1/*
2 * Copyright (C) 2007 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.VisibleForTesting;
21import com.google.common.collect.ImmutableSet.ArrayImmutableSet;
22
23/**
24 * Implementation of {@link ImmutableSet} with two or more elements.
25 *
26 * @author Kevin Bourrillion
27 */
28@GwtCompatible(serializable = true, emulated = true)
29@SuppressWarnings("serial") // uses writeReplace(), not default serialization
30final class RegularImmutableSet<E> extends ArrayImmutableSet<E> {
31  // the same elements in hashed positions (plus nulls)
32  @VisibleForTesting final transient Object[] table;
33  // 'and' with an int to get a valid table index.
34  private final transient int mask;
35  private final transient int hashCode;
36
37  RegularImmutableSet(
38      Object[] elements, int hashCode, Object[] table, int mask) {
39    super(elements);
40    this.table = table;
41    this.mask = mask;
42    this.hashCode = hashCode;
43  }
44
45  @Override public boolean contains(Object target) {
46    if (target == null) {
47      return false;
48    }
49    for (int i = Hashing.smear(target.hashCode()); true; i++) {
50      Object candidate = table[i & mask];
51      if (candidate == null) {
52        return false;
53      }
54      if (candidate.equals(target)) {
55        return true;
56      }
57    }
58  }
59
60  @Override public int hashCode() {
61    return hashCode;
62  }
63
64  @Override boolean isHashCodeFast() {
65    return true;
66  }
67}
68