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/*
* Copyright (C) 2018 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import static java.util.Objects.requireNonNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.errorprone.annotations.concurrent.LazyInit;
import com.google.j2objc.annotations.RetainedWith;
import com.google.j2objc.annotations.WeakOuter;
import java.util.Map;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Implementation of ImmutableBiMap backed by a pair of JDK HashMaps, which have smartness
* protecting against hash flooding.
*/
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class JdkBackedImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
@VisibleForTesting
static <K, V> ImmutableBiMap<K, V> create(int n, @Nullable Entry<K, V>[] entryArray) {
Map<K, V> forwardDelegate = Maps.newHashMapWithExpectedSize(n);
Map<V, K> backwardDelegate = Maps.newHashMapWithExpectedSize(n);
for (int i = 0; i < n; i++) {
// requireNonNull is safe because the first `n` elements have been filled in.
Entry<K, V> e = RegularImmutableMap.makeImmutable(requireNonNull(entryArray[i]));
entryArray[i] = e;
V oldValue = forwardDelegate.putIfAbsent(e.getKey(), e.getValue());
if (oldValue != null) {
throw conflictException("key", e.getKey() + "=" + oldValue, entryArray[i]);
}
K oldKey = backwardDelegate.putIfAbsent(e.getValue(), e.getKey());
if (oldKey != null) {
throw conflictException("value", oldKey + "=" + e.getValue(), entryArray[i]);
}
}
ImmutableList<Entry<K, V>> entryList = ImmutableList.asImmutableList(entryArray, n);
return new JdkBackedImmutableBiMap<>(entryList, forwardDelegate, backwardDelegate);
}
private final transient ImmutableList<Entry<K, V>> entries;
private final Map<K, V> forwardDelegate;
private final Map<V, K> backwardDelegate;
private JdkBackedImmutableBiMap(
ImmutableList<Entry<K, V>> entries, Map<K, V> forwardDelegate, Map<V, K> backwardDelegate) {
this.entries = entries;
this.forwardDelegate = forwardDelegate;
this.backwardDelegate = backwardDelegate;
}
@Override
public int size() {
return entries.size();
}
@LazyInit @RetainedWith @CheckForNull private transient JdkBackedImmutableBiMap<V, K> inverse;
@Override
public ImmutableBiMap<V, K> inverse() {
JdkBackedImmutableBiMap<V, K> result = inverse;
if (result == null) {
inverse =
result =
new JdkBackedImmutableBiMap<>(
new InverseEntries(), backwardDelegate, forwardDelegate);
result.inverse = this;
}
return result;
}
@WeakOuter
private final class InverseEntries extends ImmutableList<Entry<V, K>> {
@Override
public Entry<V, K> get(int index) {
Entry<K, V> entry = entries.get(index);
return Maps.immutableEntry(entry.getValue(), entry.getKey());
}
@Override
boolean isPartialView() {
return false;
}
@Override
public int size() {
return entries.size();
}
}
@Override
@CheckForNull
public V get(@CheckForNull Object key) {
return forwardDelegate.get(key);
}
@Override
ImmutableSet<Entry<K, V>> createEntrySet() {
return new ImmutableMapEntrySet.RegularEntrySet<>(this, entries);
}
@Override
ImmutableSet<K> createKeySet() {
return new ImmutableMapKeySet<>(this);
}
@Override
boolean isPartialView() {
return false;
}
}
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