Class VersionFieldSerializer<T>

java.lang.Object

com.esotericsoftware.kryo.Serializer<T>

com.esotericsoftware.kryo.serializers.FieldSerializer<T, FieldSerializerConfig>

com.esotericsoftware.kryo.serializers.VersionFieldSerializer<T>

All Implemented Interfaces:

Comparator<FieldSerializer.CachedField>

public class VersionFieldSerializer<T>
extends FieldSerializer<T, FieldSerializerConfig>

Serializes objects using direct field assignment, with versioning backward compatibility. Allows fields to have a @Since(int) annotation to indicate the version they were added. For a particular field, the value in @Since should never change once created. This is less flexible than FieldSerializer, which can handle most classes without needing annotations, but it provides backward compatibility. This means that new fields can be added, but removing, renaming or changing the type of any field will invalidate previous serialized bytes. VersionFieldSerializer has very little overhead (a single additional varint) compared to FieldSerializer. Forward compatibility is not supported.

See Also:

• TaggedFieldSerializer

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static @interface	VersionFieldSerializer.Since	Incremental modification of serialized objects must add VersionFieldSerializer.Since for new fields.

Nested classes/interfaces inherited from class FieldSerializer

FieldSerializer.Bind, FieldSerializer.CachedField<X>, FieldSerializer.CachedFieldFactory, FieldSerializer.CachedFieldNameStrategy, FieldSerializer.Optional

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	compatible
private int[]	fieldVersion
private int	typeVersion

Fields inherited from class FieldSerializer

access, asmFieldFactory, componentType, config, kryo, objectFieldFactory, removedFields, type, typeParameters

Constructor Summary

Constructors

Constructor	Description
VersionFieldSerializer(Kryo kryo, Class type)
VersionFieldSerializer(Kryo kryo, Class type, boolean compatible)

Method Summary

Modifier and Type	Method	Description
protected void	initializeCachedFields()
T	read(Kryo kryo, Input input, Class<T> type)	Reads bytes and returns a new object of the specified concrete type.
void	removeField(FieldSerializer.CachedField field)	Removes a field so that it won't be serialized.
void	removeField(String fieldName)	Removes a field so that it won't be serialized.
void	write(Kryo kryo, Output output, T object)	This method can be called for different fields having the same type.

Methods inherited from class FieldSerializer

compare, copy, create, createCopy, getCachedFieldName, getConfig, getCopyTransient, getField, getFields, getGenerics, getGenericsScope, getKryo, getSerializeTransient, getTransientFields, getType, newCachedField, newMatchingCachedField, rebuildCachedFields, rebuildCachedFields, setCopyTransient, setFieldsAsAccessible, setFieldsCanBeNull, setFixedFieldTypes, setGenerics, setIgnoreSyntheticFields, setOptimizedGenerics, setSerializeTransient

Methods inherited from class Serializer

getAcceptsNull, isImmutable, setAcceptsNull, setImmutable

Methods inherited from class Object

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

Methods inherited from interface Comparator

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Details

typeVersion

private int typeVersion

fieldVersion

private int[] fieldVersion

compatible

private boolean compatible

Constructor Details

VersionFieldSerializer

public VersionFieldSerializer(Kryo kryo,
 Class type)

VersionFieldSerializer

public VersionFieldSerializer(Kryo kryo,
 Class type,
 boolean compatible)

Method Details

initializeCachedFields

protected void initializeCachedFields()

Overrides:

initializeCachedFields in class FieldSerializer<T, FieldSerializerConfig>

removeField

public void removeField(String fieldName)

Description copied from class: FieldSerializer

Removes a field so that it won't be serialized.

Overrides:

removeField in class FieldSerializer<T, FieldSerializerConfig>

removeField

public void removeField(FieldSerializer.CachedField field)

Description copied from class: FieldSerializer

Removes a field so that it won't be serialized.

Overrides:

removeField in class FieldSerializer<T, FieldSerializerConfig>

write

public void write(Kryo kryo,
 Output output,
 T object)

Description copied from class: FieldSerializer

This method can be called for different fields having the same type. Even though the raw type is the same, if the type is generic, it could happen that different concrete classes are used to instantiate it. Therefore, in case of different instantiation parameters, the fields analysis should be repeated. TODO: Cache serializer instances generated for a given set of generic parameters. Reuse it later instead of recomputing every time.

Overrides:

write in class FieldSerializer<T, FieldSerializerConfig>

Parameters:

object - May be null if Serializer.getAcceptsNull() is true.

read

public T read(Kryo kryo,
 Input input,
 Class<T> type)

Description copied from class: Serializer

Reads bytes and returns a new object of the specified concrete type.

Before Kryo can be used to read child objects, Kryo.reference(Object) must be called with the parent object to ensure it can be referenced by the child objects. Any serializer that uses Kryo to read a child object may need to be reentrant.

This method should not be called directly, instead this serializer can be passed to Kryo read methods that accept a serialier.

Overrides:

read in class FieldSerializer<T, FieldSerializerConfig>

Returns:

May be null if Serializer.getAcceptsNull() is true.