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Posted to common-user@hadoop.apache.org by Prabhu Hari Dhanapal <dr...@gmail.com> on 2010/02/12 02:10:37 UTC
Identity Reducer
Hi all,
I m trying to Write a program that performs some simple Datamining on a
certain DataSet. I was told that an Identity Reducer should be written.
public class Reduce extends MapReduceBase implements Reducer {
public void reduce(Text key, Iterator<IntWritable>
values,OutputCollector<Text, IntWritable> output,
Reporter reporter) throws IOException {
===>
It shows me the following exception ..
"The type Reducer cannot be a superinterface of Reduce; a superinterface
must be an interface "
Can I have some pointers on solving this?
--
Hari
Re: Identity Reducer
Posted by Prabhu Hari Dhanapal <dr...@gmail.com>.
hey aaron,
thanks :) I had just messed up with the class nesting ! It works now !
On Thu, Feb 11, 2010 at 11:55 PM, Aaron Kimball <aa...@cloudera.com> wrote:
> Can you post the entire exception with its accompanying stack trace?
> - Aaron
>
> On Thu, Feb 11, 2010 at 5:26 PM, Prabhu Hari Dhanapal <
> dragonzsnake@gmail.com> wrote:
>
> > @ Jeff
> > I seem to have used the Mapper you are pointing to ...
> >
> >
> > import org.apache.hadoop.mapred.MapReduceBase;
> > import org.apache.hadoop.mapred.Mapper;
> >
> > Will that affect the Reducer in any sense?
> >
> >
> > On Thu, Feb 11, 2010 at 8:19 PM, Jeff Zhang <zj...@gmail.com> wrote:
> >
> > > I guess you are using org.apache.hadoop.mapreduce.Mapper which is a
> class
> > > for hadoop new API. you can use the org.apache.hadoop.mapred.Mapper
> which
> > > is
> > > for old API
> > >
> > >
> > >
> > > On Thu, Feb 11, 2010 at 5:10 PM, Prabhu Hari Dhanapal <
> > > dragonzsnake@gmail.com> wrote:
> > >
> > > > Hi all,
> > > >
> > > > I m trying to Write a program that performs some simple Datamining on
> a
> > > > certain DataSet. I was told that an Identity Reducer should be
> written.
> > > >
> > > > public class Reduce extends MapReduceBase implements Reducer {
> > > >
> > > > public void reduce(Text key, Iterator<IntWritable>
> > > > values,OutputCollector<Text, IntWritable> output,
> > > > Reporter reporter) throws IOException {
> > > >
> > > > ===>
> > > > It shows me the following exception ..
> > > >
> > > > "The type Reducer cannot be a superinterface of Reduce; a
> > superinterface
> > > > must be an interface "
> > > > Can I have some pointers on solving this?
> > > >
> > > >
> > > > --
> > > > Hari
> > > >
> > >
> > >
> > >
> > > --
> > > Best Regards
> > >
> > > Jeff Zhang
> > >
> >
> >
> >
> > --
> > Hari
> >
>
--
Hari
Re: Identity Reducer
Posted by Aaron Kimball <aa...@cloudera.com>.
Can you post the entire exception with its accompanying stack trace?
- Aaron
On Thu, Feb 11, 2010 at 5:26 PM, Prabhu Hari Dhanapal <
dragonzsnake@gmail.com> wrote:
> @ Jeff
> I seem to have used the Mapper you are pointing to ...
>
>
> import org.apache.hadoop.mapred.MapReduceBase;
> import org.apache.hadoop.mapred.Mapper;
>
> Will that affect the Reducer in any sense?
>
>
> On Thu, Feb 11, 2010 at 8:19 PM, Jeff Zhang <zj...@gmail.com> wrote:
>
> > I guess you are using org.apache.hadoop.mapreduce.Mapper which is a class
> > for hadoop new API. you can use the org.apache.hadoop.mapred.Mapper which
> > is
> > for old API
> >
> >
> >
> > On Thu, Feb 11, 2010 at 5:10 PM, Prabhu Hari Dhanapal <
> > dragonzsnake@gmail.com> wrote:
> >
> > > Hi all,
> > >
> > > I m trying to Write a program that performs some simple Datamining on a
> > > certain DataSet. I was told that an Identity Reducer should be written.
> > >
> > > public class Reduce extends MapReduceBase implements Reducer {
> > >
> > > public void reduce(Text key, Iterator<IntWritable>
> > > values,OutputCollector<Text, IntWritable> output,
> > > Reporter reporter) throws IOException {
> > >
> > > ===>
> > > It shows me the following exception ..
> > >
> > > "The type Reducer cannot be a superinterface of Reduce; a
> superinterface
> > > must be an interface "
> > > Can I have some pointers on solving this?
> > >
> > >
> > > --
> > > Hari
> > >
> >
> >
> >
> > --
> > Best Regards
> >
> > Jeff Zhang
> >
>
>
>
> --
> Hari
>
Re: Identity Reducer
Posted by Prabhu Hari Dhanapal <dr...@gmail.com>.
@ Jeff
I seem to have used the Mapper you are pointing to ...
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
Will that affect the Reducer in any sense?
On Thu, Feb 11, 2010 at 8:19 PM, Jeff Zhang <zj...@gmail.com> wrote:
> I guess you are using org.apache.hadoop.mapreduce.Mapper which is a class
> for hadoop new API. you can use the org.apache.hadoop.mapred.Mapper which
> is
> for old API
>
>
>
> On Thu, Feb 11, 2010 at 5:10 PM, Prabhu Hari Dhanapal <
> dragonzsnake@gmail.com> wrote:
>
> > Hi all,
> >
> > I m trying to Write a program that performs some simple Datamining on a
> > certain DataSet. I was told that an Identity Reducer should be written.
> >
> > public class Reduce extends MapReduceBase implements Reducer {
> >
> > public void reduce(Text key, Iterator<IntWritable>
> > values,OutputCollector<Text, IntWritable> output,
> > Reporter reporter) throws IOException {
> >
> > ===>
> > It shows me the following exception ..
> >
> > "The type Reducer cannot be a superinterface of Reduce; a superinterface
> > must be an interface "
> > Can I have some pointers on solving this?
> >
> >
> > --
> > Hari
> >
>
>
>
> --
> Best Regards
>
> Jeff Zhang
>
--
Hari
Re: Identity Reducer
Posted by Jeff Zhang <zj...@gmail.com>.
I guess you are using org.apache.hadoop.mapreduce.Mapper which is a class
for hadoop new API. you can use the org.apache.hadoop.mapred.Mapper which is
for old API
On Thu, Feb 11, 2010 at 5:10 PM, Prabhu Hari Dhanapal <
dragonzsnake@gmail.com> wrote:
> Hi all,
>
> I m trying to Write a program that performs some simple Datamining on a
> certain DataSet. I was told that an Identity Reducer should be written.
>
> public class Reduce extends MapReduceBase implements Reducer {
>
> public void reduce(Text key, Iterator<IntWritable>
> values,OutputCollector<Text, IntWritable> output,
> Reporter reporter) throws IOException {
>
> ===>
> It shows me the following exception ..
>
> "The type Reducer cannot be a superinterface of Reduce; a superinterface
> must be an interface "
> Can I have some pointers on solving this?
>
>
> --
> Hari
>
--
Best Regards
Jeff Zhang