| /* |
| * Copyright (C) 2011 The Guava Authors |
| * |
| * Licensed 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. |
| */ |
| |
| package com.google.common.collect; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import com.google.common.annotations.GwtCompatible; |
| import java.util.Comparator; |
| import java.util.SortedSet; |
| |
| /** |
| * Utilities for dealing with sorted collections of all types. |
| * |
| * @author Louis Wasserman |
| */ |
| @GwtCompatible |
| final class SortedIterables { |
| private SortedIterables() {} |
| |
| /** |
| * Returns {@code true} if {@code elements} is a sorted collection using an ordering equivalent to |
| * {@code comparator}. |
| */ |
| public static boolean hasSameComparator(Comparator<?> comparator, Iterable<?> elements) { |
| checkNotNull(comparator); |
| checkNotNull(elements); |
| Comparator<?> comparator2; |
| if (elements instanceof SortedSet) { |
| comparator2 = comparator((SortedSet<?>) elements); |
| } else if (elements instanceof SortedIterable) { |
| comparator2 = ((SortedIterable<?>) elements).comparator(); |
| } else { |
| return false; |
| } |
| return comparator.equals(comparator2); |
| } |
| |
| @SuppressWarnings("unchecked") |
| // if sortedSet.comparator() is null, the set must be naturally ordered |
| public static <E> Comparator<? super E> comparator(SortedSet<E> sortedSet) { |
| Comparator<? super E> result = sortedSet.comparator(); |
| if (result == null) { |
| result = (Comparator<? super E>) Ordering.natural(); |
| } |
| return result; |
| } |
| } |