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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.cql3.functions.types;
import java.nio.ByteBuffer;
import java.util.Iterator;
import java.util.List;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import org.apache.cassandra.cql3.functions.types.exceptions.InvalidTypeException;
import org.apache.cassandra.transport.ProtocolVersion;
import org.apache.cassandra.utils.vint.VIntCoding;
/**
* {@link TypeCodec} for the CQL type {@code vector}. Vectors are represented as {@link List}s for convenience, since
* it's probably easier for UDFs trying to return a newly created vector to create it as a standard Java list, rather
* than using a custom, not-standard vector class.
*
* @param The type of the vector elements.
*/
public abstract class VectorCodec extends TypeCodec>
{
protected final VectorType type;
protected final TypeCodec subtypeCodec;
private VectorCodec(VectorType type, TypeCodec subtypeCodec)
{
super(type, TypeTokens.vectorOf(subtypeCodec.getJavaType()));
this.type = type;
this.subtypeCodec = subtypeCodec;
}
public static VectorCodec of(VectorType type, TypeCodec subtypeCodec)
{
return subtypeCodec.isSerializedSizeFixed()
? new FixedLength<>(type, subtypeCodec)
: new VariableLength<>(type, subtypeCodec);
}
@Override
public List parse(String value) throws InvalidTypeException
{
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL"))
return null;
ImmutableList.Builder values = ImmutableList.builder();
for (String element : Splitter.on(", ").split(value.substring(1, value.length() - 1)))
{
values.add(subtypeCodec.parse(element));
}
return values.build();
}
@Override
public String format(List value) throws InvalidTypeException
{
return value == null ? "NULL" : Iterables.toString(value);
}
/**
* {@link VectorCodec} for vectors of elements using a fixed-length encoding.
*/
private static class FixedLength extends VectorCodec
{
private final int valueLength;
public FixedLength(VectorType type, TypeCodec subtypeCodec)
{
super(type, subtypeCodec);
valueLength = subtypeCodec.serializedSize() * type.getDimensions();
}
@Override
public int serializedSize()
{
return valueLength;
}
@Override
public ByteBuffer serialize(List value, ProtocolVersion protocolVersion) throws InvalidTypeException
{
if (value == null || type.getDimensions() <= 0)
return null;
Iterator values = value.iterator();
ByteBuffer rv = ByteBuffer.allocate(valueLength);
for (int i = 0; i < type.getDimensions(); ++i)
{
ByteBuffer valueBuff = subtypeCodec.serialize(values.next(), protocolVersion);
valueBuff.rewind();
rv.put(valueBuff);
}
rv.flip();
return rv;
}
@Override
public List deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) throws InvalidTypeException
{
if (bytes == null || bytes.remaining() == 0)
return null;
// Determine element size by dividing count of remaining bytes by number of elements.
// This should have a remainder of zero since all elements are of the same fixed size.
int elementSize = Math.floorDiv(bytes.remaining(), type.getDimensions());
assert bytes.remaining() % type.getDimensions() == 0
: String.format("Expected elements of uniform size, observed %d elements with total bytes %d",
type.getDimensions(), bytes.remaining());
ImmutableList.Builder values = ImmutableList.builder();
for (int i = 0; i < type.getDimensions(); ++i)
{
ByteBuffer slice = bytes.slice();
slice.limit(elementSize);
values.add(subtypeCodec.deserialize(slice, protocolVersion));
bytes.position(bytes.position() + elementSize);
}
// Restore the input ByteBuffer to its original state
bytes.rewind();
return values.build();
}
}
/**
* {@link VectorCodec} for vectors of elements using a varaible-length encoding.
*/
private static class VariableLength extends VectorCodec
{
public VariableLength(VectorType type, TypeCodec subtypeCodec)
{
super(type, subtypeCodec);
}
@Override
public ByteBuffer serialize(List values, ProtocolVersion version) throws InvalidTypeException
{
if (values == null)
return null;
assert values.size() == type.getDimensions();
int i = 0;
int outputSize = 0;
ByteBuffer[] buffers = new ByteBuffer[values.size()];
for (E value : values)
{
ByteBuffer bb = subtypeCodec.serialize(value, version);
buffers[i++] = bb;
int elemSize = bb.remaining();
outputSize += elemSize + VIntCoding.computeUnsignedVIntSize(elemSize);
}
ByteBuffer output = ByteBuffer.allocate(outputSize);
for (ByteBuffer bb : buffers)
{
VIntCoding.writeUnsignedVInt32(bb.remaining(), output);
output.put(bb.duplicate());
}
return (ByteBuffer) output.flip();
}
@Override
public List deserialize(ByteBuffer bytes, ProtocolVersion version) throws InvalidTypeException
{
if (bytes == null || bytes.remaining() == 0)
return null;
ByteBuffer input = bytes.duplicate();
ImmutableList.Builder values = ImmutableList.builder();
for (int i = 0; i < type.getDimensions(); i++)
{
int size = VIntCoding.getUnsignedVInt32(input, input.position());
input.position(input.position() + VIntCoding.computeUnsignedVIntSize(size));
ByteBuffer value = size < 0 ? null : CodecUtils.readBytes(input, size);
values.add(subtypeCodec.deserialize(value, version));
}
return values.build();
}
}
}