/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.io.writecache;
import java.nio.ByteBuffer;
/**
* A backing reader can be provided to a WriteCacheService which can
* use the readRaw callback method as part of an encapsulated caching
* strategy.
*
* @author Martyn Cutcher
*
*/
public interface IBackingReader {
/**
* Read on the backing file, installing the record into the caller's buffer.
* {@link ByteBuffer#remaining()} bytes will be read into the caller's
* buffer, starting at the specified offset in the backing file.
*
* @param fileOffset
* The offset of the first byte to be read (absolute offset on
* the backing file).
* @param dst
* Where to put the data. Bytes will be written at position until
* limit.
*
* @return The caller's buffer, prepared for reading back the installed
* record.
*/
public ByteBuffer readRaw(long fileOffset, ByteBuffer dst);
}