public void wrap(final FileChannel fileChannel, final long offset, final long length)
    {
        unmap();
        this.fileChannel = fileChannel;
        map(offset, length);
    }
public void wrap ( final FileChannel fileChannel , final long offset , final long length ) { unmap ( ) ; this . fileChannel = fileChannel ; map ( offset , length ) ; }
Remap the buffer based on a new file, offset, and a length

@param fileChannel the file to map
@param offset      the offset of the file to start the mapping
@param length      of the buffer from the given address