com.apple.foundationdb.record.provider.common

Interface RecordSerializer<M extends Message>

Type Parameters:

M - type used to represent stored records

All Known Implementing Classes:

DynamicMessageRecordSerializer, MessageBuilderRecordSerializer, MessageBuilderRecordSerializerBase, TransformedRecordSerializer, TransformedRecordSerializerJCE, TypedRecordSerializer

@API(value=MAINTAINED)
public interface RecordSerializer<M extends Message>

A converter between a Protobuf record and a byte string stored in one or more values in the FDB key-value store.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	RecordSerializer.Counts Instrumentation counts related to record serialization.
static class	RecordSerializer.Events Instrumentation events related to record serialization.

Method Summary

Modifier and Type	Method and Description
M	deserialize(RecordMetaData metaData, Tuple primaryKey, byte[] serialized, StoreTimer timer) Convert a byte array to a Protobuf record.
byte[]	serialize(RecordMetaData metaData, RecordType recordType, M record, StoreTimer timer) Convert a Protobuf record to bytes.
RecordSerializer<Message>	widen() Convert this typed record serializer to an untyped one.

Method Detail

serialize

@Nonnull
byte[] serialize(@Nonnull
                          RecordMetaData metaData,
                          @Nonnull
                          RecordType recordType,
                          @Nonnull
                          M record,
                          @Nullable
                          StoreTimer timer)

Convert a Protobuf record to bytes. While Protobuf messages provide their own MessageLite.toByteArray() method for serialization, record stores may elect to first wrap the raw Protobuf record in another wrapping type or perform additional transformations like encrypt or compress records. Implementors of this interface can control how exactly which transformations are done, with the main constraint being that whatever operation is done should be reversible by calling the deserialize() method on those bytes. Implementors should also be careful as they evolve this method that the deserialize method is still able to read older data unless they are certain that any record store that used the older implementation has since been cleared out or migrated to a newer format.

Parameters:

metaData - the store's meta-data

recordType - the record type of the message

record - the Protobuf record to serialize

timer - a timer used to instrument serialization

Returns:

the serialized record

deserialize

@Nonnull
M deserialize(@Nonnull
                       RecordMetaData metaData,
                       @Nonnull
                       Tuple primaryKey,
                       @Nonnull
                       byte[] serialized,
                       @Nullable
                       StoreTimer timer)

Convert a byte array to a Protobuf record. This should be the inverse of the serialize() method.

Parameters:

metaData - the store's meta-data

primaryKey - the primary key of the record

serialized - the serialized bytes

timer - a timer used to instrument deserialization

Returns:

the deserialized record

widen

@Nonnull
RecordSerializer<Message> widen()

Convert this typed record serializer to an untyped one.

• If this serializer wraps another serializer, for example, because it does compressions, then widen that serializer and return the result wrapped equivalently.
• If this serializer parses messages in a type-sensitive way, return the closest general purpose way.
• If this serializer is inherently bound to its type parameter, throw an exception.

If a FDBTypedRecordStore is created without calling FDBTypedRecordStore.Builder.setUntypedSerializer(com.apple.foundationdb.record.provider.common.RecordSerializer<com.google.protobuf.Message>), then in order to make the untyped record store that is paired with the typed store (used, for instance, to rebuild indexes), the given typed serializer will be widened by calling this method.

Returns:

a new serializer that works the same way but handles all record types.