1 /* 2 * Copyright 2017, OpenCensus Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.opencensus.stats; 18 19 import com.google.auto.value.AutoValue; 20 import io.opencensus.internal.Utils; 21 import java.util.ArrayList; 22 import java.util.Collections; 23 import java.util.List; 24 import javax.annotation.concurrent.Immutable; 25 26 /** 27 * The bucket boundaries for a histogram. 28 * 29 * @since 0.8 30 */ 31 @Immutable 32 @AutoValue 33 public abstract class BucketBoundaries { 34 35 /** 36 * Returns a {@code BucketBoundaries} with the given buckets. 37 * 38 * @param bucketBoundaries the boundaries for the buckets in the underlying histogram. 39 * @return a new {@code BucketBoundaries} with the specified boundaries. 40 * @throws NullPointerException if {@code bucketBoundaries} is null. 41 * @throws IllegalArgumentException if {@code bucketBoundaries} is not sorted. 42 * @since 0.8 43 */ 44 public static final BucketBoundaries create(List<Double> bucketBoundaries) { 45 Utils.checkNotNull(bucketBoundaries, "bucketBoundaries"); 46 List<Double> bucketBoundariesCopy = new ArrayList<Double>(bucketBoundaries); // Deep copy. 47 // Check if sorted. 48 if (bucketBoundariesCopy.size() > 1) { 49 double lower = bucketBoundariesCopy.get(0); 50 for (int i = 1; i < bucketBoundariesCopy.size(); i++) { 51 double next = bucketBoundariesCopy.get(i); 52 Utils.checkArgument(lower < next, "Bucket boundaries not sorted."); 53 lower = next; 54 } 55 } 56 return new AutoValue_BucketBoundaries(Collections.unmodifiableList(bucketBoundariesCopy)); 57 } 58 59 /** 60 * Returns a list of histogram bucket boundaries. 61 * 62 * @return a list of histogram bucket boundaries. 63 * @since 0.8 64 */ 65 public abstract List<Double> getBoundaries(); 66 } 67