question: BlockId append ( String fileName , IoBuffer buffer ) { try { IoChannel fileChannel = getFileChannel ( fileName ) ; buffer . rewind ( ) ; long newSize = fileChannel . append ( buffer ) ; return new BlockId ( fileName , newSize / BLOCK_SIZE - 1 ) ; } catch ( IOException e ) { e . printStackTrace ( ) ; return null ; } }
target:  Appends the contents of a byte buffer to the end of the specified file.