com.datastax.driver.core

Class TypeCodec.MapCodec<K,V>

java.lang.Object

com.datastax.driver.core.TypeCodec<Map<K,V>>

com.datastax.driver.core.TypeCodec.MapCodec<K,V>

Enclosing class:

TypeCodec<T>

public static class TypeCodec.MapCodec<K,V>
extends TypeCodec<Map<K,V>>

This codec maps a CQL map type to a Java Map.

Nested Class Summary

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

TypeCodec.AbstractUUIDCodec, TypeCodec.AsciiCodec, TypeCodec.BigintCodec, TypeCodec.BlobCodec, TypeCodec.BooleanCodec, TypeCodec.CollectionCodec<E,C extends Collection<E>>, TypeCodec.CounterCodec, TypeCodec.CustomCodec, TypeCodec.DateCodec, TypeCodec.DecimalCodec, TypeCodec.DoubleCodec, TypeCodec.EnumIntCodec<E extends Enum<E>>, TypeCodec.EnumStringCodec<E extends Enum<E>>, TypeCodec.FloatCodec, TypeCodec.InetCodec, TypeCodec.IntCodec, TypeCodec.ListCodec<T>, TypeCodec.LongCodec, TypeCodec.MapCodec<K,V>, TypeCodec.MappingCodec<T,U>, TypeCodec.PrimitiveBooleanCodec, TypeCodec.PrimitiveByteCodec, TypeCodec.PrimitiveDoubleCodec, TypeCodec.PrimitiveFloatCodec, TypeCodec.PrimitiveIntCodec, TypeCodec.PrimitiveLongCodec, TypeCodec.PrimitiveShortCodec, TypeCodec.SetCodec<T>, TypeCodec.SmallIntCodec, TypeCodec.StringCodec, TypeCodec.StringParsingCodec<T>, TypeCodec.TimeCodec, TypeCodec.TimestampCodec, TypeCodec.TimeUUIDCodec, TypeCodec.TinyIntCodec, TypeCodec.TupleCodec, TypeCodec.UDTCodec, TypeCodec.UUIDCodec, TypeCodec.VarcharCodec, TypeCodec.VarintCodec

Field Summary

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

cqlType, javaType

Constructor Summary

Constructors

Constructor and Description
MapCodec(TypeCodec<K> keyCodec, TypeCodec<V> valueCodec)

Method Summary

Modifier and Type	Method and Description
boolean	accepts(Object value) Return true if this codec is capable of serializing the given object.
Map<K,V>	deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) Deserialize the given ByteBuffer instance according to the CQL type handled by this codec.
String	format(Map<K,V> value) Format the given value as a valid CQL literal according to the CQL type handled by this codec.
Map<K,V>	parse(String value) Parse the given CQL literal into an instance of the Java type handled by this codec.
ByteBuffer	serialize(Map<K,V> value, ProtocolVersion protocolVersion) Serialize the given value according to the CQL type handled by this codec.

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

accepts, accepts, equals, getCqlType, getJavaType, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MapCodec

public MapCodec(TypeCodec<K> keyCodec,
                TypeCodec<V> valueCodec)

Method Detail

accepts

public boolean accepts(Object value)

Description copied from class: TypeCodec

Return true if this codec is capable of serializing the given object. Note that the object's Java type is inferred from the object' runtime (raw) type, contrary to TypeCodec.accepts(TypeToken) which is capable of handling generic types.

This method is intended mostly to be used by the QueryBuilder when no type information is available when the codec is used.

Implementation notes:

1. The base implementation provided here can only handle non-parameterized types; codecs handling parameterized types, such as collection types, must override this method and perform some sort of "manual" inspection of the actual type parameters.
2. Similarly, codecs that only accept a partial subset of all possible values, such as TypeCodec.TimeUUIDCodec or TypeCodec.AsciiCodec, must override this method and manually inspect the object to check if it complies or not with the codec's limitations.

Overrides:

accepts in class TypeCodec<Map<K,V>>

Parameters:

value - The Java type this codec should serialize from and deserialize to; cannot be null.

Returns:

true if the codec is capable of serializing the given javaType, and false otherwise.

parse

public Map<K,V> parse(String value)

Description copied from class: TypeCodec

Parse the given CQL literal into an instance of the Java type handled by this codec. Implementors should take care of unquoting and unescaping the given CQL string where applicable. Null values and empty Strings should be accepted, as weel as the string "NULL"; in most cases, implementations should interpret these inputs has equivalent to a null reference.

Specified by:

parse in class TypeCodec<Map<K,V>>

Parameters:

value - The CQL string to parse, may be null or empty.

Returns:

An instance of T; may be null on a null input.

format

public String format(Map<K,V> value)

Description copied from class: TypeCodec

Format the given value as a valid CQL literal according to the CQL type handled by this codec. Implementors should take care of quoting and escaping the resulting CQL literal where applicable. Null values should be accepted; in most cases, implementations should return the CQL keyword "NULL" for null inputs.

Specified by:

format in class TypeCodec<Map<K,V>>

Parameters:

value - An instance of T; may be null.

Returns:

CQL string

serialize

public ByteBuffer serialize(Map<K,V> value,
                            ProtocolVersion protocolVersion)

Description copied from class: TypeCodec

Serialize the given value according to the CQL type handled by this codec.

Implementation notes:

1. Null values should be gracefully handled and no exception should be raised; these should be considered as the equivalent of a NULL CQL value;
2. Codecs for CQL collection types should not permit null elements;
3. Codecs for CQL collection types should treat a null input as the equivalent of an empty collection.

Specified by:

serialize in class TypeCodec<Map<K,V>>

Parameters:

value - An instance of T; may be null.

protocolVersion - the protocol version to use when serializing bytes. In most cases, the proper value to provide for this argument is the value returned by ProtocolOptions.getProtocolVersion() (which is the protocol version in use by the driver).

Returns:

A ByteBuffer instance containing the serialized form of T

deserialize

public Map<K,V> deserialize(ByteBuffer bytes,
                            ProtocolVersion protocolVersion)

Description copied from class: TypeCodec

Deserialize the given ByteBuffer instance according to the CQL type handled by this codec.

Implementation notes:

1. Null or empty buffers should be gracefully handled and no exception should be raised; these should be considered as the equivalent of a NULL CQL value and, in most cases, should map to null or a default value for the corresponding Java type, if applicable;
2. Codecs for CQL collection types should return unmodifiable collections;
3. Codecs for CQL collection types should avoid returning null; they should return empty collections instead.

Specified by:

deserialize in class TypeCodec<Map<K,V>>

Parameters:

bytes - A ByteBuffer instance containing the serialized form of T; may be null or empty.

protocolVersion - the protocol version to use when serializing bytes. In most cases, the proper value to provide for this argument is the value returned by ProtocolOptions.getProtocolVersion() (which is the protocol version in use by the driver).

Returns:

An instance of T