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 17 package com.google.common.collect; 18 19 import static com.google.common.base.Preconditions.checkArgument; 20 21 import com.google.common.annotations.GwtCompatible; 22 import com.google.common.collect.ImmutableMap.IteratorBasedImmutableMap; 23 import java.io.Serializable; 24 import java.util.EnumMap; 25 import java.util.Spliterator; 26 import java.util.function.BiConsumer; 27 import javax.annotation.CheckForNull; 28 29 /** 30 * Implementation of {@link ImmutableMap} backed by a non-empty {@link java.util.EnumMap}. 31 * 32 * @author Louis Wasserman 33 */ 34 @GwtCompatible(serializable = true, emulated = true) 35 @SuppressWarnings("serial") // we're overriding default serialization 36 @ElementTypesAreNonnullByDefault 37 final class ImmutableEnumMap<K extends Enum<K>, V> extends IteratorBasedImmutableMap<K, V> { asImmutable(EnumMap<K, V> map)38 static <K extends Enum<K>, V> ImmutableMap<K, V> asImmutable(EnumMap<K, V> map) { 39 switch (map.size()) { 40 case 0: 41 return ImmutableMap.of(); 42 case 1: 43 Entry<K, V> entry = Iterables.getOnlyElement(map.entrySet()); 44 return ImmutableMap.of(entry.getKey(), entry.getValue()); 45 default: 46 return new ImmutableEnumMap<>(map); 47 } 48 } 49 50 private final transient EnumMap<K, V> delegate; 51 ImmutableEnumMap(EnumMap<K, V> delegate)52 private ImmutableEnumMap(EnumMap<K, V> delegate) { 53 this.delegate = delegate; 54 checkArgument(!delegate.isEmpty()); 55 } 56 57 @Override keyIterator()58 UnmodifiableIterator<K> keyIterator() { 59 return Iterators.unmodifiableIterator(delegate.keySet().iterator()); 60 } 61 62 @Override keySpliterator()63 Spliterator<K> keySpliterator() { 64 return delegate.keySet().spliterator(); 65 } 66 67 @Override size()68 public int size() { 69 return delegate.size(); 70 } 71 72 @Override containsKey(@heckForNull Object key)73 public boolean containsKey(@CheckForNull Object key) { 74 return delegate.containsKey(key); 75 } 76 77 @Override 78 @CheckForNull get(@heckForNull Object key)79 public V get(@CheckForNull Object key) { 80 return delegate.get(key); 81 } 82 83 @Override equals(@heckForNull Object object)84 public boolean equals(@CheckForNull Object object) { 85 if (object == this) { 86 return true; 87 } 88 if (object instanceof ImmutableEnumMap) { 89 object = ((ImmutableEnumMap<?, ?>) object).delegate; 90 } 91 return delegate.equals(object); 92 } 93 94 @Override entryIterator()95 UnmodifiableIterator<Entry<K, V>> entryIterator() { 96 return Maps.unmodifiableEntryIterator(delegate.entrySet().iterator()); 97 } 98 99 @Override entrySpliterator()100 Spliterator<Entry<K, V>> entrySpliterator() { 101 return CollectSpliterators.map(delegate.entrySet().spliterator(), Maps::unmodifiableEntry); 102 } 103 104 @Override forEach(BiConsumer<? super K, ? super V> action)105 public void forEach(BiConsumer<? super K, ? super V> action) { 106 delegate.forEach(action); 107 } 108 109 @Override isPartialView()110 boolean isPartialView() { 111 return false; 112 } 113 114 // All callers of the constructor are restricted to <K extends Enum<K>>. 115 @Override writeReplace()116 Object writeReplace() { 117 return new EnumSerializedForm<>(delegate); 118 } 119 120 /* 121 * This class is used to serialize ImmutableEnumMap instances. 122 */ 123 private static class EnumSerializedForm<K extends Enum<K>, V> implements Serializable { 124 final EnumMap<K, V> delegate; 125 EnumSerializedForm(EnumMap<K, V> delegate)126 EnumSerializedForm(EnumMap<K, V> delegate) { 127 this.delegate = delegate; 128 } 129 readResolve()130 Object readResolve() { 131 return new ImmutableEnumMap<>(delegate); 132 } 133 134 private static final long serialVersionUID = 0; 135 } 136 } 137