package hdfs.jsr203;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.channels.WritableByteChannel;

public class HadoopFileChannel extends FileChannel {

    private SeekableByteChannel internalChannel;
    
    public HadoopFileChannel(SeekableByteChannel newByteChannel) {
        this.internalChannel = newByteChannel;
    }

    @Override
    public int read(ByteBuffer dst) throws IOException {
        return this.internalChannel.read(dst);
    }

    @Override
    public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public int write(ByteBuffer src) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public long position() throws IOException {
        return this.internalChannel.position();
    }

    @Override
    public FileChannel position(long newPosition) throws IOException {
        this.internalChannel.position(newPosition);
        return this;
    }

    @Override
    public long size() throws IOException {
        return this.internalChannel.size();
    }

    @Override
    public FileChannel truncate(long size) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public void force(boolean metaData) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public long transferTo(long position, long count, WritableByteChannel target) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public long transferFrom(ReadableByteChannel src, long position, long count) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public int read(ByteBuffer dst, long position) throws IOException {
        this.internalChannel = this.internalChannel.position(position);
        return this.internalChannel.read(dst);
    }

    @Override
    public int write(ByteBuffer src, long position) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public MappedByteBuffer map(MapMode mode, long position, long size) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public FileLock lock(long position, long size, boolean shared) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    public FileLock tryLock(long position, long size, boolean shared) throws IOException {
        throw new IOException("Imcomplete implementation");
    }

    @Override
    protected void implCloseChannel() throws IOException {
        this.internalChannel.close();
    }

}

Add basic support for FileChannel
Add basic support for FileChannel