/*
* 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 com.google.common.base.Preconditions;
import io.netty.channel.DefaultFileRegion;
import java.io.File;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
/**
* A DataBuffer with the underlying data being a {@link FileChannel}.
*/
public final class DataFileChannel implements DataBuffer {
private final File mFile;
private final long mOffset;
private final long mLength;
/**
*
* @param file The file
* @param offset The offset into the FileChannel
* @param length The length of the data to read
*/
public DataFileChannel(File file, long offset, long length) {
mFile = Preconditions.checkNotNull(file, "file");
mOffset = offset;
mLength = length;
}
@Override
public Object getNettyOutput() {
return new DefaultFileRegion(mFile, mOffset, mLength);
}
@Override
public long getLength() {
return mLength;
}
@Override
public ByteBuffer getReadOnlyByteBuffer() {
throw new UnsupportedOperationException(
"DataFileChannel#getReadOnlyByteBuffer is not implemented.");
}
@Override
public void readBytes(byte[] dst, int dstIndex, int length) {
throw new UnsupportedOperationException("DataFileChannel#readBytes is not implemented.");
}
@Override
public int readableBytes() {
throw new UnsupportedOperationException("DataFileChannel#readableBytes is not implemented.");
}
@Override
public void release() {
// Nothing we need to release explicitly, let GC take care of all objects.
}
}