1   /*
2    * Copyright (C) 2009 The Guava Authors
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5    * in compliance with the License. You may obtain a copy of the License at
6    *
7    * http://www.apache.org/licenses/LICENSE-2.0
8    *
9    * Unless required by applicable law or agreed to in writing, software distributed under the
10   * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
11   * express or implied. See the License for the specific language governing permissions and
12   * limitations under the License.
13   */
14  
15  package com.google.common.collect;
16  
17  import com.google.common.annotations.GwtCompatible;
18  import com.google.common.annotations.GwtIncompatible;
19  
20  import java.util.Comparator;
21  
22  import javax.annotation.Nullable;
23  
24  /**
25   * List returned by {@code ImmutableSortedSet.asList()} when the set isn't empty.
26   *
27   * @author Jared Levy
28   * @author Louis Wasserman
29   */
30  @GwtCompatible(emulated = true)
31  @SuppressWarnings("serial")
32  final class ImmutableSortedAsList<E> extends RegularImmutableAsList<E>
33      implements SortedIterable<E> {
34    ImmutableSortedAsList(
35        ImmutableSortedSet<E> backingSet, ImmutableList<E> backingList) {
36      super(backingSet, backingList);
37    }
38  
39    @Override
40    ImmutableSortedSet<E> delegateCollection() {
41      return (ImmutableSortedSet<E>) super.delegateCollection();
42    }
43  
44    @Override public Comparator<? super E> comparator() {
45      return delegateCollection().comparator();
46    }
47  
48    // Override indexOf() and lastIndexOf() to be O(log N) instead of O(N).
49  
50    @GwtIncompatible("ImmutableSortedSet.indexOf")
51    // TODO(cpovirk): consider manual binary search under GWT to preserve O(log N) lookup
52    @Override public int indexOf(@Nullable Object target) {
53      int index = delegateCollection().indexOf(target);
54  
55      // TODO(kevinb): reconsider if it's really worth making feeble attempts at
56      // sanity for inconsistent comparators.
57  
58      // The equals() check is needed when the comparator isn't compatible with
59      // equals().
60      return (index >= 0 && get(index).equals(target)) ? index : -1;
61    }
62  
63    @GwtIncompatible("ImmutableSortedSet.indexOf")
64    @Override public int lastIndexOf(@Nullable Object target) {
65      return indexOf(target);
66    }
67  
68    @Override
69    public boolean contains(Object target) {
70      // Necessary for ISS's with comparators inconsistent with equals.
71      return indexOf(target) >= 0;
72    }
73  
74    @GwtIncompatible("super.subListUnchecked does not exist; inherited subList is valid if slow")
75    /*
76     * TODO(cpovirk): if we start to override indexOf/lastIndexOf under GWT, we'll want some way to
77     * override subList to return an ImmutableSortedAsList for better performance. Right now, I'm not
78     * sure there's any performance hit from our failure to override subListUnchecked under GWT
79     */
80    @Override
81    ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
82      return new RegularImmutableSortedSet<E>(
83          super.subListUnchecked(fromIndex, toIndex), comparator())
84          .asList();
85    }
86  }