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/*
* Copyright (C) 2003-2009 JNode.org
* 2009,2010 Matthias Treydte <mt@waldheinz.de>
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package de.waldheinz.fs;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* This is the abstraction used for a device that can hold a {@link FileSystem}.
*
* @author Ewout Prangsma <epr at jnode.org>
* @author Matthias Treydte <waldheinz at gmail.com>
*/
public interface BlockDevice {
/**
* Gets the total length of this device in bytes.
*
* @return the total number of bytes on this device
* @throws IOException on error getting the size of this device
*/
public abstract long getSize() throws IOException;
/**
* Read a block of data from this device.
*
* @param devOffset the byte offset where to read the data from
* @param dest the destination buffer where to store the data read
* @throws IOException on read error
*/
public abstract void read(long devOffset, ByteBuffer dest)
throws IOException;
/**
* Writes a block of data to this device.
*
* @param devOffset the byte offset where to store the data
* @param src the source {@code ByteBuffer} to write to the device
* @throws ReadOnlyException if this {@code BlockDevice} is read-only
* @throws IOException on write error
* @throws IllegalArgumentException if the {@code devOffset} is negative
* or the write would go beyond the end of the device
* @see #isReadOnly()
*/
public abstract void write(long devOffset, ByteBuffer src)
throws ReadOnlyException, IOException,
IllegalArgumentException;
/**
* Flushes data in caches to the actual storage.
*
* @throws IOException on write error
*/
public abstract void flush() throws IOException;
/**
* Returns the size of a sector on this device.
*
* @return the sector size in bytes
* @throws IOException on error determining the sector size
*/
public int getSectorSize() throws IOException;
/**
* Closes this {@code BlockDevice}. No methods of this device may be
* accesses after this method was called.
*
* @throws IOException on error closing this device
* @see #isClosed()
*/
public void close() throws IOException;
/**
* Checks if this device was already closed. No methods may be called
* on a closed device (except this method).
*
* @return if this device is closed
*/
public boolean isClosed();
/**
* Checks if this {@code BlockDevice} is read-only.
*
* @return if this {@code BlockDevice} is read-only
*/
public boolean isReadOnly();
}
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