com.netflix.spectator.servo.DoubleCounter Maven / Gradle / Ivy
/*
* Copyright 2014-2019 Netflix, Inc.
*
* 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.netflix.spectator.servo;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.monitor.AbstractMonitor;
import com.netflix.servo.monitor.MonitorConfig;
import com.netflix.servo.monitor.NumericMonitor;
import com.netflix.servo.util.Clock;
import com.netflix.servo.util.ClockWithOffset;
import java.util.concurrent.atomic.AtomicLong;
/**
* A simple counter implementation backed by a StepLong. The value returned is a rate for the
* previous interval as defined by the step.
*/
class DoubleCounter extends AbstractMonitor implements NumericMonitor {
private final StepLong count;
/**
* Creates a new instance of the counter.
*/
DoubleCounter(MonitorConfig config) {
this(config, ClockWithOffset.INSTANCE);
}
/**
* Creates a new instance of the counter.
*/
DoubleCounter(MonitorConfig config, Clock clock) {
// This class will reset the value so it is not a monotonically increasing value as
// expected for type=COUNTER. This class looks like a counter to the user and a gauge to
// the publishing pipeline receiving the value.
super(config.withAdditionalTag(DataSourceType.NORMALIZED));
count = new StepLong(0L, clock);
}
private void add(AtomicLong num, double amount) {
long v;
double d;
long next;
do {
v = num.get();
d = Double.longBitsToDouble(v);
next = Double.doubleToLongBits(d + amount);
} while (!num.compareAndSet(v, next));
}
/**
* Increment the value by the specified amount.
*/
void increment(double amount) {
if (amount >= 0.0) {
for (int i = 0; i < ServoPollers.NUM_POLLERS; ++i) {
add(count.getCurrent(i), amount);
}
}
}
@Override public Number getValue(int pollerIndex) {
final Long dp = count.poll(pollerIndex);
final double stepSeconds = ServoPollers.POLLING_INTERVALS[pollerIndex] / 1000.0;
return (dp == null) ? Double.NaN : Double.longBitsToDouble(dp) / stepSeconds;
}
@Override public String toString() {
return "DoubleCounter(config=" + config + ",count=" + getValue() + ")";
}
}