+++ /dev/null
-package org.apache.lucene.util;
-
-/**
- * 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.
- */
-
-import java.util.Comparator;
-import java.util.Collections;
-import java.util.List;
-import java.util.RandomAccess;
-
-/**
- * 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.
- *
- * @lucene.internal
- */
-
-public final class CollectionUtil {
-
- private CollectionUtil() {} // no instance
-
- /** SorterTemplate with custom {@link Comparator} */
- private static <T> SorterTemplate getSorter(final List<T> list, final Comparator<? super T> comp) {
- if (!(list instanceof RandomAccess))
- throw new IllegalArgumentException("CollectionUtil can only sort random access lists in-place.");
- return new SorterTemplate() {
- @Override
- protected void swap(int i, int j) {
- Collections.swap(list, i, j);
- }
-
- @Override
- protected int compare(int i, int j) {
- return comp.compare(list.get(i), list.get(j));
- }
-
- @Override
- protected void setPivot(int i) {
- pivot = list.get(i);
- }
-
- @Override
- protected int comparePivot(int j) {
- return comp.compare(pivot, list.get(j));
- }
-
- private T pivot;
- };
- }
-
- /** Natural SorterTemplate */
- private static <T extends Comparable<? super T>> SorterTemplate getSorter(final List<T> list) {
- if (!(list instanceof RandomAccess))
- throw new IllegalArgumentException("CollectionUtil can only sort random access lists in-place.");
- return new SorterTemplate() {
- @Override
- protected void swap(int i, int j) {
- Collections.swap(list, i, j);
- }
-
- @Override
- protected int compare(int i, int j) {
- return list.get(i).compareTo(list.get(j));
- }
-
- @Override
- protected void setPivot(int i) {
- pivot = list.get(i);
- }
-
- @Override
- protected int comparePivot(int j) {
- return pivot.compareTo(list.get(j));
- }
-
- private T pivot;
- };
- }
-
- /**
- * Sorts the given random access {@link List} using the {@link Comparator}.
- * The list must implement {@link RandomAccess}. This method uses the quick sort
- * algorithm, but falls back to insertion sort for small lists.
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T> void quickSort(List<T> list, Comparator<? super T> comp) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list, comp).quickSort(0, size-1);
- }
-
- /**
- * Sorts the given random access {@link List} in natural order.
- * The list must implement {@link RandomAccess}. This method uses the quick sort
- * algorithm, but falls back to insertion sort for small lists.
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T extends Comparable<? super T>> void quickSort(List<T> list) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list).quickSort(0, size-1);
- }
-
- // mergeSorts:
-
- /**
- * Sorts the given random access {@link List} using the {@link Comparator}.
- * The list must implement {@link RandomAccess}. This method uses the merge sort
- * algorithm, but falls back to insertion sort for small lists.
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T> void mergeSort(List<T> list, Comparator<? super T> comp) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list, comp).mergeSort(0, size-1);
- }
-
- /**
- * Sorts the given random access {@link List} in natural order.
- * The list must implement {@link RandomAccess}. This method uses the merge sort
- * algorithm, but falls back to insertion sort for small lists.
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T extends Comparable<? super T>> void mergeSort(List<T> list) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list).mergeSort(0, size-1);
- }
-
- // insertionSorts:
-
- /**
- * Sorts the given random access {@link List} using the {@link Comparator}.
- * The list must implement {@link RandomAccess}. This method uses the insertion sort
- * algorithm. It is only recommended to use this algorithm for partially sorted small lists!
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T> void insertionSort(List<T> list, Comparator<? super T> comp) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list, comp).insertionSort(0, size-1);
- }
-
- /**
- * Sorts the given random access {@link List} in natural order.
- * The list must implement {@link RandomAccess}. This method uses the insertion sort
- * algorithm. It is only recommended to use this algorithm for partially sorted small lists!
- * @throws IllegalArgumentException if list is e.g. a linked list without random access.
- */
- public static <T extends Comparable<? super T>> void insertionSort(List<T> list) {
- final int size = list.size();
- if (size <= 1) return;
- getSorter(list).insertionSort(0, size-1);
- }
-
-}
\ No newline at end of file
fnp / pylucene.git / blobdiff