UnmodifiableSortedMultiset.java revision 3ecfa412eddc4b084663f38d562537b86b9734d5 
1/*
2 * Copyright (C) 2012 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect;
18
19import com.google.common.annotations.GwtCompatible;
20import com.google.common.collect.Multisets.UnmodifiableMultiset;
21
22import java.util.Comparator;
23import java.util.NavigableSet;
24
25/**
26 * Implementation of {@link Multisets#unmodifiableSortedMultiset(SortedMultiset)},
27 * split out into its own file so it can be GWT emulated (to deal with the differing
28 * elementSet() types in GWT and non-GWT).
29 *
30 * @author Louis Wasserman
31 */
32@GwtCompatible(emulated = true)
33final class UnmodifiableSortedMultiset<E>
34    extends UnmodifiableMultiset<E> implements SortedMultiset<E> {
35  UnmodifiableSortedMultiset(SortedMultiset<E> delegate) {
36    super(delegate);
37  }
38
39  @Override
40  protected SortedMultiset<E> delegate() {
41    return (SortedMultiset<E>) super.delegate();
42  }
43
44  @Override
45  public Comparator<? super E> comparator() {
46    return delegate().comparator();
47  }
48
49  @Override
50  NavigableSet<E> createElementSet() {
51    return Sets.unmodifiableNavigableSet(delegate().elementSet());
52  }
53
54  @Override
55  public NavigableSet<E> elementSet() {
56    return (NavigableSet<E>) super.elementSet();
57  }
58
59  private transient UnmodifiableSortedMultiset<E> descendingMultiset;
60
61  @Override
62  public SortedMultiset<E> descendingMultiset() {
63    UnmodifiableSortedMultiset<E> result = descendingMultiset;
64    if (result == null) {
65      result = new UnmodifiableSortedMultiset<E>(
66          delegate().descendingMultiset());
67      result.descendingMultiset = this;
68      return descendingMultiset = result;
69    }
70    return result;
71  }
72
73  @Override
74  public Entry<E> firstEntry() {
75    return delegate().firstEntry();
76  }
77
78  @Override
79  public Entry<E> lastEntry() {
80    return delegate().lastEntry();
81  }
82
83  @Override
84  public Entry<E> pollFirstEntry() {
85    throw new UnsupportedOperationException();
86  }
87
88  @Override
89  public Entry<E> pollLastEntry() {
90    throw new UnsupportedOperationException();
91  }
92
93  @Override
94  public SortedMultiset<E> headMultiset(E upperBound, BoundType boundType) {
95    return Multisets.unmodifiableSortedMultiset(
96        delegate().headMultiset(upperBound, boundType));
97  }
98
99  @Override
100  public SortedMultiset<E> subMultiset(
101      E lowerBound, BoundType lowerBoundType,
102      E upperBound, BoundType upperBoundType) {
103    return Multisets.unmodifiableSortedMultiset(delegate().subMultiset(
104        lowerBound, lowerBoundType, upperBound, upperBoundType));
105  }
106
107  @Override
108  public SortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType) {
109    return Multisets.unmodifiableSortedMultiset(
110        delegate().tailMultiset(lowerBound, boundType));
111  }
112
113  private static final long serialVersionUID = 0;
114}