net.openhft.chronicle.hash.serialization

Interface DataAccess<T>

Type Parameters:

T - the type of objects accessed

All Superinterfaces:

net.openhft.chronicle.bytes.CommonMarshallable, net.openhft.chronicle.wire.Marshallable, net.openhft.chronicle.wire.ReadMarshallable, net.openhft.chronicle.core.io.Resettable, StatefulCopyable<DataAccess<T>>, net.openhft.chronicle.wire.WriteMarshallable, net.openhft.chronicle.wire.WriteValue

public interface DataAccess<T>
extends StatefulCopyable<DataAccess<T>>, net.openhft.chronicle.wire.Marshallable

Strategy of accessing flat byte contents of objects, using a reusable Data object, cached inside the DataAccess instance. This strategy interface is suitable for types of objects, that are already in fact sequences of bytes (byte[], ByteBuffer, etc.) and shouldn't be serialized, and allows to avoid extra data copying. Accessed bytes should be later readable by some BytesReader.

Read DataAccess and SizedReader and custom serialization checklist sections in the Chronicle Map tutorial for more information on this interface, how to implement and use it properly.

See Also:

ChronicleHashBuilder.keyReaderAndDataAccess(SizedReader, DataAccess), ChronicleMapBuilder.valueReaderAndDataAccess(SizedReader, DataAccess)

Field Summary

Fields inherited from interface net.openhft.chronicle.wire.WriteMarshallable

EMPTY

Fields inherited from interface net.openhft.chronicle.wire.ReadMarshallable

DISCARD

Method Summary

Modifier and Type	Method and Description
Data<T>	getData(T instance) Obtain Data accessor to the bytes of the given object.
void	uninit() Clear references to the accessed object (provided in getData(Object) method) in caching fields of this DataAccess or the cached Data object, returned from getData(Object).

Methods inherited from interface net.openhft.chronicle.hash.serialization.StatefulCopyable

copy, copyIfNeeded

Methods inherited from interface net.openhft.chronicle.wire.Marshallable

$equals, $fieldInfos, $hashCode, $toString, copyFrom, copyTo, deepCopy, fromFile, fromFile, fromFileAsMap, fromFileAsMap, fromHexString, fromString, fromString, fromString, getClassName, getField, mergeToMap, readMarshallable, reset, setField, streamFromFile, streamFromFile, usesSelfDescribingMessage, writeMarshallable

Methods inherited from interface net.openhft.chronicle.wire.WriteMarshallable

writeValue

Methods inherited from interface net.openhft.chronicle.wire.ReadMarshallable

unexpectedField

Method Detail

getData

Data<T> getData(@NotNull
                T instance)

Obtain Data accessor to the bytes of the given object. Typically a Data instance should be cached in a field of this DataAccess, so always the same object is returned.

Parameters:

instance - the object to access bytes (serialized form) of

Returns:

an accessor to the bytes of the given object

uninit

void uninit()

Clear references to the accessed object (provided in getData(Object) method) in caching fields of this DataAccess or the cached Data object, returned from getData(Object).

DataAccess is cached itself in thread-local variables for ChronicleHash instances, this method prevents leaking of accessed objects (they are not eligible for garbage collection while there are some references).