Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Plain View
HDFS, mail # user - Context Object in Map Reduce


+
Tanniru Govardhan 2013-07-26, 13:37
+
manish dunani 2013-07-26, 14:33
Copy link to this message
-
Re: Context Object in Map Reduce
manish dunani 2013-07-26, 14:56
If u r using OutputCollector,Reporter then no need to use Context..Context
works same as OutputCollector and Reporter.

That is used to collect mapper's <key ,value> pair.

On Fri, Jul 26, 2013 at 8:03 PM, manish dunani <[EMAIL PROTECTED]> wrote:

> Can u please elaborate what is the code and what is error.??
>
> Then it will be much better to give the answer.
>
> Regards Manish Dunani..
>
>
> On Fri, Jul 26, 2013 at 7:07 PM, Tanniru Govardhan <
> [EMAIL PROTECTED]> wrote:
>
>> Hi everyone,
>> I am trying to pass a string variable from Driver class to Mapper class.
>> I came to know that i need to use context variable for this purpose.
>> But the Mapper method i have used has a signature without context object.
>> It is not allowing to change the method signature.(reporting syntax
>> error)
>> Can anyone please suggest me what can I do regarding this?
>> I am very new to Map Reduce Programming.
>>
>> Here is the code:
>>
>> class Map<V> extends MapReduceBase implements Mapper<LongWritable, Text,
>> Text, IntWritable>
>> {
>>     String myfilename;
>>   private Text word = new Text();
>>   private IntWritable var = new IntWritable();
>>
>>   public void map(LongWritable key, Text value, *Context context,*OutputCollector<Text, IntWritable> output, Reporter reporter)
>> *//here is the error *
>>  throws IOException
>> {
>>          Configuration conf = context.getConfiguration();
>>              myfilename = conf.get("filename");
>>              -- - - -- - -- -
>>         }
>>  public  void compute() throws Exception
>>   {
>>   Configuration config = new Configuration();
>>       config.set("filename", "Syn-100n-8t-2l-2k.vars");
>>
>>     JobConf conf = new JobConf(Hadoop_GNTS.class);
>>     -- - - - -- - -
>> }
>>
>> Thanks
>>
>>
>
>
> --
> MANISH DUNANI
> -THANX
> +91 9426881954,+91 8460656443
> [EMAIL PROTECTED]
>

--
MANISH DUNANI
-THANX
+91 9426881954,+91 8460656443
[EMAIL PROTECTED]
+
Tanniru Govardhan 2013-07-26, 15:36