com.datastax.driver.extras.codecs

Class MappingCodec<O,I>

java.lang.Object

com.datastax.driver.core.TypeCodec<O>

com.datastax.driver.extras.codecs.MappingCodec<O,I>

Type Parameters:

O - The "outer" (user-facing) Java type

I - The "inner" (Cassandra-facing, intermediary) Java type

Direct Known Subclasses:

OptionalCodec, OptionalCodec

public abstract class MappingCodec<O,I>
extends com.datastax.driver.core.TypeCodec<O>

An abstract TypeCodec that maps a Java Pojo to another Java object that can in turn be serialized into a CQL type. This can serve as a base for libraries dealing with Pojo mappings.

This codec can be seen as a convenience base class for libraries dealing with Pojo-to-Pojo mappings, but it comes with a performance penalty: each Java object is serialized in two steps: first to an intermediate object, and then to a ByteBuffer, which means that each serialization actually incurs in two potentially expensive operations being carried.

If such operations are really expensive, and your mapping library is capable of serializing objects directly to ByteBuffers, consider writing your own codec instead of using this one.

Nested Class Summary

Nested classes/interfaces inherited from class com.datastax.driver.core.TypeCodec

com.datastax.driver.core.TypeCodec.AbstractCollectionCodec<E,C extends Collection<E>>, com.datastax.driver.core.TypeCodec.AbstractMapCodec<K,V>, com.datastax.driver.core.TypeCodec.AbstractTupleCodec<T>, com.datastax.driver.core.TypeCodec.AbstractUDTCodec<T>, com.datastax.driver.core.TypeCodec.PrimitiveBooleanCodec, com.datastax.driver.core.TypeCodec.PrimitiveByteCodec, com.datastax.driver.core.TypeCodec.PrimitiveDoubleCodec, com.datastax.driver.core.TypeCodec.PrimitiveFloatCodec, com.datastax.driver.core.TypeCodec.PrimitiveIntCodec, com.datastax.driver.core.TypeCodec.PrimitiveLongCodec, com.datastax.driver.core.TypeCodec.PrimitiveShortCodec

Field Summary

Fields

Modifier and Type	Field and Description
protected com.datastax.driver.core.TypeCodec<I>	innerCodec

Fields inherited from class com.datastax.driver.core.TypeCodec

cqlType, javaType

Constructor Summary

Constructors

Constructor and Description
MappingCodec(com.datastax.driver.core.TypeCodec<I> innerCodec, Class<O> javaType)
MappingCodec(com.datastax.driver.core.TypeCodec<I> innerCodec, TypeToken<O> javaType)

Method Summary

Modifier and Type	Method and Description
O	deserialize(ByteBuffer bytes, com.datastax.driver.core.ProtocolVersion protocolVersion)
protected abstract O	deserialize(I value)
String	format(O value)
O	parse(String value)
protected abstract I	serialize(O value)
ByteBuffer	serialize(O value, com.datastax.driver.core.ProtocolVersion protocolVersion)

Methods inherited from class com.datastax.driver.core.TypeCodec

accepts, accepts, accepts, accepts, ascii, bigint, blob, cboolean, cdouble, cfloat, cint, counter, custom, date, decimal, getCqlType, getJavaType, inet, list, map, set, smallInt, time, timestamp, timeUUID, tinyInt, toString, tuple, userType, uuid, varchar, varint

Methods inherited from class java.lang.Object

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

Field Detail

innerCodec

protected final com.datastax.driver.core.TypeCodec<I> innerCodec

Constructor Detail

MappingCodec

public MappingCodec(com.datastax.driver.core.TypeCodec<I> innerCodec,
                    Class<O> javaType)

MappingCodec

public MappingCodec(com.datastax.driver.core.TypeCodec<I> innerCodec,
                    TypeToken<O> javaType)

Method Detail

serialize

public ByteBuffer serialize(O value,
                            com.datastax.driver.core.ProtocolVersion protocolVersion)
                     throws com.datastax.driver.core.exceptions.InvalidTypeException

Specified by:

serialize in class com.datastax.driver.core.TypeCodec<O>

Throws:

com.datastax.driver.core.exceptions.InvalidTypeException

deserialize

public O deserialize(ByteBuffer bytes,
                     com.datastax.driver.core.ProtocolVersion protocolVersion)
              throws com.datastax.driver.core.exceptions.InvalidTypeException

Specified by:

deserialize in class com.datastax.driver.core.TypeCodec<O>

Throws:

com.datastax.driver.core.exceptions.InvalidTypeException

parse

public O parse(String value)
        throws com.datastax.driver.core.exceptions.InvalidTypeException

Specified by:

parse in class com.datastax.driver.core.TypeCodec<O>

Throws:

com.datastax.driver.core.exceptions.InvalidTypeException

format

public String format(O value)
              throws com.datastax.driver.core.exceptions.InvalidTypeException

Specified by:

format in class com.datastax.driver.core.TypeCodec<O>

Throws:

com.datastax.driver.core.exceptions.InvalidTypeException

deserialize

protected abstract O deserialize(I value)

serialize

protected abstract I serialize(O value)