There has to be an implicit contract between the producer and consumer. The K, V pairs don't _need_ to match but generally _should_. If producer sends with <PK, PV> the consumer may receive <CK, CV> as long as it knows how to convert those raw bytes to <CK, CV>. In the example if CK == byte[] and CV == byte[] it is effectively a no-op conversion.
On Thu, Feb 05, 2015 at 12:11:03PM -0800, Yang wrote: > in the example > https://cwiki.apache.org/confluence/display/KAFKA/0.8.0+Producer+Example > > we use a String,String for <K,V> > > in the same set of example > https://cwiki.apache.org/confluence/display/KAFKA/Consumer+Group+Example > > on the consumer side we use byte[], byte[] for K,V > ConsumerIterator<byte[], byte[]> it = m_stream.iterator(); > > > > we tested in our own code that the above producer-consumer pair does work. > > > so the K,V types on the 2 sides do NOT need to match? if we argue that > "everything has to come down to byte[], then maybe we don't need the > generics types on the consumer side? in other words, how do we determine > the K,V types on consumer side? > > thanks > Yang
