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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.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.ByteBufferAccessor;
import org.apache.cassandra.db.marshal.ValueAccessor;
import org.apache.cassandra.db.marshal.ValueComparators;
public class SetSerializer extends AbstractMapSerializer>
{
// interning instances
@SuppressWarnings("rawtypes")
private static final ConcurrentMap, SetSerializer> instances = new ConcurrentHashMap<>();
public final TypeSerializer elements;
private final ValueComparators comparators;
@SuppressWarnings("unchecked")
public static SetSerializer getInstance(TypeSerializer elements, ValueComparators comparators)
{
SetSerializer t = instances.get(elements);
if (t == null)
t = instances.computeIfAbsent(elements, k -> new SetSerializer<>(k, comparators) );
return t;
}
public SetSerializer(TypeSerializer elements, ValueComparators comparators)
{
super(false);
this.elements = elements;
this.comparators = comparators;
}
@Override
public List serializeValues(Set values)
{
List buffers = new ArrayList<>(values.size());
for (T value : values)
buffers.add(elements.serialize(value));
buffers.sort(comparators.buffer);
return buffers;
}
@Override
public int getElementCount(Set value)
{
return value.size();
}
@Override
public void validate(V input, ValueAccessor accessor)
{
if (accessor.isEmpty(input))
throw new MarshalException("Not enough bytes to read a set");
try
{
// Empty values are still valid.
if (accessor.isEmpty(input)) return;
int n = readCollectionSize(input, accessor);
int offset = sizeOfCollectionSize();
for (int i = 0; i < n; i++)
{
V value = readNonNullValue(input, accessor, offset);
offset += sizeOfValue(value, accessor);
elements.validate(value, accessor);
}
if (!accessor.isEmptyFromOffset(input, offset))
throw new MarshalException("Unexpected extraneous bytes after set value");
}
catch (BufferUnderflowException | IndexOutOfBoundsException e)
{
throw new MarshalException("Not enough bytes to read a set");
}
}
@Override
public Set deserialize(V input, ValueAccessor accessor)
{
try
{
int n = readCollectionSize(input, accessor);
int offset = sizeOfCollectionSize();
if (n < 0)
throw new MarshalException("The data cannot be deserialized as a set");
// If the received bytes are not corresponding to a set, n might be a huge number.
// In such a case we do not want to initialize the set with that initialCapacity as it can result
// in an OOM when add is called (see CASSANDRA-12618). On the other hand we do not want to have to resize
// the set if we can avoid it, so we put a reasonable limit on the initialCapacity.
Set l = new LinkedHashSet<>(Math.min(n, 256));
for (int i = 0; i < n; i++)
{
V value = readNonNullValue(input, accessor, offset);
offset += sizeOfValue(value, accessor);
elements.validate(value, accessor);
l.add(elements.deserialize(value, accessor));
}
if (!accessor.isEmptyFromOffset(input, offset))
throw new MarshalException("Unexpected extraneous bytes after set value");
return l;
}
catch (BufferUnderflowException | IndexOutOfBoundsException e)
{
throw new MarshalException("Not enough bytes to read a set");
}
}
@Override
public String toString(Set value)
{
StringBuilder sb = new StringBuilder();
sb.append('{');
boolean isFirst = true;
for (T element : value)
{
if (isFirst)
{
isFirst = false;
}
else
{
sb.append(", ");
}
sb.append(elements.toString(element));
}
sb.append('}');
return sb.toString();
}
@Override
@SuppressWarnings({ "rawtypes", "unchecked" })
public Class> getType()
{
return (Class) Set.class;
}
@Override
public ByteBuffer getSerializedValue(ByteBuffer input, ByteBuffer key, AbstractType comparator)
{
try
{
int n = readCollectionSize(input, ByteBufferAccessor.instance);
int offset = sizeOfCollectionSize();
for (int i = 0; i < n; i++)
{
ByteBuffer value = readValue(input, ByteBufferAccessor.instance, offset);
offset += sizeOfValue(value, ByteBufferAccessor.instance);
int comparison = comparator.compareForCQL(value, key);
if (comparison == 0)
return value;
else if (comparison > 0)
// since the set is in sorted order, we know we've gone too far and the element doesn't exist
return null;
// else, we're before the element so continue
}
return null;
}
catch (BufferUnderflowException | IndexOutOfBoundsException e)
{
throw new MarshalException("Not enough bytes to read a set");
}
}
}