Coverage Summary for Class: JdkBackedImmutableMap (com.google.common.collect)

1 /*
2  * Copyright (C) 2018 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 
17 package com.google.common.collect;
18 
19 import static com.google.common.base.Preconditions.checkNotNull;
20 import static com.google.common.collect.RegularImmutableMap.makeImmutable;
21 
22 import com.google.common.annotations.GwtCompatible;
23 import java.util.Map;
24 import java.util.function.BiConsumer;
25 import org.checkerframework.checker.nullness.qual.Nullable;
26 
27 /**
28  * Implementation of ImmutableMap backed by a JDK HashMap, which has smartness protecting against
29  * hash flooding.
30  */
31 @GwtCompatible(emulated = true)
32 final class JdkBackedImmutableMap<K, V> extends ImmutableMap<K, V> {
33   /**
34    * Creates an {@code ImmutableMap} backed by a JDK HashMap. Used when probable hash flooding is
35    * detected. This implementation may replace the entries in entryArray with its own entry objects
36    * (though they will have the same key/value contents), and will take ownership of entryArray.
37    */
38   static <K, V> ImmutableMap<K, V> create(int n, Entry<K, V>[] entryArray) {
39     Map<K, V> delegateMap = Maps.newHashMapWithExpectedSize(n);
40     for (int i = 0; i < n; i++) {
41       entryArray[i] = makeImmutable(entryArray[i]);
42       V oldValue = delegateMap.putIfAbsent(entryArray[i].getKey(), entryArray[i].getValue());
43       if (oldValue != null) {
44         throw conflictException("key", entryArray[i], entryArray[i].getKey() + "=" + oldValue);
45       }
46     }
47     return new JdkBackedImmutableMap<>(delegateMap, ImmutableList.asImmutableList(entryArray, n));
48   }
49 
50   private final transient Map<K, V> delegateMap;
51   private final transient ImmutableList<Entry<K, V>> entries;
52 
53   JdkBackedImmutableMap(Map<K, V> delegateMap, ImmutableList<Entry<K, V>> entries) {
54     this.delegateMap = delegateMap;
55     this.entries = entries;
56   }
57 
58   @Override
59   public int size() {
60     return entries.size();
61   }
62 
63   @Override
64   public V get(@Nullable Object key) {
65     return delegateMap.get(key);
66   }
67 
68   @Override
69   ImmutableSet<Entry<K, V>> createEntrySet() {
70     return new ImmutableMapEntrySet.RegularEntrySet<K, V>(this, entries);
71   }
72 
73   @Override
74   public void forEach(BiConsumer<? super K, ? super V> action) {
75     checkNotNull(action);
76     entries.forEach(e -> action.accept(e.getKey(), e.getValue()));
77   }
78 
79   @Override
80   ImmutableSet<K> createKeySet() {
81     return new ImmutableMapKeySet<K, V>(this);
82   }
83 
84   @Override
85   ImmutableCollection<V> createValues() {
86     return new ImmutableMapValues<K, V>(this);
87   }
88 
89   @Override
90   boolean isPartialView() {
91     return false;
92   }
93 }