Yes, I find the MapWritable in org.apache.hadoop.io, it's very useful. Thank you very much!
On Sat, Dec 1, 2012 at 4:38 PM, Thomas Jungblut <[email protected]>wrote: > Like I told you, the aggregator works through the message type of your > vertex. This must be Writable, so if you find a HashMap that is Writable > (maybe you have to write your own) and this is your message type in your > algorithm. Then this will work automatically if you implement your > reduction operations correctly in the aggregator. > > > > 2012/12/1 lee fei <[email protected]> > > > hi Thomas, > > I want to use an aggregator to store an HashMap, and in every > superstep, > > different vertexes may put or remove an element<key, value> to the > HashMap, > > and I am wondering at the sync phase,if the master will automatic sync > the > > HashMap? > > > > Just like this: > > > > superstep n: HashMap: 1,2,3,4,5,6 > > > > task1 modified the aggregator: > > HashMap(1): 3,4,5,6(task1 remove 1,2) > > > > task2 modified the aggregator: > > HashMap(2): 1,2,3,4,5,6,7,8(task2 add 7,8) > > .... > > and after the sync phase also in next superstep: > > the HashMap become: 3,4,5,6,7,8 > > > > Did I got it? the namenode will automatic do this? > > > > > > On Thu, Nov 29, 2012 at 8:52 PM, lee fei <[email protected]> wrote: > > > > > Thanks for you quick reply:) > > > > > > Best wishes for you:D > > > > > > > > > On Thu, Nov 29, 2012 at 8:01 PM, Thomas Jungblut < > > > [email protected]> wrote: > > > > > >> Yes, if they are Writable and are part of your vertex message or value > > >> type. > > >> You may want to have a look at MapWritable or other serializable > > >> collections in the org.apache.hadoop.io package. > > >> > > >> 2012/11/29 lee fei <[email protected]> > > >> > > >> > Hi, > > >> > > > >> > I am a newbie to hama,Can Aggregator in graph package store an > > >> Arraylist > > >> > or a HashMap for some special usages? > > >> > > > >> > Thank you for you attention~ > > >> > > > >> > > > > > > > > >
