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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.table.runtime.typeutils;
import org.apache.flink.api.common.typeutils.TypeSerializer;
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.Map;
/**
* Base serializer for {@link Map}. 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 flag.
*
* @param The type of the keys in the map.
* @param The type of the values in the map.
* @param The type of the map.
*/
abstract class AbstractMapSerializer> extends TypeSerializer {
private static final long serialVersionUID = 1L;
/** The serializer for the keys in the map. */
final TypeSerializer keySerializer;
/** The serializer for the values in the map. */
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
*/
AbstractMapSerializer(TypeSerializer keySerializer, TypeSerializer valueSerializer) {
Preconditions.checkNotNull(keySerializer, "The key serializer must not be null");
Preconditions.checkNotNull(valueSerializer, "The value serializer must not be null.");
this.keySerializer = keySerializer;
this.valueSerializer = valueSerializer;
}
// ------------------------------------------------------------------------
/**
* Returns the serializer for the keys in the map.
*
* @return The serializer for the keys in the map.
*/
public TypeSerializer getKeySerializer() {
return keySerializer;
}
/**
* Returns the serializer for the values in the map.
*
* @return The serializer for the values in the map.
*/
public TypeSerializer getValueSerializer() {
return valueSerializer;
}
// ------------------------------------------------------------------------
// Type Serializer implementation
// ------------------------------------------------------------------------
@Override
public boolean isImmutableType() {
return false;
}
@Override
public M copy(M from) {
M newMap = createInstance();
for (Map.Entry entry : from.entrySet()) {
K newKey = entry.getKey() == null ? null : keySerializer.copy(entry.getKey());
V newValue = entry.getValue() == null ? null : valueSerializer.copy(entry.getValue());
newMap.put(newKey, newValue);
}
return newMap;
}
@Override
public M copy(M from, M reuse) {
return copy(from);
}
@Override
public int getLength() {
return -1; // var length
}
@Override
public void serialize(M 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 M deserialize(DataInputView source) throws IOException {
final int size = source.readInt();
final M map = createInstance();
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 M deserialize(M 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 o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
AbstractMapSerializer that = (AbstractMapSerializer) o;
return keySerializer.equals(that.keySerializer)
&& valueSerializer.equals(that.valueSerializer);
}
@Override
public int hashCode() {
int result = keySerializer.hashCode();
result = 31 * result + valueSerializer.hashCode();
return result;
}
}