org.apache.lucene.util

Class CollectionUtil

java.lang.Object

org.apache.lucene.util.CollectionUtil

public final class CollectionUtil
extends java.lang.Object

Methods for manipulating (sorting) collections. Sort methods work directly on the supplied lists and don't copy to/from arrays before/after. For medium size collections as used in the Lucene indexer that is much more efficient.

Method Summary

Modifier and Type	Method and Description
static <T extends java.lang.Comparable<? super T>> void	introSort(java.util.List<T> list) Sorts the given random access List in natural order.
static <T> void	introSort(java.util.List<T> list, java.util.Comparator<? super T> comp) Sorts the given random access List using the Comparator.
static <T extends java.lang.Comparable<? super T>> void	timSort(java.util.List<T> list) Sorts the given random access List in natural order.
static <T> void	timSort(java.util.List<T> list, java.util.Comparator<? super T> comp) Sorts the given random access List using the Comparator.

Methods inherited from class java.lang.Object

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

Method Detail

introSort

public static <T> void introSort(java.util.List<T> list,
                                 java.util.Comparator<? super T> comp)

Sorts the given random access List using the Comparator. The list must implement RandomAccess. This method uses the intro sort algorithm, but falls back to insertion sort for small lists.

Throws:

java.lang.IllegalArgumentException - if list is e.g. a linked list without random access.

introSort

public static <T extends java.lang.Comparable<? super T>> void introSort(java.util.List<T> list)

Sorts the given random access List in natural order. The list must implement RandomAccess. This method uses the intro sort algorithm, but falls back to insertion sort for small lists.

Throws:

java.lang.IllegalArgumentException - if list is e.g. a linked list without random access.

timSort

public static <T> void timSort(java.util.List<T> list,
                               java.util.Comparator<? super T> comp)

Sorts the given random access List using the Comparator. The list must implement RandomAccess. This method uses the Tim sort algorithm, but falls back to binary sort for small lists.

Throws:

java.lang.IllegalArgumentException - if list is e.g. a linked list without random access.

timSort

public static <T extends java.lang.Comparable<? super T>> void timSort(java.util.List<T> list)

Sorts the given random access List in natural order. The list must implement RandomAccess. This method uses the Tim sort algorithm, but falls back to binary sort for small lists.

Throws:

java.lang.IllegalArgumentException - if list is e.g. a linked list without random access.