.metric;
import com.codahale.metrics.Gauge;
/**
*
* @author zhongyan.feng
* @version $Id:
*/
public class TimerRatio implements Gauge<Double> {
private long lastUpdateTime = 0;
private long sum = 0;
private long lastGaugeTime = 0;
public synchronized void start() {
if (lastUpdateTime == 0) {
lastUpdateTime = System.nanoTime();
}
}
public synchronized void stop() {
if (lastUpdateTime != 0) {
long now = System.nanoTime();
long cost = now - lastUpdateTime;
lastUpdateTime = 0;
sum += cost;
}
}
@Override
public Double getValue() {
synchronized (this) {
stop();
long now = System.nanoTime();
long cost = now - lastGaugeTime;
if (cost == 0) {
return 1.0;
}
lastGaugeTime = now;
double ratio = ((double) sum) / cost;
sum = 0;
return ratio;
}
}
}