com.netflix.servo.monitor.DoubleCounter Maven / Gradle / Ivy
/*
* Copyright 2011-2018 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.servo.monitor;
import com.netflix.servo.SpectatorContext;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.tag.TagList;
import com.netflix.servo.util.Clock;
import com.netflix.servo.util.VisibleForTesting;
import com.netflix.spectator.api.Id;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicLong;
/**
* A simple counter implementation backed by a StepLong but using doubles.
* The value returned is a rate for the
* previous interval as defined by the step.
*/
class DoubleCounter extends AbstractMonitor
implements NumericMonitor, SpectatorMonitor {
private final MonitorConfig baseConfig;
private final StepLong count;
private final SpectatorContext.LazyCounter spectatorCounter;
/**
* 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));
this.baseConfig = config;
count = new StepLong(0L, clock);
spectatorCounter = SpectatorContext.counter(config);
}
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) {
spectatorCounter.add(amount);
if (amount >= 0.0) {
for (int i = 0; i < Pollers.NUM_POLLERS; ++i) {
add(count.getCurrent(i), amount);
}
}
}
@Override
public Number getValue(int pollerIndex) {
final long n = count.poll(pollerIndex);
final double stepSeconds = Pollers.POLLING_INTERVALS[pollerIndex] / 1000.0;
return Double.longBitsToDouble(n) / stepSeconds;
}
/**
* Get the current count for the given poller index.
*/
@VisibleForTesting
public double getCurrentCount(int pollerIndex) {
return Double.longBitsToDouble(count.getCurrent(pollerIndex).get());
}
/**
* {@inheritDoc}
*/
@Override
public void initializeSpectator(TagList tags) {
Id id = SpectatorContext.createId(baseConfig.withAdditionalTags(tags));
spectatorCounter.setId(id);
}
@Override
public String toString() {
return "DoubleCounter{"
+ "config=" + config
+ "count=" + Double.longBitsToDouble(count.getCurrent(0).longValue())
+ '}';
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
DoubleCounter that = (DoubleCounter) o;
return config.equals(that.config) && Objects.equals(getValue(0), that.getValue(0));
}
@Override
public int hashCode() {
return Objects.hash(config, getValue(0));
}
}