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.collect.CollectPreconditions.checkEntryNotNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.ImmutableMapEntry.TerminalEntry;
import java.io.Serializable;
import javax.annotation.Nullable;
/**
* Bimap with two or more mappings.
*
* @author Louis Wasserman
*/
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
class RegularImmutableBiMap extends ImmutableBiMap {
static final double MAX_LOAD_FACTOR = 1.2;
private final transient ImmutableMapEntry[] keyTable;
private final transient ImmutableMapEntry[] valueTable;
private final transient ImmutableMapEntry[] entries;
private final transient int mask;
private final transient int hashCode;
RegularImmutableBiMap(TerminalEntry... entriesToAdd) {
this(entriesToAdd.length, entriesToAdd);
}
/**
* Constructor for RegularImmutableBiMap that takes as input an array of {@code TerminalEntry}
* entries. Assumes that these entries have already been checked for null.
*
* This allows reuse of the entry objects from the array in the actual implementation.
*/
RegularImmutableBiMap(int n, TerminalEntry[] entriesToAdd) {
int tableSize = Hashing.closedTableSize(n, MAX_LOAD_FACTOR);
this.mask = tableSize - 1;
ImmutableMapEntry[] keyTable = createEntryArray(tableSize);
ImmutableMapEntry[] valueTable = createEntryArray(tableSize);
ImmutableMapEntry[] entries = createEntryArray(n);
int hashCode = 0;
for (int i = 0; i < n; i++) {
@SuppressWarnings("unchecked")
TerminalEntry entry = (TerminalEntry) entriesToAdd[i];
K key = entry.getKey();
V value = entry.getValue();
int keyHash = key.hashCode();
int valueHash = value.hashCode();
int keyBucket = Hashing.smear(keyHash) & mask;
int valueBucket = Hashing.smear(valueHash) & mask;
ImmutableMapEntry nextInKeyBucket = keyTable[keyBucket];
for (ImmutableMapEntry keyEntry = nextInKeyBucket; keyEntry != null;
keyEntry = keyEntry.getNextInKeyBucket()) {
checkNoConflict(!key.equals(keyEntry.getKey()), "key", entry, keyEntry);
}
ImmutableMapEntry nextInValueBucket = valueTable[valueBucket];
for (ImmutableMapEntry valueEntry = nextInValueBucket; valueEntry != null;
valueEntry = valueEntry.getNextInValueBucket()) {
checkNoConflict(!value.equals(valueEntry.getValue()), "value", entry, valueEntry);
}
ImmutableMapEntry newEntry =
(nextInKeyBucket == null && nextInValueBucket == null)
? entry
: new NonTerminalBiMapEntry(entry, nextInKeyBucket, nextInValueBucket);
keyTable[keyBucket] = newEntry;
valueTable[valueBucket] = newEntry;
entries[i] = newEntry;
hashCode += keyHash ^ valueHash;
}
this.keyTable = keyTable;
this.valueTable = valueTable;
this.entries = entries;
this.hashCode = hashCode;
}
/**
* Constructor for RegularImmutableBiMap that makes no assumptions about the input entries.
*/
RegularImmutableBiMap(Entry[] entriesToAdd) {
int n = entriesToAdd.length;
int tableSize = Hashing.closedTableSize(n, MAX_LOAD_FACTOR);
this.mask = tableSize - 1;
ImmutableMapEntry[] keyTable = createEntryArray(tableSize);
ImmutableMapEntry[] valueTable = createEntryArray(tableSize);
ImmutableMapEntry[] entries = createEntryArray(n);
int hashCode = 0;
for (int i = 0; i < n; i++) {
@SuppressWarnings("unchecked")
Entry entry = (Entry) entriesToAdd[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];
for (ImmutableMapEntry keyEntry = nextInKeyBucket; keyEntry != null;
keyEntry = keyEntry.getNextInKeyBucket()) {
checkNoConflict(!key.equals(keyEntry.getKey()), "key", entry, keyEntry);
}
ImmutableMapEntry nextInValueBucket = valueTable[valueBucket];
for (ImmutableMapEntry valueEntry = nextInValueBucket; valueEntry != null;
valueEntry = valueEntry.getNextInValueBucket()) {
checkNoConflict(!value.equals(valueEntry.getValue()), "value", entry, valueEntry);
}
ImmutableMapEntry newEntry =
(nextInKeyBucket == null && nextInValueBucket == null)
? new TerminalEntry(key, value)
: new NonTerminalBiMapEntry(key, value, nextInKeyBucket, nextInValueBucket);
keyTable[keyBucket] = newEntry;
valueTable[valueBucket] = newEntry;
entries[i] = newEntry;
hashCode += keyHash ^ valueHash;
}
this.keyTable = keyTable;
this.valueTable = valueTable;
this.entries = entries;
this.hashCode = hashCode;
}
private static final class NonTerminalBiMapEntry extends ImmutableMapEntry {
@Nullable private final ImmutableMapEntry nextInKeyBucket;
@Nullable private final ImmutableMapEntry nextInValueBucket;
NonTerminalBiMapEntry(K key, V value, @Nullable ImmutableMapEntry nextInKeyBucket,
@Nullable ImmutableMapEntry nextInValueBucket) {
super(key, value);
this.nextInKeyBucket = nextInKeyBucket;
this.nextInValueBucket = nextInValueBucket;
}
NonTerminalBiMapEntry(ImmutableMapEntry contents,
@Nullable ImmutableMapEntry nextInKeyBucket,
@Nullable ImmutableMapEntry nextInValueBucket) {
super(contents);
this.nextInKeyBucket = nextInKeyBucket;
this.nextInValueBucket = nextInValueBucket;
}
@Override
@Nullable
ImmutableMapEntry getNextInKeyBucket() {
return nextInKeyBucket;
}
@Override
@Nullable
ImmutableMapEntry getNextInValueBucket() {
return nextInValueBucket;
}
}
@SuppressWarnings("unchecked")
private static ImmutableMapEntry[] createEntryArray(int length) {
return new ImmutableMapEntry[length];
}
@Override
@Nullable
public V get(@Nullable Object key) {
if (key == null) {
return null;
}
int bucket = Hashing.smear(key.hashCode()) & mask;
for (ImmutableMapEntry entry = keyTable[bucket]; entry != null;
entry = entry.getNextInKeyBucket()) {
if (key.equals(entry.getKey())) {
return entry.getValue();
}
}
return null;
}
@Override
ImmutableSet> createEntrySet() {
return new ImmutableMapEntrySet() {
@Override
ImmutableMap map() {
return RegularImmutableBiMap.this;
}
@Override
public UnmodifiableIterator> iterator() {
return asList().iterator();
}
@Override
ImmutableList> createAsList() {
return new RegularImmutableAsList>(this, entries);
}
@Override
boolean isHashCodeFast() {
return true;
}
@Override
public int hashCode() {
return hashCode;
}
};
}
@Override
boolean isPartialView() {
return false;
}
@Override
public int size() {
return entries.length;
}
private transient ImmutableBiMap inverse;
@Override
public ImmutableBiMap inverse() {
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 K get(@Nullable Object value) {
if (value == 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> 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
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;
}
};
}
}
@Override
boolean isPartialView() {
return false;
}
@Override
Object writeReplace() {
return new InverseSerializedForm(RegularImmutableBiMap.this);
}
}
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;
}
}