io.opencensus.stats.BucketBoundaries Maven / Gradle / Ivy
/*
* Copyright 2017, OpenCensus Authors
*
* 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 io.opencensus.stats;
import com.google.auto.value.AutoValue;
import io.opencensus.internal.Utils;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.concurrent.Immutable;
/**
* The bucket boundaries for a histogram.
*
* @since 0.8
*/
@Immutable
@AutoValue
public abstract class BucketBoundaries {
private static final Logger logger = Logger.getLogger(BucketBoundaries.class.getName());
/**
* Returns a {@code BucketBoundaries} with the given buckets.
*
* @param bucketBoundaries the boundaries for the buckets in the underlying histogram.
* @return a new {@code BucketBoundaries} with the specified boundaries.
* @throws NullPointerException if {@code bucketBoundaries} is null.
* @throws IllegalArgumentException if {@code bucketBoundaries} is not sorted.
* @since 0.8
*/
public static final BucketBoundaries create(List bucketBoundaries) {
Utils.checkNotNull(bucketBoundaries, "bucketBoundaries");
List bucketBoundariesCopy = new ArrayList(bucketBoundaries); // Deep copy.
// Check if sorted.
if (bucketBoundariesCopy.size() > 1) {
double previous = bucketBoundariesCopy.get(0);
for (int i = 1; i < bucketBoundariesCopy.size(); i++) {
double next = bucketBoundariesCopy.get(i);
Utils.checkArgument(previous < next, "Bucket boundaries not sorted.");
previous = next;
}
}
return new AutoValue_BucketBoundaries(
Collections.unmodifiableList(dropNegativeBucketBounds(bucketBoundariesCopy)));
}
private static List dropNegativeBucketBounds(List bucketBoundaries) {
// Negative values (BucketBounds) are currently not supported by any of the backends
// that OC supports.
int negativeBucketBounds = 0;
int zeroBucketBounds = 0;
for (Double value : bucketBoundaries) {
if (value <= 0) {
if (value == 0) {
zeroBucketBounds++;
} else {
negativeBucketBounds++;
}
} else {
break;
}
}
if (negativeBucketBounds > 0) {
logger.log(
Level.WARNING,
"Dropping "
+ negativeBucketBounds
+ " negative bucket boundaries, the values must be strictly > 0.");
}
return bucketBoundaries.subList(
negativeBucketBounds + zeroBucketBounds, bucketBoundaries.size());
}
/**
* Returns a list of histogram bucket boundaries.
*
* @return a list of histogram bucket boundaries.
* @since 0.8
*/
public abstract List getBoundaries();
}