net.openhft.chronicle.hash.serialization.SizedReader Maven / Gradle / Ivy
/*
* Copyright 2012-2018 Chronicle Map Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.openhft.chronicle.hash.serialization;
import net.openhft.chronicle.bytes.Bytes;
import net.openhft.chronicle.hash.ChronicleHash;
import net.openhft.chronicle.hash.ChronicleHashBuilder;
import net.openhft.chronicle.map.ChronicleMapBuilder;
import net.openhft.chronicle.wire.Marshallable;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
/**
* Deserializer of objects from bytes, pairing {@link SizedWriter}, i. e. assuming the length
* of the serialized form isn't written in the beginning of the serialized form itself, but managed
* by {@link ChronicleHash} implementation and passed to the reading methods.
*
*
Read {@code
* SizedWriter} and {@code SizedReader},
* {@link DataAccess}
* and {@code SizedReader} and
* custom
* serialization checklist sections in the Chronicle Map tutorial for more information on this
* interface, how to implement and use it properly.
*
* @param the type of the object deserialized
* @see SizedWriter
* @see ChronicleHashBuilder#keyMarshallers(SizedReader, SizedWriter)
* @see ChronicleHashBuilder#keyReaderAndDataAccess(SizedReader, DataAccess)
* @see ChronicleMapBuilder#valueMarshallers(SizedReader, SizedWriter)
* @see ChronicleMapBuilder#valueReaderAndDataAccess(SizedReader, DataAccess)
*/
public interface SizedReader extends Marshallable {
/**
* Reads and returns the object from {@link Bytes#readPosition()} (i. e. the current position)
* to {@code Bytes.readPosition() + size} in the given {@code in}. Should attempt to reuse the
* given {@code using} object, i. e. to read the deserialized data into the given object. If it
* is possible, this objects then returned from this method. If it is impossible for any reason,
* a new object should be created and returned. The given {@code using} object could be {@code
* null}, in this case read() should always create a new object.
*
*
This method should increment the position in the given {@code Bytes} by the given {@code
* size}.
*
* @param in the {@code Bytes} to read the object from
* @param size the size of the serialized form of the returned object
* @param using the object to read the deserialized data into, could be {@code null}
* @return the object read from the bytes, either reused or newly created
*/
@NotNull
T read(Bytes in, long size, @Nullable T using);
}