/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.network.protocol.databuffer;
import java.nio.ByteBuffer;
/**
* This interface is a simple wrapper for the optional data that an RPCMessage may have. This allows
* subclasses to support different representations of the data.
*/
public interface DataBuffer {
/**
* Returns an object for writing to a netty channel.
*
* @return the object to output to Netty. Must be ByteBuf or FileRegion
*/
Object getNettyOutput();
/**
* Returns the length of the data.
*
* @return the length of the data in bytes
*/
long getLength();
/**
* Returns a {@link ByteBuffer} for read-only access to the data.
*
* @return a read-only ByteBuffer representing the data
*/
ByteBuffer getReadOnlyByteBuffer();
/**
* Transfers this buffer's data to the specified destination starting at
* the current {@code readerIndex} and increases the {@code readerIndex}
* by the number of the transferred bytes (= {@code length}).
*
* @param dst the destination
* @param dstIndex the first index of the destination
* @param length the number of bytes to transfer
*/
void readBytes(byte[] dst, int dstIndex, int length);
/**
* @return the number of readable bytes remaining
*/
int readableBytes();
/**
* Release the underlying buffer of this DataBuffer if no longer needed.
*/
void release();
}