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/*
* Licensed to Ted Dunning 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 org.apache.dubbo.metrics.aggregate;
import com.tdunning.math.stats.Centroid;
import com.tdunning.math.stats.TDigest;
public abstract class DubboAbstractTDigest extends TDigest {
boolean recordAllData = false;
/**
* Same as {@link #weightedAverageSorted(double, double, double, double)} but flips
* the order of the variables if x2
is greater than
* x1
.
*/
static double weightedAverage(double x1, double w1, double x2, double w2) {
if (x1 <= x2) {
return weightedAverageSorted(x1, w1, x2, w2);
} else {
return weightedAverageSorted(x2, w2, x1, w1);
}
}
/**
* Compute the weighted average between x1
with a weight of
* w1
and x2
with a weight of w2
.
* This expects x1
to be less than or equal to x2
* and is guaranteed to return a number in [x1, x2]
. An
* explicit check is required since this isn't guaranteed with floating-point
* numbers.
*/
private static double weightedAverageSorted(double x1, double w1, double x2, double w2) {
assert x1 <= x2;
final double x = (x1 * w1 + x2 * w2) / (w1 + w2);
return Math.max(x1, Math.min(x, x2));
}
abstract void add(double x, int w, Centroid base);
/**
* Sets up so that all centroids will record all data assigned to them. For testing only, really.
*/
@Override
public TDigest recordAllData() {
recordAllData = true;
return this;
}
@Override
public boolean isRecording() {
return recordAllData;
}
/**
* Adds a sample to a histogram.
*
* @param x The value to add.
*/
@Override
public void add(double x) {
add(x, 1);
}
@Override
public void add(TDigest other) {
for (Centroid centroid : other.centroids()) {
add(centroid.mean(), centroid.count(), centroid);
}
}
}