For both 1 and 2, if your metadata is a Writable, you can simply reuse its readFields() and write() methods to serialize it into and out of the data output/input streams.
For instance, assume dos is out, and dis is in, and obj1 (K) and obj2 (V) are my writables, then I do: To write K and V: obj1.write(dos); obj2.write(dos); To read K and V in proper order (order is important when deserializing), reconstruct your writable objects and read them in: obj1.readFields(dis); obj2.readFields(dis); Does this not work for you? On Tue, Jul 3, 2012 at 6:37 AM, Dare <dayakar.bit...@gmail.com> wrote: > Hi Hadoop Team, > > I have been working with the TFiles in Hadoop. I got a few questions > regarding Named Meta Blocks. > > 1) Using TFile.Writer one can append a <K,V> pair. But, if I prepare a Meta > Block, then it returns a DataOutputStream which allows to write in byte[], > since my <K,V> pairs are serialized objects. > Is this the same way or is there something I am missing. Because, out of > my understanding, if I write it as a <K,V> pair, the key indexes will be > prepared at the tail of the TFile. > But, when I write it as a just byte[], i am not sure if the indexes are > formed. > > 2) While reading, is there a way to read <K,V> entry using the > DataInputStream got from the getMetaBlock(). > > Thanks > DaRe -- Harsh J
