| /* |
| * 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 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 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) |
| final class JdkBackedImmutableBiMap<K, V> extends ImmutableBiMap<K, V> { |
| @VisibleForTesting |
| static <K, V> ImmutableBiMap<K, V> create(int n, 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++) { |
| Entry<K, V> e = RegularImmutableMap.makeImmutable(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 private transient JdkBackedImmutableBiMap<V, K> inverse; |
| |
| @Override |
| public ImmutableBiMap<V, K> inverse() { |
| JdkBackedImmutableBiMap<V, K> result = inverse; |
| if (result == null) { |
| inverse = |
| result = |
| new JdkBackedImmutableBiMap<V, K>( |
| 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 |
| public V get(@Nullable Object key) { |
| return forwardDelegate.get(key); |
| } |
| |
| @Override |
| ImmutableSet<Entry<K, V>> createEntrySet() { |
| return new ImmutableMapEntrySet.RegularEntrySet<K, V>(this, entries); |
| } |
| |
| @Override |
| ImmutableSet<K> createKeySet() { |
| return new ImmutableMapKeySet<K, V>(this); |
| } |
| |
| @Override |
| boolean isPartialView() { |
| return false; |
| } |
| } |