com.google.protobuf.MapFieldLite Maven / Gradle / Ivy
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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
package com.google.protobuf;
import static com.google.protobuf.Internal.checkNotNull;
import com.google.protobuf.Internal.EnumLite;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
/**
* Internal representation of map fields in generated lite-runtime messages.
*
* This class is a protobuf implementation detail. Users shouldn't use this class directly.
*/
public final class MapFieldLite extends LinkedHashMap {
private boolean isMutable;
private MapFieldLite() {
this.isMutable = true;
}
private MapFieldLite(Map mapData) {
super(mapData);
this.isMutable = true;
}
private static final MapFieldLite EMPTY_MAP_FIELD = new MapFieldLite<>();
static {
EMPTY_MAP_FIELD.makeImmutable();
}
/** Returns a singleton immutable empty MapFieldLite instance. */
@SuppressWarnings("unchecked")
public static MapFieldLite emptyMapField() {
return (MapFieldLite) EMPTY_MAP_FIELD;
}
public void mergeFrom(MapFieldLite other) {
ensureMutable();
if (!other.isEmpty()) {
putAll(other);
}
}
@Override
public Set> entrySet() {
return isEmpty() ? Collections.>emptySet() : super.entrySet();
}
@Override
public void clear() {
ensureMutable();
super.clear();
}
@Override
public V put(K key, V value) {
ensureMutable();
checkNotNull(key);
checkNotNull(value);
return super.put(key, value);
}
public V put(Map.Entry entry) {
return put(entry.getKey(), entry.getValue());
}
@Override
public void putAll(Map m) {
ensureMutable();
checkForNullKeysAndValues(m);
super.putAll(m);
}
@Override
public V remove(Object key) {
ensureMutable();
return super.remove(key);
}
private static void checkForNullKeysAndValues(Map m) {
for (Object key : m.keySet()) {
checkNotNull(key);
checkNotNull(m.get(key));
}
}
private static boolean equals(Object a, Object b) {
if (a instanceof byte[] && b instanceof byte[]) {
return Arrays.equals((byte[]) a, (byte[]) b);
}
return a.equals(b);
}
/**
* Checks whether two {@link Map}s are equal. We don't use the default equals method of {@link
* Map} because it compares by identity not by content for byte arrays.
*/
static boolean equals(Map a, Map b) {
if (a == b) {
return true;
}
if (a.size() != b.size()) {
return false;
}
for (Map.Entry entry : a.entrySet()) {
if (!b.containsKey(entry.getKey())) {
return false;
}
if (!equals(entry.getValue(), b.get(entry.getKey()))) {
return false;
}
}
return true;
}
/** Checks whether two map fields are equal. */
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object object) {
return (object instanceof Map) && equals(this, (Map) object);
}
private static int calculateHashCodeForObject(Object a) {
if (a instanceof byte[]) {
return Internal.hashCode((byte[]) a);
}
// Enums should be stored as integers internally.
if (a instanceof EnumLite) {
throw new UnsupportedOperationException();
}
return a.hashCode();
}
/**
* Calculates the hash code for a {@link Map}. We don't use the default hash code method of {@link
* Map} because for byte arrays and protobuf enums it use {@link Object#hashCode()}.
*/
static int calculateHashCodeForMap(Map a) {
int result = 0;
for (Map.Entry entry : a.entrySet()) {
result +=
calculateHashCodeForObject(entry.getKey()) ^ calculateHashCodeForObject(entry.getValue());
}
return result;
}
@Override
public int hashCode() {
return calculateHashCodeForMap(this);
}
private static Object copy(Object object) {
if (object instanceof byte[]) {
byte[] data = (byte[]) object;
return Arrays.copyOf(data, data.length);
}
return object;
}
/**
* Makes a deep copy of a {@link Map}. Immutable objects in the map will be shared (e.g.,
* integers, strings, immutable messages) and mutable ones will have a copy (e.g., byte arrays,
* mutable messages).
*/
@SuppressWarnings("unchecked")
static Map copy(Map map) {
Map result = new LinkedHashMap(map.size() * 4 / 3 + 1);
for (Map.Entry entry : map.entrySet()) {
result.put(entry.getKey(), (V) copy(entry.getValue()));
}
return result;
}
/** Returns a deep copy of this map field. */
public MapFieldLite mutableCopy() {
return isEmpty() ? new MapFieldLite() : new MapFieldLite(this);
}
/**
* Makes this field immutable. All subsequent modifications will throw an {@link
* UnsupportedOperationException}.
*/
public void makeImmutable() {
isMutable = false;
}
/** Returns whether this field can be modified. */
public boolean isMutable() {
return isMutable;
}
private void ensureMutable() {
if (!isMutable()) {
throw new UnsupportedOperationException();
}
}
}