EstimatedHistogramBasedCounter.java

/**
 * Copyright 2016 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.dyno.contrib;

import com.google.common.base.Objects;
import com.netflix.dyno.connectionpool.impl.utils.EstimatedHistogram;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.monitor.AbstractMonitor;
import com.netflix.servo.monitor.MonitorConfig;
import com.netflix.servo.tag.BasicTag;

public abstract class EstimatedHistogramBasedCounter extends AbstractMonitor<Number> {

	protected final EstimatedHistogram estHistogram; 
	
	/**
	 * Creates a new instance of the counter.
	 */
	public EstimatedHistogramBasedCounter(final String name, final String opName, final EstimatedHistogram histogram) {
		super(MonitorConfig.builder(name).build()
				.withAdditionalTag(DataSourceType.GAUGE)
				.withAdditionalTag(new BasicTag("dyno_op", opName)));
		this.estHistogram = histogram;
	}

	public EstimatedHistogramBasedCounter(final String name, final String opName, final String tagName, final EstimatedHistogram histogram) {
		super(MonitorConfig.builder(name).build()
				.withAdditionalTag(DataSourceType.GAUGE)
				.withAdditionalTag(new BasicTag(tagName, opName)));
		this.estHistogram = histogram;
	}
	
	/** {@inheritDoc} */
	@Override
	public boolean equals(Object obj) {
		if (obj == null || !(obj instanceof EstimatedHistogramBasedCounter)) {
			return false;
		}
		EstimatedHistogramBasedCounter m = (EstimatedHistogramBasedCounter) obj;
		return config.equals(m.getConfig()) && estHistogram.equals(m.estHistogram);
	}

	/** {@inheritDoc} */
	@Override
	public int hashCode() {
		return Objects.hashCode(config, estHistogram.hashCode());
	}

	/** {@inheritDoc} */
	@Override
	public String toString() {
		return Objects.toStringHelper(this)
				.add("config", config)
				.add("count", getValue())
				.toString();
	}
	
	public static class EstimatedHistogramMean extends EstimatedHistogramBasedCounter {

		public EstimatedHistogramMean(final String name, final String opName, final EstimatedHistogram histogram) {
			super(name, opName, histogram);
		}

		public EstimatedHistogramMean(final String name, final String opName, final String tagName, final EstimatedHistogram histogram) {
			super(name, opName, tagName, histogram);
		}

		@Override
		public Number getValue() {
			return estHistogram.mean();
		}

		public void add(long n) {
            this.estHistogram.add(n);
        }

        public void reset() {
            this.estHistogram.getBuckets(true);
        }
	}

	public static class EstimatedHistogramPercentile extends EstimatedHistogramBasedCounter {

		private final double percentile;
		
		public EstimatedHistogramPercentile(final String name, final String opName, final EstimatedHistogram histogram, double pVal) {
			super(name, opName, histogram);
			percentile = pVal;
		}

		public EstimatedHistogramPercentile(final String name, final String opName, final String tagName, final EstimatedHistogram histogram, double pVal) {
			super(name, opName, tagName, histogram);
			percentile = pVal;
		}

		@Override
		public Number getValue() {
			return estHistogram.percentile(percentile);
		}
	}
}