org.apache.cassandra.serializers.MapSerializer Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of cassandra-clientutil Show documentation
Show all versions of cassandra-clientutil Show documentation
The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.serializers;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.util.*;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.transport.Server;
import org.apache.cassandra.utils.Pair;
public class MapSerializer extends CollectionSerializer>
{
// interning instances
private static final Map, TypeSerializer>, MapSerializer> instances = new HashMap, TypeSerializer>, MapSerializer>();
public final TypeSerializer keys;
public final TypeSerializer values;
public static synchronized MapSerializer getInstance(TypeSerializer keys, TypeSerializer values)
{
Pair, TypeSerializer> p = Pair., TypeSerializer>create(keys, values);
MapSerializer t = instances.get(p);
if (t == null)
{
t = new MapSerializer(keys, values);
instances.put(p, t);
}
return t;
}
private MapSerializer(TypeSerializer keys, TypeSerializer values)
{
this.keys = keys;
this.values = values;
}
public List serializeValues(Map map)
{
List buffers = new ArrayList<>(map.size() * 2);
for (Map.Entry entry : map.entrySet())
{
buffers.add(keys.serialize(entry.getKey()));
buffers.add(values.serialize(entry.getValue()));
}
return buffers;
}
public int getElementCount(Map value)
{
return value.size();
}
public void validateForNativeProtocol(ByteBuffer bytes, int version)
{
try
{
ByteBuffer input = bytes.duplicate();
int n = readCollectionSize(input, version);
for (int i = 0; i < n; i++)
{
keys.validate(readValue(input, version));
values.validate(readValue(input, version));
}
if (input.hasRemaining())
throw new MarshalException("Unexpected extraneous bytes after map value");
}
catch (BufferUnderflowException e)
{
throw new MarshalException("Not enough bytes to read a set");
}
}
public Map deserializeForNativeProtocol(ByteBuffer bytes, int version)
{
try
{
ByteBuffer input = bytes.duplicate();
int n = readCollectionSize(input, version);
if (n < 0)
throw new MarshalException("The data cannot be deserialized as a map");
// If the received bytes are not corresponding to a map, n might be a huge number.
// In such a case we do not want to initialize the map with that initialCapacity as it can result
// in an OOM when put is called (see CASSANDRA-12618). On the other hand we do not want to have to resize
// the map if we can avoid it, so we put a reasonable limit on the initialCapacity.
Map m = new LinkedHashMap(Math.min(n, 256));
for (int i = 0; i < n; i++)
{
ByteBuffer kbb = readValue(input, version);
keys.validate(kbb);
ByteBuffer vbb = readValue(input, version);
values.validate(vbb);
m.put(keys.deserialize(kbb), values.deserialize(vbb));
}
if (input.hasRemaining())
throw new MarshalException("Unexpected extraneous bytes after map value");
return m;
}
catch (BufferUnderflowException e)
{
throw new MarshalException("Not enough bytes to read a map");
}
}
/**
* Given a serialized map, gets the value associated with a given key.
* @param serializedMap a serialized map
* @param serializedKey a serialized key
* @param keyType the key type for the map
* @return the value associated with the key if one exists, null otherwise
*/
public ByteBuffer getSerializedValue(ByteBuffer serializedMap, ByteBuffer serializedKey, AbstractType keyType)
{
try
{
ByteBuffer input = serializedMap.duplicate();
int n = readCollectionSize(input, Server.VERSION_3);
for (int i = 0; i < n; i++)
{
ByteBuffer kbb = readValue(input, Server.VERSION_3);
ByteBuffer vbb = readValue(input, Server.VERSION_3);
int comparison = keyType.compare(kbb, serializedKey);
if (comparison == 0)
return vbb;
else if (comparison > 0)
// since the map is in sorted order, we know we've gone too far and the element doesn't exist
return null;
}
return null;
}
catch (BufferUnderflowException e)
{
throw new MarshalException("Not enough bytes to read a map");
}
}
public String toString(Map value)
{
StringBuilder sb = new StringBuilder();
boolean isFirst = true;
for (Map.Entry element : value.entrySet())
{
if (isFirst)
isFirst = false;
else
sb.append("; ");
sb.append('(');
sb.append(keys.toString(element.getKey()));
sb.append(", ");
sb.append(values.toString(element.getValue()));
sb.append(')');
}
return sb.toString();
}
public Class> getType()
{
return (Class)Map.class;
}
}