----------------------------------------
> From: johnlu...@hotmail.com
> To: user@cassandra.apache.org
> Subject: RE: cassandra hadoop reducer writing to CQL3 - primary key - must it
> be text type?
> Date: Wed, 9 Oct 2013 18:33:13 -0400
>
> reduce method :
>
> public void reduce(LongWritable writableRecid, Iterable<LongWritable>
> values, Context context) throws IOException, InterruptedException
> {
> Long sum = 0L;
> Long recordid = writableRecid.get();
> List<ByteBuffer> vbles = null;
> byte[] longByterray = new byte[8];
> for(int i= 0; i < 8; i++) {
> longByterray[i] = (byte)(recordid>> (i * 8));
> }
> ByteBuffer recordIdByteBuf = ByteBuffer.allocate(8);
> recordIdByteBuf.wrap(longByterray);
> keys.put("recordid", recordIdByteBuf);
> ...
> context.write(keys, vbles);
> }
>
I finally got it working after finding the LongSerializer class source in
cassandra,
I see that the correct way to build a ByteBuffer key from a Long is
public ByteBuffer serialize(Long value)
{
return value == null ? ByteBufferUtil.EMPTY_BYTE_BUFFER :
ByteBufferUtil.bytes(value);
}
John
