blob: 2c36bb10acf4afa3322d2b04fa9928876e79b7f1 [file] [log] [blame]
/*
* Licensed to the Apache Software Foundation (ASF) 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.datasketches.quantilescommon;
import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.INCLUSIVE;
/**
* This enables the special functions for performing efficient partitioning of massive data.
*/
public interface PartitioningFeature<T> {
/**
* This method returns an instance of
* {@link GenericPartitionBoundaries GenericPartitionBoundaries} which provides
* sufficient information for the user to create the given number of equally sized partitions, where "equally sized"
* refers to an approximately equal number of items per partition.
*
* <p>This method is equivalent to
* {@link #getPartitionBoundaries(int, QuantileSearchCriteria) getPartitionBoundaries(numEquallySized, INCLUSIVE)}.
* </p>
*
* @param numEquallySized an integer that specifies the number of equally sized partitions between
* {@link GenericPartitionBoundaries#getMinItem() getMinItem()} and
* {@link GenericPartitionBoundaries#getMaxItem() getMaxItem()}.
* This must be a positive integer greater than zero.
* <ul>
* <li>A 1 will return: minItem, maxItem.</li>
* <li>A 2 will return: minItem, median quantile, maxItem.</li>
* <li>Etc.</li>
* </ul>
*
* @return an instance of {@link GenericPartitionBoundaries GenericPartitionBoundaries}.
* @throws IllegalArgumentException if sketch is empty.
* @throws IllegalArgumentException if <i>numEquallySized</i> is less than 1.
*/
default GenericPartitionBoundaries<T> getPartitionBoundaries(int numEquallySized) {
return getPartitionBoundaries(numEquallySized, INCLUSIVE);
}
/**
* This method returns an instance of
* {@link GenericPartitionBoundaries GenericPartitionBoundaries} which provides
* sufficient information for the user to create the given number of equally sized partitions, where "equally sized"
* refers to an approximately equal number of items per partition.
*
* @param numEquallySized an integer that specifies the number of equally sized partitions between
* {@link GenericPartitionBoundaries#getMinItem() getMinItem()} and
* {@link GenericPartitionBoundaries#getMaxItem() getMaxItem()}.
* This must be a positive integer greater than zero.
* <ul>
* <li>A 1 will return: minItem, maxItem.</li>
* <li>A 2 will return: minItem, median quantile, maxItem.</li>
* <li>Etc.</li>
* </ul>
*
* @param searchCrit
* If INCLUSIVE, all the returned quantiles are the upper boundaries of the equally sized partitions
* with the exception of the lowest returned quantile, which is the lowest boundary of the lowest ranked partition.
* If EXCLUSIVE, all the returned quantiles are the lower boundaries of the equally sized partitions
* with the exception of the highest returned quantile, which is the upper boundary of the highest ranked partition.
*
* @return an instance of {@link GenericPartitionBoundaries GenericPartitionBoundaries}.
* @throws IllegalArgumentException if sketch is empty.
* @throws IllegalArgumentException if <i>numEquallySized</i> is less than 1.
*/
GenericPartitionBoundaries<T> getPartitionBoundaries(int numEquallySized, QuantileSearchCriteria searchCrit);
}