org.apache.flink.runtime.state.HashMapSerializer Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.flink.runtime.state;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.typeutils.CompatibilityResult;
import org.apache.flink.api.common.typeutils.CompatibilityUtil;
import org.apache.flink.api.common.typeutils.TypeDeserializerAdapter;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.TypeSerializerConfigSnapshot;
import org.apache.flink.api.common.typeutils.UnloadableDummyTypeSerializer;
import org.apache.flink.api.common.typeutils.base.MapSerializerConfigSnapshot;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.util.Preconditions;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* A serializer for {@link HashMap}. The serializer relies on a key serializer and a value serializer
* for the serialization of the map's key-value pairs.
*
* The serialization format for the map is as follows: four bytes for the length of the map,
* followed by the serialized representation of each key-value pair. To allow null values, each value
* is prefixed by a null marker.
*
* @param The type of the keys in the map.
* @param The type of the values in the map.
*/
@Internal
public final class HashMapSerializer extends TypeSerializer> {
private static final long serialVersionUID = -6885593032367050078L;
/** The serializer for the keys in the map */
private final TypeSerializer keySerializer;
/** The serializer for the values in the map */
private final TypeSerializer valueSerializer;
/**
* Creates a map serializer that uses the given serializers to serialize the key-value pairs in the map.
*
* @param keySerializer The serializer for the keys in the map
* @param valueSerializer The serializer for the values in the map
*/
public HashMapSerializer(TypeSerializer keySerializer, TypeSerializer valueSerializer) {
this.keySerializer = Preconditions.checkNotNull(keySerializer, "The key serializer cannot be null");
this.valueSerializer = Preconditions.checkNotNull(valueSerializer, "The value serializer cannot be null.");
}
// ------------------------------------------------------------------------
// HashMapSerializer specific properties
// ------------------------------------------------------------------------
public TypeSerializer getKeySerializer() {
return keySerializer;
}
public TypeSerializer getValueSerializer() {
return valueSerializer;
}
// ------------------------------------------------------------------------
// Type Serializer implementation
// ------------------------------------------------------------------------
@Override
public boolean isImmutableType() {
return false;
}
@Override
public TypeSerializer> duplicate() {
TypeSerializer duplicateKeySerializer = keySerializer.duplicate();
TypeSerializer duplicateValueSerializer = valueSerializer.duplicate();
return new HashMapSerializer<>(duplicateKeySerializer, duplicateValueSerializer);
}
@Override
public HashMap createInstance() {
return new HashMap<>();
}
@Override
public HashMap copy(HashMap from) {
HashMap newHashMap = new HashMap<>(from.size());
for (Map.Entry entry : from.entrySet()) {
K newKey = keySerializer.copy(entry.getKey());
V newValue = entry.getValue() == null ? null : valueSerializer.copy(entry.getValue());
newHashMap.put(newKey, newValue);
}
return newHashMap;
}
@Override
public HashMap copy(HashMap from, HashMap reuse) {
return copy(from);
}
@Override
public int getLength() {
return -1; // var length
}
@Override
public void serialize(HashMap map, DataOutputView target) throws IOException {
final int size = map.size();
target.writeInt(size);
for (Map.Entry entry : map.entrySet()) {
keySerializer.serialize(entry.getKey(), target);
if (entry.getValue() == null) {
target.writeBoolean(true);
} else {
target.writeBoolean(false);
valueSerializer.serialize(entry.getValue(), target);
}
}
}
@Override
public HashMap deserialize(DataInputView source) throws IOException {
final int size = source.readInt();
final HashMap map = new HashMap<>(size);
for (int i = 0; i < size; ++i) {
K key = keySerializer.deserialize(source);
boolean isNull = source.readBoolean();
V value = isNull ? null : valueSerializer.deserialize(source);
map.put(key, value);
}
return map;
}
@Override
public HashMap deserialize(HashMap reuse, DataInputView source) throws IOException {
return deserialize(source);
}
@Override
public void copy(DataInputView source, DataOutputView target) throws IOException {
final int size = source.readInt();
target.writeInt(size);
for (int i = 0; i < size; ++i) {
keySerializer.copy(source, target);
boolean isNull = source.readBoolean();
target.writeBoolean(isNull);
if (!isNull) {
valueSerializer.copy(source, target);
}
}
}
@Override
public boolean equals(Object obj) {
return obj == this ||
(obj != null && obj.getClass() == getClass() &&
keySerializer.equals(((HashMapSerializer) obj).getKeySerializer()) &&
valueSerializer.equals(((HashMapSerializer) obj).getValueSerializer()));
}
@Override
public boolean canEqual(Object obj) {
return (obj != null && obj.getClass() == getClass());
}
@Override
public int hashCode() {
return keySerializer.hashCode() * 31 + valueSerializer.hashCode();
}
// --------------------------------------------------------------------------------------------
// Serializer configuration snapshotting & compatibility
// --------------------------------------------------------------------------------------------
@Override
public TypeSerializerConfigSnapshot snapshotConfiguration() {
return new MapSerializerConfigSnapshot<>(keySerializer, valueSerializer);
}
@Override
public CompatibilityResult> ensureCompatibility(TypeSerializerConfigSnapshot configSnapshot) {
if (configSnapshot instanceof MapSerializerConfigSnapshot) {
List, TypeSerializerConfigSnapshot>> previousKvSerializersAndConfigs =
((MapSerializerConfigSnapshot) configSnapshot).getNestedSerializersAndConfigs();
CompatibilityResult keyCompatResult = CompatibilityUtil.resolveCompatibilityResult(
previousKvSerializersAndConfigs.get(0).f0,
UnloadableDummyTypeSerializer.class,
previousKvSerializersAndConfigs.get(0).f1,
keySerializer);
CompatibilityResult valueCompatResult = CompatibilityUtil.resolveCompatibilityResult(
previousKvSerializersAndConfigs.get(1).f0,
UnloadableDummyTypeSerializer.class,
previousKvSerializersAndConfigs.get(1).f1,
valueSerializer);
if (!keyCompatResult.isRequiresMigration() && !valueCompatResult.isRequiresMigration()) {
return CompatibilityResult.compatible();
} else if (keyCompatResult.getConvertDeserializer() != null && valueCompatResult.getConvertDeserializer() != null) {
return CompatibilityResult.requiresMigration(
new HashMapSerializer<>(
new TypeDeserializerAdapter<>(keyCompatResult.getConvertDeserializer()),
new TypeDeserializerAdapter<>(valueCompatResult.getConvertDeserializer())));
}
}
return CompatibilityResult.requiresMigration();
}
}