org.apache.lucene.search.grouping.DoubleRangeFactory Maven / Gradle / Ivy
/*
* 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.lucene.search.grouping;
/** Groups double values into ranges */
public class DoubleRangeFactory {
private final double min;
private final double width;
private final double max;
/**
* Creates a new DoubleRangeFactory
*
* @param min a minimum value; all doubles below this value are grouped into a single range
* @param width a standard width; all ranges between {@code min} and {@code max} are this wide,
* with the exception of the final range which may be up to this width. Ranges are inclusive
* at the lower end, and exclusive at the upper end.
* @param max a maximum value; all doubles above this value are grouped into a single range
*/
public DoubleRangeFactory(double min, double width, double max) {
this.min = min;
this.width = width;
this.max = max;
}
/**
* Finds the DoubleRange that a value should be grouped into
*
* @param value the value to group
* @param reuse an existing DoubleRange object to reuse
*/
public DoubleRange getRange(double value, DoubleRange reuse) {
if (reuse == null) {
reuse = new DoubleRange(Double.MIN_VALUE, Double.MAX_VALUE);
}
if (value < min) {
reuse.max = min;
reuse.min = Double.MIN_VALUE;
return reuse;
}
if (value >= max) {
reuse.min = max;
reuse.max = Double.MAX_VALUE;
return reuse;
}
double bucket = Math.floor((value - min) / width);
reuse.min = min + (bucket * width);
reuse.max = reuse.min + width;
return reuse;
}
}