com.datastax.driver.core

Class CodecUtils

java.lang.Object

com.datastax.driver.core.CodecUtils

public final class CodecUtils
extends Object

A set of utility methods to deal with type conversion, serialization, and to create TypeToken instances.

This class is public because it is accessed from BuiltStatement but its use by client code is not supported.

Method Summary

Modifier and Type	Method and Description
static ByteBuffer	compose(ByteBuffer... buffers) Utility method to assemble different routing key components into a single ByteBuffer.
static ByteBuffer[]	convert(Object[] values, ProtocolVersion protocolVersion, CodecRegistry codecRegistry) Utility method to serialize user-provided values.
static <T> com.google.common.reflect.TypeToken<List<T>>	listOf(Class<T> eltType)
static <T> com.google.common.reflect.TypeToken<List<T>>	listOf(com.google.common.reflect.TypeToken<T> eltType)
static <K,V> com.google.common.reflect.TypeToken<Map<K,V>>	mapOf(Class<K> keyType, Class<V> valueType)
static <K,V> com.google.common.reflect.TypeToken<Map<K,V>>	mapOf(com.google.common.reflect.TypeToken<K> keyType, com.google.common.reflect.TypeToken<V> valueType)
static ByteBuffer	pack(List<ByteBuffer> buffers, int elements, ProtocolVersion version) Utility method that "packs" together a list of ByteBuffers containing serialized collection elements.
static ByteBuffer	readBytes(ByteBuffer bb, int length)
static int	readCollectionSize(ByteBuffer input, ProtocolVersion version) Utility method that reads the collection size.
static ByteBuffer	readCollectionValue(ByteBuffer input, ProtocolVersion version)
static <T> com.google.common.reflect.TypeToken<Set<T>>	setOf(Class<T> eltType)
static <T> com.google.common.reflect.TypeToken<Set<T>>	setOf(com.google.common.reflect.TypeToken<T> eltType)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

listOf

public static <T> com.google.common.reflect.TypeToken<List<T>> listOf(Class<T> eltType)

listOf

public static <T> com.google.common.reflect.TypeToken<List<T>> listOf(com.google.common.reflect.TypeToken<T> eltType)

setOf

public static <T> com.google.common.reflect.TypeToken<Set<T>> setOf(Class<T> eltType)

setOf

public static <T> com.google.common.reflect.TypeToken<Set<T>> setOf(com.google.common.reflect.TypeToken<T> eltType)

mapOf

public static <K,V> com.google.common.reflect.TypeToken<Map<K,V>> mapOf(Class<K> keyType,
                                                                        Class<V> valueType)

mapOf

public static <K,V> com.google.common.reflect.TypeToken<Map<K,V>> mapOf(com.google.common.reflect.TypeToken<K> keyType,
                                                                        com.google.common.reflect.TypeToken<V> valueType)

convert

public static ByteBuffer[] convert(Object[] values,
                                   ProtocolVersion protocolVersion,
                                   CodecRegistry codecRegistry)

Utility method to serialize user-provided values.

This method is useful in situations where there is no metadata available and the underlying CQL type for the values is not known.

This situation happens when a SimpleStatement or a BuiltStatement (Query Builder) contain values; in these places, the driver has no way to determine the right CQL type to use.

This method performs a best-effort heuristic to guess which codec to use. Note that this is not particularly efficient as the codec registry needs to iterate over the registered codecs until it finds a suitable one.

Parameters:

values - The values to convert.

protocolVersion - The protocol version to use.

codecRegistry - The CodecRegistry to use.

Returns:

The converted values.

compose

public static ByteBuffer compose(ByteBuffer... buffers)

Utility method to assemble different routing key components into a single ByteBuffer. Mainly intended for statements that need to generate a routing key out of their current values.

Parameters:

buffers - the components of the routing key.

Returns:

A ByteBuffer containing the serialized routing key

pack

public static ByteBuffer pack(List<ByteBuffer> buffers,
                              int elements,
                              ProtocolVersion version)

Utility method that "packs" together a list of ByteBuffers containing serialized collection elements. Mainly intended for use with collection codecs when serializing collections.

Parameters:

buffers - the collection elements

elements - the total number of elements

version - the protocol version to use

Returns:

The serialized collection

readCollectionSize

public static int readCollectionSize(ByteBuffer input,
                                     ProtocolVersion version)

Utility method that reads the collection size. Mainly intended for collection codecs when deserializing CQL collections.

Parameters:

input - A ByteBuffer containing a serialized CQL collection

version - The protocol version to use.

Returns:

The collection size

readBytes

public static ByteBuffer readBytes(ByteBuffer bb,
                                   int length)

readCollectionValue

public static ByteBuffer readCollectionValue(ByteBuffer input,
                                             ProtocolVersion version)