org.apache.calcite.runtime

Class BinarySearch

java.lang.Object

org.apache.calcite.runtime.BinarySearch

public class BinarySearch
extends Object

Binary search for the implementation of RANGE BETWEEN XXX PRECEDING/FOLLOWING clause.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BinarySearch()

Method Summary

Methods

Modifier and Type	Method and Description
static <T,K> int	lowerBound(T[] a, K key, Function1<T,K> keySelector, Comparator<K> comparator) Performs binary search of the lower bound in the given array.
static <T,K> int	lowerBound(T[] a, K key, int imin, int imax, Function1<T,K> keySelector, Comparator<K> comparator) Taken from http://en.wikipedia.org/wiki/Binary_search_algorithm #Deferred_detection_of_equality
static <T> int	lowerBound(T[] a, T key, Comparator<T> comparator) Performs binary search of the lower bound in the given array.
static <T> int	lowerBound(T[] a, T key, int imin, int imax, Comparator<T> comparator) Performs binary search of the lower bound in the given section of array.
static <T,K> int	upperBound(T[] a, K key, Function1<T,K> keySelector, Comparator<K> comparator) Performs binary search of the upper bound in the given array.
static <T,K> int	upperBound(T[] a, K key, int imin, int imax, Function1<T,K> keySelector, Comparator<K> comparator) Taken from http://en.wikipedia.org/wiki/Binary_search_algorithm #Deferred_detection_of_equality Adapted to find upper bound.
static <T> int	upperBound(T[] a, T key, Comparator<T> comparator) Performs binary search of the upper bound in the given array.
static <T> int	upperBound(T[] a, T key, int imin, int imax, Comparator<T> comparator) Performs binary search of the upper bound in the given array.

Methods inherited from class java.lang.Object

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

Constructor Detail

BinarySearch

protected BinarySearch()

Method Detail

lowerBound

public static <T> int lowerBound(T[] a,
                 T key,
                 Comparator<T> comparator)

Performs binary search of the lower bound in the given array. It is assumed that the array is sorted. The method is guaranteed to return the minimal index of the element that is greater or equal to the given key.

Type Parameters:

T - the type of elements in array

Parameters:

a - array that holds the values

key - element to look for

comparator - comparator that compares keys

Returns:

minimal index of the element that is greater or equal to the given key. Returns -1 when all elements exceed the given key or the array is empty. Returns a.length when all elements are less than the given key.

upperBound

public static <T> int upperBound(T[] a,
                 T key,
                 Comparator<T> comparator)

Performs binary search of the upper bound in the given array. It is assumed that the array is sorted. The method is guaranteed to return the maximal index of the element that is less or equal to the given key.

Type Parameters:

T - the type of elements in array

Parameters:

a - array that holds the values

key - element to look for

comparator - comparator that compares keys

Returns:

maximal index of the element that is less or equal to the given key. Returns -1 when all elements are less than the given key or the array is empty. Returns a.length when all elements exceed the given key.

lowerBound

public static <T,K> int lowerBound(T[] a,
                   K key,
                   Function1<T,K> keySelector,
                   Comparator<K> comparator)

Performs binary search of the lower bound in the given array. The elements in the array are transformed before the comparison. It is assumed that the array is sorted. The method is guaranteed to return the minimal index of the element that is greater or equal to the given key.

Type Parameters:

T - the type of elements in array

K - the type of lookup key

Parameters:

a - array that holds the values

key - element to look for

keySelector - function that transforms array contents to the type of the key

comparator - comparator that compares keys

Returns:

minimal index of the element that is greater or equal to the given key. Returns -1 when all elements exceed the given key or the array is empty. Returns a.length when all elements are less than the given key.

upperBound

public static <T,K> int upperBound(T[] a,
                   K key,
                   Function1<T,K> keySelector,
                   Comparator<K> comparator)

Performs binary search of the upper bound in the given array. The elements in the array are transformed before the comparison. It is assumed that the array is sorted. The method is guaranteed to return the maximal index of the element that is less or equal to the given key.

Type Parameters:

T - the type of elements in array

K - the type of lookup key

Parameters:

a - array that holds the values

key - element to look for

keySelector - function that transforms array contents to the type of the key

comparator - comparator that compares keys

Returns:

maximal index of the element that is less or equal to the given key. Returns -1 when all elements are less than the given key or the array is empty. Returns a.length when all elements exceed the given key.

lowerBound

public static <T> int lowerBound(T[] a,
                 T key,
                 int imin,
                 int imax,
                 Comparator<T> comparator)

Performs binary search of the lower bound in the given section of array. It is assumed that the array is sorted. The method is guaranteed to return the minimal index of the element that is greater or equal to the given key.

Type Parameters:

T - the type of elements in array

Parameters:

a - array that holds the values

key - element to look for

imin - the minimal index (inclusive) to look for

imax - the maximum index (inclusive) to look for

comparator - comparator that compares keys

Returns:

minimal index of the element that is greater or equal to the given key. Returns -1 when all elements exceed the given key or the array is empty. Returns a.length when all elements are less than the given key.

upperBound

public static <T> int upperBound(T[] a,
                 T key,
                 int imin,
                 int imax,
                 Comparator<T> comparator)

Performs binary search of the upper bound in the given array. It is assumed that the array is sorted. The method is guaranteed to return the maximal index of the element that is less or equal to the given key.

Type Parameters:

T - the type of elements in array

Parameters:

a - array that holds the values

key - element to look for

imin - the minimal index (inclusive) to look for

imax - the maximum index (inclusive) to look for

comparator - comparator that compares keys

Returns:

maximal index of the element that is less or equal to the given key. Returns -1 when all elements are less than the given key or the array is empty. Returns a.length when all elements exceed the given key.

lowerBound

public static <T,K> int lowerBound(T[] a,
                   K key,
                   int imin,
                   int imax,
                   Function1<T,K> keySelector,
                   Comparator<K> comparator)

Taken from http://en.wikipedia.org/wiki/Binary_search_algorithm #Deferred_detection_of_equality

upperBound

public static <T,K> int upperBound(T[] a,
                   K key,
                   int imin,
                   int imax,
                   Function1<T,K> keySelector,
                   Comparator<K> comparator)

Taken from http://en.wikipedia.org/wiki/Binary_search_algorithm #Deferred_detection_of_equality Adapted to find upper bound.