/*
 * 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
/**
 * Groups double values into ranges
 */
public class DoubleRangeFactory {

  private final double min;
  private final double width;
  private final double max;

  
Creates a new DoubleRangeFactory
Params:
min –     a minimum value; all doubles below this value are grouped into a single range
width –  a standard width; all ranges between min and 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.
max –     a maximum value; all doubles above this value are grouped into a single range/**
   * 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
Params:
value – the value to group
reuse – an existing DoubleRange object to reuse/**
   * 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;
  }

}