Thanks for ur reply Robert Dyer.

Thanks for spending ur valuabl= e time for clearing my doubts.

<= /div>

= I need to pass some other values too

Reducer

------------

public =A0= class Reduce extends MapReduceBase

implements Reducer<Text, IntWritable= , Text, IntWritable> {

static int cnt =3D0;

ArrayList<String> ar =3D new ArrayList<String>();

<= span class=3D"" style=3D"white-space:pre"> String data =3D null;

public void reduce(Text key, Iterat= or<IntWritable> values,

= OutputCollector<Text, IntWritable> output,

Reporter reporter) throws IOExcep= tion {

System.out.prin= tln("In reducer");

int sum =3D 0;

String line =3D key.toString();

<= span class=3D"" style=3D"white-space:pre"> StringTokenizer itr =3D = new StringTokenizer(line);

while (values.hasNext()) {<= /div>

sum +=3D values.next().get()= ;

}

output.collect(key, new IntWritable(sum));

String data =3D key+" &= quot;+sum;

ar.add(data);

=A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0writeToFile(ar);

ar.add("\n");

int index=3DInteger.parseI= nt(itr.nextToken());

String value=3Ditr.nextToken();

<= span class=3D"" style=3D"white-space:pre"> String classLabel=3Ditr.= nextToken();

int count=3Dsum;

}

publ= ic static void writeToFile(ArrayList<String> =A0text) {

System.out.println("In reduce= write to file ");

try {

cnt++;

C= 45 id=3Dnew C45();

System.out.println("count &q= uot;+cnt);

Path input =3D new P= ath("C45/intermediate"+id.current_index+".txt");=

Configuration conf =3D new Configuration();

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 FileSystem fs =3D FileSyst= em.get(conf);

Buf= feredWriter bw =3D new BufferedWriter(

new OutputStreamWriter(fs.creat= e(input, true)));

System.out.println("Text fro= m Reducer: "+ "C45/intermediate"+id.current_index+".txt= "+ text);

System.out.println("file exi= sts:C45/intermediate"+id.current_index+".txt"+fs.exists(inpu= t));

for(String str: text) {

bw.write(str);

}

bw.newLine();

<= div class=3D"gmail_default"> bw.close();

} catch (Exception e) {

System.out.println("File i= s not creating in reduce");

}

Driver

----= ----

GainRa= tio =A0gainObj =3D new GainRatio();<= /div>

gainObj.getcount();

<= font face=3D"arial, sans-serif">

GainRatio<= /span>

--------------=

public void getcount()

{=A0

System.out.println("In gainratio --- getcount ");

C45 id=3Dnew C45();

FileInputStream fs= tream;

try {<= /div>

Configuration config =3D new Configuration();

FileSystem dfs = =3D FileSystem.get(config);

Path path =3D new Path("C45/intermediate"+id.= current_index+".txt");

System.out.= println("file exists:C45/intermediate"+id.current_index+".tx= t"+dfs.exists(path));

System.out.println(path);

BufferedReader br= =3Dnew BufferedReader(new InputStreamReader(dfs.open(path)));

String line;

StringTokenizer itr;

while ((lin= e =3D br.readLine()) !=3D null) =A0 {

System.out.println("In gain Ratio : &q= uot;+line);

itr=3D new Strin= gTokenizer(line);

= count[linenumber][0]=3Ditr.nextToken();

count[linenumber][1]=3Ditr.nextToken();=

count[linenumber= ][2]=3Ditr.nextToken();

count[linenumber][3]=3Ditr.nextToken();

int i=3Dlinenumber;

linenumber++;

}

System.out.println(&= quot;outsidec while");

count[linenumber]= [0]=3Dnull;

= count[linenumber][1]=3Dnull;

count[linenumber][2]=3Dnull;

count[linenumber]= [3]=3Dnull;

= br.close();

= emptyfile(id.current_index);

} c= atch (Exception e) {

e.printStackTrace();

}

Here from reducer many files are = created

eg: intermediate0.txt

=A0 =A0 =A0.....upto inte= rmediate7.txt according to my input dataset.

But here only intermediate0.txt is created all other cr= eation of file get failed.

Is that the same reason you explained = before.

For this also should i go for couters?

On Wed, Dec 18, 2013 at 11:09 PM, Robert D= yer <psybers@gmail.com> wrote:

Generally speaking, static = fields are not useful in Hadoop.

The issue you are seein= g is that the reducer is running in a separate VM (possibly on a different = node!) and thus the static value you are reading inside of Mid is actually = a separate instantiation of that class and field.

If you have an integer you need to set and read from th= e driver/mid, you can use a counter. =A0E.g.:

http://www.philippeadjiman= .com/blog/2010/01/07/hadoop-tutorial-series-issue-3-counters-in-action/=

- Robert

On Wed, Dec 18, 2013 at 4:0= 2 AM, unmesha sreeveni <unmeshabiju@gmail.com> wrote:
Can any one pls suggest a good way=A0
My scenario:
i hav
1.Driver class
2.Mapper class
3.reducer class
4.Mid cl= ass
After compl= eting mapper it goes to reduce. From reducer it will be going to Driver and= from driver to Mid class

so i need to get a data from reducer class to Mi= d class
=A0So for that i declared a static variable in reduce and tried to access t= hat variable in Mid class.But while executing i am only getting the 0 value= . How to overcome this.

Reducer.java
--------------------

public =A0class Reduce extends MapR= educeBase
implements Re= ducer<Text, IntWritable, Text, IntWritable> {

int ig;
public vo= id reduce(Text key, Iterator<IntWritable> values,

OutputCollector<Text, IntWritable> output,
Reporter reporter) throws IOException {

=A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0ig =3D 9;
}
}
Driver.java
= =A0 =A0 =A0 =A0gainObj.getcount();

= Mid.java
public class Mid{

public void getcount(String ar= gs) throws IOException
{=A0

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0//WANT TO GET THE IG VALUE IE &= quot;9" HERE So i did like this
=A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 Reduce r =3D new Reduce();
System.out.println("red= "+ r.ig);
}
}
But my result is "0&= quot;. Not 9.

How to solve this?

--
Thanks & Regards

Unmesha Sreeveni U.B
Junior Developer

Thanks & Regards

Unmesha Sreeveni U.B

Junior Developer

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