ImmutableAsList.java revision 7dd252788645e940eada959bdde927426e2531c9 
1/*
2 * Copyright (C) 2009 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.annotations.GwtIncompatible;
21
22import java.io.InvalidObjectException;
23import java.io.ObjectInputStream;
24import java.io.Serializable;
25
26/**
27 * List returned by {@link ImmutableCollection#asList} that delegates {@code contains} checks
28 * to the backing collection.
29 *
30 * @author Jared Levy
31 * @author Louis Wasserman
32 */
33@GwtCompatible(serializable = true, emulated = true)
34@SuppressWarnings("serial")
35abstract class ImmutableAsList<E> extends ImmutableList<E> {
36  abstract ImmutableCollection<E> delegateCollection();
37
38  @Override
39  public boolean contains(Object target) {
40    // The collection's contains() is at least as fast as ImmutableList's
41    // and is often faster.
42    return delegateCollection().contains(target);
43  }
44
45  public int size() {
46    return delegateCollection().size();
47  }
48
49  @Override
50  public boolean isEmpty() {
51    return delegateCollection().isEmpty();
52  }
53
54  @Override
55  boolean isPartialView() {
56    return delegateCollection().isPartialView();
57  }
58
59  /**
60   * Serialized form that leads to the same performance as the original list.
61   */
62  @GwtIncompatible("serialization")
63  static class SerializedForm implements Serializable {
64    final ImmutableCollection<?> collection;
65
66    SerializedForm(ImmutableCollection<?> collection) {
67      this.collection = collection;
68    }
69
70    Object readResolve() {
71      return collection.asList();
72    }
73
74    private static final long serialVersionUID = 0;
75  }
76
77  @GwtIncompatible("serialization")
78  private void readObject(ObjectInputStream stream) throws InvalidObjectException {
79    throw new InvalidObjectException("Use SerializedForm");
80  }
81
82  @Override
83  @GwtIncompatible("serialization")
84  Object writeReplace() {
85    return new SerializedForm(delegateCollection());
86  }
87}
88