1 /***********************************************************************
2  * Copyright (c) 2013-2024 Commonwealth Computer Research, Inc.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Apache License, Version 2.0
5  * which accompanies this distribution and is available at
6  * http://www.opensource.org/licenses/apache2.0.php.
7  ***********************************************************************/
8 
9 package org.locationtech.geomesa.utils.stats
10 
11 import org.geotools.api.feature.simple.{SimpleFeature, SimpleFeatureType}
12 
13 import scala.collection.immutable.ListMap
14 import scala.reflect.ClassTag
15 
16 /**
17   * An enumeration is merely a HashMap mapping values to number of occurrences
18   *
19   * @param sft simple feature type
20   * @param property property name the enumeration is being made for
21   * @tparam T some type T (which is restricted by the stat parser upstream of Histogram instantiation)
22   */
23 class EnumerationStat[T](val sft: SimpleFeatureType, val property: String)(implicit val ct: ClassTag[T]) extends Stat {
24 
25   override type S = EnumerationStat[T]
26 
27   private val i = sft.indexOf(property)
28   private [stats] val enumeration = scala.collection.mutable.HashMap.empty[T, Long].withDefaultValue(0)
29 
30   def size: Int = enumeration.size
31   def values: Iterable[T] = enumeration.keys
32   def frequency(value: T): Long = enumeration(value)
33   def frequencies: Iterable[(T, Long)] = enumeration
34 
35   override def observe(sf: SimpleFeature): Unit = {
36     val value = sf.getAttribute(i).asInstanceOf[T]
37     if (value != null) {
38       enumeration(value) += 1
39     }
40   }
41 
42   override def unobserve(sf: SimpleFeature): Unit = {
43     val value = sf.getAttribute(i).asInstanceOf[T]
44     if (value != null) {
45       val current = enumeration(value)
46       if (current == 1) {
47         enumeration.remove(value)
48       } else {
49         enumeration(value) = current - 1
50       }
51     }
52   }
53 
54   override def +(other: EnumerationStat[T]): EnumerationStat[T] = {
55     val plus = new EnumerationStat[T](sft, property)
56     plus += this
57     plus += other
58     plus
59   }
60 
61   override def +=(other: EnumerationStat[T]): Unit =
62     other.enumeration.foreach { case (key, count) => enumeration(key) += count }
63 
64   override def toJsonObject: Map[T, Long] =
65     if (enumeration.isEmpty) { Map.empty } else { ListMap(enumeration.toSeq.sortBy(_.toString):_*) }
66 
67   override def isEmpty: Boolean = enumeration.isEmpty
68 
69   override def clear(): Unit = enumeration.clear()
70 
71   override def isEquivalent(other: Stat): Boolean = other match {
72     case that: EnumerationStat[_] => property == that.property && enumeration == that.enumeration
73     case _ => false
74   }
75 }