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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 java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Internal representation of map fields in generated messages.
*
* This class supports accessing the map field as a {@link Map} to be used in generated API and
* also supports accessing the field as a {@link List} to be used in reflection API. It keeps track
* of where the data is currently stored and do necessary conversions between map and list.
*
*
This class is a protobuf implementation detail. Users shouldn't use this class directly.
*
*
THREAD-SAFETY NOTE: Read-only access is thread-safe. Users can call getMap() and getList()
* concurrently in multiple threads. If write-access is needed, all access must be synchronized.
*/
public class MapField extends MapFieldReflectionAccessor implements MutabilityOracle {
/**
* Indicates where the data of this map field is currently stored.
*
*
* - MAP: Data is stored in mapData.
*
- LIST: Data is stored in listData.
*
- BOTH: mapData and listData have the same data.
*
*
* When the map field is accessed (through generated API or reflection API), it will shift
* between these 3 modes:
*
*
* getMap() getList() getMutableMap() getMutableList()
* MAP MAP BOTH MAP LIST
* LIST BOTH LIST MAP LIST
* BOTH BOTH BOTH MAP LIST
*
*
* As the map field changes its mode, the list/map reference returned in a previous method call
* may be invalidated.
*/
private enum StorageMode {
MAP,
LIST,
BOTH
}
private volatile boolean isMutable;
private volatile StorageMode mode;
private MutabilityAwareMap mapData;
private List listData;
// Convert between a map entry Message and a key-value pair.
private static interface Converter {
Message convertKeyAndValueToMessage(K key, V value);
void convertMessageToKeyAndValue(Message message, Map map);
Message getMessageDefaultInstance();
}
private static class ImmutableMessageConverter implements Converter {
private final MapEntry defaultEntry;
public ImmutableMessageConverter(MapEntry defaultEntry) {
this.defaultEntry = defaultEntry;
}
@Override
public Message convertKeyAndValueToMessage(K key, V value) {
return defaultEntry.newBuilderForType().setKey(key).setValue(value).buildPartial();
}
@Override
@SuppressWarnings("unchecked")
public void convertMessageToKeyAndValue(Message message, Map map) {
MapEntry entry = (MapEntry) message;
map.put(entry.getKey(), entry.getValue());
}
@Override
public Message getMessageDefaultInstance() {
return defaultEntry;
}
}
private final Converter converter;
private MapField(Converter converter, StorageMode mode, Map mapData) {
this.converter = converter;
this.isMutable = true;
this.mode = mode;
this.mapData = new MutabilityAwareMap(this, mapData);
this.listData = null;
}
private MapField(MapEntry defaultEntry, StorageMode mode, Map mapData) {
this(new ImmutableMessageConverter(defaultEntry), mode, mapData);
}
/** Returns an immutable empty MapField. */
public static MapField emptyMapField(MapEntry defaultEntry) {
return new MapField(defaultEntry, StorageMode.MAP, Collections.emptyMap());
}
/** Creates a new mutable empty MapField. */
public static MapField newMapField(MapEntry defaultEntry) {
return new MapField(defaultEntry, StorageMode.MAP, new LinkedHashMap());
}
private Message convertKeyAndValueToMessage(K key, V value) {
return converter.convertKeyAndValueToMessage(key, value);
}
private void convertMessageToKeyAndValue(Message message, Map map) {
converter.convertMessageToKeyAndValue(message, map);
}
private List convertMapToList(MutabilityAwareMap mapData) {
List listData = new ArrayList();
for (Map.Entry entry : mapData.entrySet()) {
listData.add(convertKeyAndValueToMessage(entry.getKey(), entry.getValue()));
}
return listData;
}
private MutabilityAwareMap convertListToMap(List listData) {
Map mapData = new LinkedHashMap();
for (Message item : listData) {
convertMessageToKeyAndValue(item, mapData);
}
return new MutabilityAwareMap(this, mapData);
}
/** Returns the content of this MapField as a read-only Map. */
public Map getMap() {
if (mode == StorageMode.LIST) {
synchronized (this) {
if (mode == StorageMode.LIST) {
mapData = convertListToMap(listData);
mode = StorageMode.BOTH;
}
}
}
return Collections.unmodifiableMap(mapData);
}
/** Gets a mutable Map view of this MapField. */
public Map getMutableMap() {
if (mode != StorageMode.MAP) {
if (mode == StorageMode.LIST) {
mapData = convertListToMap(listData);
}
listData = null;
mode = StorageMode.MAP;
}
return mapData;
}
public void mergeFrom(MapField other) {
getMutableMap().putAll(MapFieldLite.copy(other.getMap()));
}
public void clear() {
mapData = new MutabilityAwareMap(this, new LinkedHashMap());
mode = StorageMode.MAP;
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object object) {
if (!(object instanceof MapField)) {
return false;
}
MapField other = (MapField) object;
return MapFieldLite.equals(getMap(), other.getMap());
}
@Override
public int hashCode() {
return MapFieldLite.calculateHashCodeForMap(getMap());
}
/** Returns a deep copy of this MapField. */
public MapField copy() {
return new MapField(converter, StorageMode.MAP, MapFieldLite.copy(getMap()));
}
/** Gets the content of this MapField as a read-only List. */
@Override
List getList() {
if (mode == StorageMode.MAP) {
synchronized (this) {
if (mode == StorageMode.MAP) {
listData = convertMapToList(mapData);
mode = StorageMode.BOTH;
}
}
}
return Collections.unmodifiableList(listData);
}
/** Gets a mutable List view of this MapField. */
@Override
List getMutableList() {
if (mode != StorageMode.LIST) {
if (mode == StorageMode.MAP) {
listData = convertMapToList(mapData);
}
mapData = null;
mode = StorageMode.LIST;
}
return listData;
}
/** Gets the default instance of the message stored in the list view of this map field. */
@Override
Message getMapEntryMessageDefaultInstance() {
return converter.getMessageDefaultInstance();
}
/**
* Makes this list 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;
}
/* (non-Javadoc)
* @see com.google.protobuf.MutabilityOracle#ensureMutable()
*/
@Override
public void ensureMutable() {
if (!isMutable()) {
throw new UnsupportedOperationException();
}
}
/** An internal map that checks for mutability before delegating. */
static class MutabilityAwareMap implements Map {
private final MutabilityOracle mutabilityOracle;
private final Map delegate;
MutabilityAwareMap(MutabilityOracle mutabilityOracle, Map delegate) {
this.mutabilityOracle = mutabilityOracle;
this.delegate = delegate;
}
@Override
public int size() {
return delegate.size();
}
@Override
public boolean isEmpty() {
return delegate.isEmpty();
}
@Override
public boolean containsKey(Object key) {
return delegate.containsKey(key);
}
@Override
public boolean containsValue(Object value) {
return delegate.containsValue(value);
}
@Override
public V get(Object key) {
return delegate.get(key);
}
@Override
public V put(K key, V value) {
mutabilityOracle.ensureMutable();
checkNotNull(key);
checkNotNull(value);
return delegate.put(key, value);
}
@Override
public V remove(Object key) {
mutabilityOracle.ensureMutable();
return delegate.remove(key);
}
@Override
public void putAll(Map m) {
mutabilityOracle.ensureMutable();
for (K key : m.keySet()) {
checkNotNull(key);
checkNotNull(m.get(key));
}
delegate.putAll(m);
}
@Override
public void clear() {
mutabilityOracle.ensureMutable();
delegate.clear();
}
@Override
public Set keySet() {
return new MutabilityAwareSet(mutabilityOracle, delegate.keySet());
}
@Override
public Collection values() {
return new MutabilityAwareCollection(mutabilityOracle, delegate.values());
}
@Override
public Set> entrySet() {
return new MutabilityAwareSet>(mutabilityOracle, delegate.entrySet());
}
@Override
public boolean equals(Object o) {
return delegate.equals(o);
}
@Override
public int hashCode() {
return delegate.hashCode();
}
@Override
public String toString() {
return delegate.toString();
}
/** An internal collection that checks for mutability before delegating. */
private static class MutabilityAwareCollection implements Collection {
private final MutabilityOracle mutabilityOracle;
private final Collection delegate;
MutabilityAwareCollection(MutabilityOracle mutabilityOracle, Collection delegate) {
this.mutabilityOracle = mutabilityOracle;
this.delegate = delegate;
}
@Override
public int size() {
return delegate.size();
}
@Override
public boolean isEmpty() {
return delegate.isEmpty();
}
@Override
public boolean contains(Object o) {
return delegate.contains(o);
}
@Override
public Iterator iterator() {
return new MutabilityAwareIterator(mutabilityOracle, delegate.iterator());
}
@Override
public Object[] toArray() {
return delegate.toArray();
}
@Override
public T[] toArray(T[] a) {
return delegate.toArray(a);
}
@Override
public boolean add(E e) {
// Unsupported operation in the delegate.
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
mutabilityOracle.ensureMutable();
return delegate.remove(o);
}
@Override
public boolean containsAll(Collection c) {
return delegate.containsAll(c);
}
@Override
public boolean addAll(Collection c) {
// Unsupported operation in the delegate.
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection c) {
mutabilityOracle.ensureMutable();
return delegate.removeAll(c);
}
@Override
public boolean retainAll(Collection c) {
mutabilityOracle.ensureMutable();
return delegate.retainAll(c);
}
@Override
public void clear() {
mutabilityOracle.ensureMutable();
delegate.clear();
}
@Override
public boolean equals(Object o) {
return delegate.equals(o);
}
@Override
public int hashCode() {
return delegate.hashCode();
}
@Override
public String toString() {
return delegate.toString();
}
}
/** An internal set that checks for mutability before delegating. */
private static class MutabilityAwareSet implements Set {
private final MutabilityOracle mutabilityOracle;
private final Set delegate;
MutabilityAwareSet(MutabilityOracle mutabilityOracle, Set delegate) {
this.mutabilityOracle = mutabilityOracle;
this.delegate = delegate;
}
@Override
public int size() {
return delegate.size();
}
@Override
public boolean isEmpty() {
return delegate.isEmpty();
}
@Override
public boolean contains(Object o) {
return delegate.contains(o);
}
@Override
public Iterator iterator() {
return new MutabilityAwareIterator(mutabilityOracle, delegate.iterator());
}
@Override
public Object[] toArray() {
return delegate.toArray();
}
@Override
public T[] toArray(T[] a) {
return delegate.toArray(a);
}
@Override
public boolean add(E e) {
mutabilityOracle.ensureMutable();
return delegate.add(e);
}
@Override
public boolean remove(Object o) {
mutabilityOracle.ensureMutable();
return delegate.remove(o);
}
@Override
public boolean containsAll(Collection c) {
return delegate.containsAll(c);
}
@Override
public boolean addAll(Collection c) {
mutabilityOracle.ensureMutable();
return delegate.addAll(c);
}
@Override
public boolean retainAll(Collection c) {
mutabilityOracle.ensureMutable();
return delegate.retainAll(c);
}
@Override
public boolean removeAll(Collection c) {
mutabilityOracle.ensureMutable();
return delegate.removeAll(c);
}
@Override
public void clear() {
mutabilityOracle.ensureMutable();
delegate.clear();
}
@Override
public boolean equals(Object o) {
return delegate.equals(o);
}
@Override
public int hashCode() {
return delegate.hashCode();
}
@Override
public String toString() {
return delegate.toString();
}
}
/** An internal iterator that checks for mutability before delegating. */
private static class MutabilityAwareIterator implements Iterator {
private final MutabilityOracle mutabilityOracle;
private final Iterator delegate;
MutabilityAwareIterator(MutabilityOracle mutabilityOracle, Iterator delegate) {
this.mutabilityOracle = mutabilityOracle;
this.delegate = delegate;
}
@Override
public boolean hasNext() {
return delegate.hasNext();
}
@Override
public E next() {
return delegate.next();
}
@Override
public void remove() {
mutabilityOracle.ensureMutable();
delegate.remove();
}
@Override
public boolean equals(Object obj) {
return delegate.equals(obj);
}
@Override
public int hashCode() {
return delegate.hashCode();
}
@Override
public String toString() {
return delegate.toString();
}
}
}
}