com.google.common.collect.RegularImmutableBiMap Maven / Gradle / Ivy
/*
* Copyright (C) 2008 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 com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkPositionIndex;
import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
import static com.google.common.collect.ImmutableMapEntry.createEntryArray;
import static com.google.common.collect.RegularImmutableMap.MAX_HASH_BUCKET_LENGTH;
import static com.google.common.collect.RegularImmutableMap.checkNoConflictInKeyBucket;
import static java.util.Objects.requireNonNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableMapEntry.NonTerminalImmutableBiMapEntry;
import com.google.common.collect.RegularImmutableMap.BucketOverflowException;
import com.google.errorprone.annotations.concurrent.LazyInit;
import com.google.j2objc.annotations.RetainedWith;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Bimap with zero or more mappings.
*
* @author Louis Wasserman
*/
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
@ElementTypesAreNonnullByDefault
class RegularImmutableBiMap extends ImmutableBiMap {
@SuppressWarnings("unchecked") // TODO(cpovirk): Consider storing Entry[] instead.
static final RegularImmutableBiMap EMPTY =
new RegularImmutableBiMap<>(
null, null, (Entry[]) ImmutableMap.EMPTY_ENTRY_ARRAY, 0, 0);
static final double MAX_LOAD_FACTOR = 1.2;
@CheckForNull private final transient @Nullable ImmutableMapEntry[] keyTable;
@CheckForNull private final transient @Nullable ImmutableMapEntry[] valueTable;
@VisibleForTesting final transient Entry[] entries;
private final transient int mask;
private final transient int hashCode;
static ImmutableBiMap fromEntries(Entry... entries) {
return fromEntryArray(entries.length, entries);
}
static ImmutableBiMap fromEntryArray(int n, @Nullable Entry[] entryArray) {
checkPositionIndex(n, entryArray.length);
int tableSize = Hashing.closedTableSize(n, MAX_LOAD_FACTOR);
int mask = tableSize - 1;
@Nullable ImmutableMapEntry[] keyTable = createEntryArray(tableSize);
@Nullable ImmutableMapEntry[] valueTable = createEntryArray(tableSize);
/*
* The cast is safe: n==entryArray.length means that we have filled the whole array with Entry
* instances, in which case it is safe to cast it from an array of nullable entries to an array
* of non-null entries.
*/
@SuppressWarnings("nullness")
Entry[] entries =
(n == entryArray.length) ? (Entry[]) entryArray : createEntryArray(n);
int hashCode = 0;
for (int i = 0; i < n; i++) {
// requireNonNull is safe because the first `n` elements have been filled in.
Entry entry = requireNonNull(entryArray[i]);
K key = entry.getKey();
V value = entry.getValue();
checkEntryNotNull(key, value);
int keyHash = key.hashCode();
int valueHash = value.hashCode();
int keyBucket = Hashing.smear(keyHash) & mask;
int valueBucket = Hashing.smear(valueHash) & mask;
ImmutableMapEntry nextInKeyBucket = keyTable[keyBucket];
ImmutableMapEntry nextInValueBucket = valueTable[valueBucket];
try {
checkNoConflictInKeyBucket(key, value, nextInKeyBucket, /* throwIfDuplicateKeys= */ true);
checkNoConflictInValueBucket(value, entry, nextInValueBucket);
} catch (BucketOverflowException e) {
return JdkBackedImmutableBiMap.create(n, entryArray);
}
ImmutableMapEntry newEntry =
(nextInValueBucket == null && nextInKeyBucket == null)
? RegularImmutableMap.makeImmutable(entry, key, value)
: new NonTerminalImmutableBiMapEntry<>(
key, value, nextInKeyBucket, nextInValueBucket);
keyTable[keyBucket] = newEntry;
valueTable[valueBucket] = newEntry;
entries[i] = newEntry;
hashCode += keyHash ^ valueHash;
}
return new RegularImmutableBiMap<>(keyTable, valueTable, entries, mask, hashCode);
}
private RegularImmutableBiMap(
@CheckForNull @Nullable ImmutableMapEntry[] keyTable,
@CheckForNull @Nullable ImmutableMapEntry[] valueTable,
Entry[] entries,
int mask,
int hashCode) {
this.keyTable = keyTable;
this.valueTable = valueTable;
this.entries = entries;
this.mask = mask;
this.hashCode = hashCode;
}
// checkNoConflictInKeyBucket is static imported from RegularImmutableMap
/**
* @throws IllegalArgumentException if another entry in the bucket has the same key
* @throws BucketOverflowException if this bucket has too many entries, which may indicate a hash
* flooding attack
*/
private static void checkNoConflictInValueBucket(
Object value, Entry entry, @CheckForNull ImmutableMapEntry valueBucketHead)
throws BucketOverflowException {
int bucketSize = 0;
for (; valueBucketHead != null; valueBucketHead = valueBucketHead.getNextInValueBucket()) {
checkNoConflict(!value.equals(valueBucketHead.getValue()), "value", entry, valueBucketHead);
if (++bucketSize > MAX_HASH_BUCKET_LENGTH) {
throw new BucketOverflowException();
}
}
}
@Override
@CheckForNull
public V get(@CheckForNull Object key) {
return RegularImmutableMap.get(key, keyTable, mask);
}
@Override
ImmutableSet> createEntrySet() {
return isEmpty()
? ImmutableSet.>of()
: new ImmutableMapEntrySet.RegularEntrySet(this, entries);
}
@Override
ImmutableSet createKeySet() {
return new ImmutableMapKeySet<>(this);
}
@Override
public void forEach(BiConsumer action) {
checkNotNull(action);
for (Entry entry : entries) {
action.accept(entry.getKey(), entry.getValue());
}
}
@Override
boolean isHashCodeFast() {
return true;
}
@Override
public int hashCode() {
return hashCode;
}
@Override
boolean isPartialView() {
return false;
}
@Override
public int size() {
return entries.length;
}
@LazyInit @RetainedWith @CheckForNull private transient ImmutableBiMap inverse;
@Override
public ImmutableBiMap inverse() {
if (isEmpty()) {
return ImmutableBiMap.of();
}
ImmutableBiMap result = inverse;
return (result == null) ? inverse = new Inverse() : result;
}
private final class Inverse extends ImmutableBiMap {
@Override
public int size() {
return inverse().size();
}
@Override
public ImmutableBiMap inverse() {
return RegularImmutableBiMap.this;
}
@Override
public void forEach(BiConsumer action) {
checkNotNull(action);
RegularImmutableBiMap.this.forEach((k, v) -> action.accept(v, k));
}
@Override
@CheckForNull
public K get(@CheckForNull Object value) {
if (value == null || valueTable == null) {
return null;
}
int bucket = Hashing.smear(value.hashCode()) & mask;
for (ImmutableMapEntry entry = valueTable[bucket];
entry != null;
entry = entry.getNextInValueBucket()) {
if (value.equals(entry.getValue())) {
return entry.getKey();
}
}
return null;
}
@Override
ImmutableSet createKeySet() {
return new ImmutableMapKeySet<>(this);
}
@Override
ImmutableSet> createEntrySet() {
return new InverseEntrySet();
}
final class InverseEntrySet extends ImmutableMapEntrySet {
@Override
ImmutableMap map() {
return Inverse.this;
}
@Override
boolean isHashCodeFast() {
return true;
}
@Override
public int hashCode() {
return hashCode;
}
@Override
public UnmodifiableIterator> iterator() {
return asList().iterator();
}
@Override
public void forEach(Consumer> action) {
asList().forEach(action);
}
@Override
ImmutableList> createAsList() {
return new ImmutableAsList>() {
@Override
public Entry get(int index) {
Entry entry = entries[index];
return Maps.immutableEntry(entry.getValue(), entry.getKey());
}
@Override
ImmutableCollection> delegateCollection() {
return InverseEntrySet.this;
}
// redeclare to help optimizers with b/310253115
@SuppressWarnings("RedundantOverride")
@Override
@J2ktIncompatible // serialization
@GwtIncompatible // serialization
Object writeReplace() {
return super.writeReplace();
}
};
}
// redeclare to help optimizers with b/310253115
@SuppressWarnings("RedundantOverride")
@Override
@J2ktIncompatible // serialization
@GwtIncompatible // serialization
Object writeReplace() {
return super.writeReplace();
}
}
@Override
boolean isPartialView() {
return false;
}
@Override
@J2ktIncompatible // serialization
@GwtIncompatible // serialization
Object writeReplace() {
return new InverseSerializedForm<>(RegularImmutableBiMap.this);
}
@J2ktIncompatible // java.io.ObjectInputStream
private void readObject(ObjectInputStream stream) throws InvalidObjectException {
throw new InvalidObjectException("Use InverseSerializedForm");
}
}
@J2ktIncompatible // serialization
private static class InverseSerializedForm implements Serializable {
private final ImmutableBiMap forward;
InverseSerializedForm(ImmutableBiMap forward) {
this.forward = forward;
}
Object readResolve() {
return forward.inverse();
}
private static final long serialVersionUID = 1;
}
// redeclare to help optimizers with b/310253115
@SuppressWarnings("RedundantOverride")
@Override
@J2ktIncompatible // serialization
@GwtIncompatible // serialization
Object writeReplace() {
return super.writeReplace();
}
}
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