org.apache.datasketches

Class GenericInequalitySearch

java.lang.Object

org.apache.datasketches.GenericInequalitySearch

public class GenericInequalitySearch
extends Object

This provides efficient, unique and unambiguous binary searching for inequalities for ordered arrays of increasing values that may include duplicate values. These inequalities include <, ≤, ==, ≥, >. The same search method can be used for all these inequalities.

In order to make the searching unique and unambiguous, we modified the traditional binary search algorithm to search for adjacent pairs of values {A, B} in the values array instead of just a single value, where A and B are the array indices of two adjacent values in the array. We then define the searching criteria, given an array of values arr[] and the search key value v.

Author:

Lee Rhodes

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericInequalitySearch.Inequality The enumerator of inequalities

Constructor Summary

Constructors

Constructor and Description
GenericInequalitySearch()

Method Summary

Modifier and Type	Method and Description
static <T> int	find(T[] arr, int low, int high, T v, GenericInequalitySearch.Inequality inequality, Comparator<T> comparator) Binary Search for the index of the generic value in the given search range that satisfies the given inequality.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GenericInequalitySearch

public GenericInequalitySearch()

Method Detail

find

public static <T> int find(T[] arr,
                           int low,
                           int high,
                           T v,
                           GenericInequalitySearch.Inequality inequality,
                           Comparator<T> comparator)

Binary Search for the index of the generic value in the given search range that satisfies the given inequality. If -1 is returned there are no values in the search range that satisfy the inequality.

Type Parameters:

T - The generic type of value to be used in the search process.

Parameters:

arr - the given array that must be sorted with increasing values, must not be null, and must not contain null values in the given range {low, high} inclusive.

low - the lowest index of the lowest value in the search range, inclusive.

high - the highest index of the highest value in the search range, inclusive.

v - the value to search for. It must not be null.

inequality - one of LT, LE, EQ, GE, GT. It must not be null.

comparator - for the type T. It must not be null.

Returns:

the index of the value in the given search range that satisfies the inequality.