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Hadoop, mail # user - The method setMapperClass(Class<? extends Mapper>) in the type Job is not applicable for the arguments


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Ronan Lehane 2013-02-09, 17:57
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Harsh J 2013-02-09, 18:09
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Ronan Lehane 2013-02-09, 18:17
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Re: The method setMapperClass(Class<? extends Mapper>) in the type Job is not applicable for the arguments
Harsh J 2013-02-09, 18:35
Your import line of Mapper has the issue. It is imported as below,
which can probably be removed as it is unnecessary:

import org.apache.hadoop.mapreduce.Mapper.Context;

But you also would need the line below for the actual class to get found:

import org.apache.hadoop.mapreduce.Mapper;

Adding that line to your list of imports should help resolve it.

I recall some IDEs being odd about these things sometimes, and not
reporting the real error correctly. Were you using one? Eclipse?

On Sat, Feb 9, 2013 at 11:47 PM, Ronan Lehane <[EMAIL PROTECTED]> wrote:
> Hi Harsh,
>
> Thanks for getting back so quickly.
>
> The full source code is attached as there's nothing sensitive in it.
> Coding wouldn't be my strong point so apologies in advance if it looks a
> mess.
>
> Thanks
>
>
> On Sat, Feb 9, 2013 at 6:09 PM, Harsh J <[EMAIL PROTECTED]> wrote:
>>
>> Whatever "csatAnalysis.MapClass" the compiler picked up, it appears to
>> not be extending the org.apache.hadoop.mapreduce.Mapper class. From
>> your snippets it appears that you have it all defined properly though.
>> A common issue here has also been that people accidentally import the
>> wrong API (mapred.*) but that doesn't seem to be the case either.
>>
>> Can you post your full compilable source somewhere? Remove any logic
>> you don't want to share - we'd mostly be interested in the framework
>> definition parts alone.
>>
>> On Sat, Feb 9, 2013 at 11:27 PM, Ronan Lehane <[EMAIL PROTECTED]>
>> wrote:
>> > Hi All,
>> >
>> > I hope this is the right forum for this type of question so my apologies
>> > if
>> > not.
>> >
>> > I'm looking to write a map reduce program which is giving me the
>> > following
>> > compilation error:
>> > The method setMapperClass(Class<? extends Mapper>) in the type Job is
>> > not
>> > applicable for the arguments (Class<csatAnalysis.MapClass>)
>> >
>> > The components involved are:
>> >
>> > 1. Setting the Mapper
>> >         //Set the Mapper for the job. Calls MapClass.class
>> >         job.setMapperClass(MapClass.class);
>> >
>> > 2. Setting the inputFormat to TextInputFormat
>> >         //An InputFormat for plain text files. Files are broken into
>> > lines.
>> >         //Either linefeed or carriage-return are used to signal end of
>> > line.
>> >         //Keys are the position in the file, and values are the line of
>> > text..
>> >         job.setInputFormatClass(TextInputFormat.class);
>> >
>> > 3. Taking the data into the mapper and processing it
>> >     public static class MapClass extends Mapper<LongWritable, Text,
>> > Text,
>> > VectorWritable> {
>> >         public void map (LongWritable key, Text value,Context context)
>> > throws IOException, InterruptedException {
>> >
>> > Would anyone have any clues as to what would be wrong with the
>> > arguements
>> > being passed to the Mapper?
>> >
>> > Any help would be appreciated,
>> >
>> > Thanks.
>>
>>
>>
>> --
>> Harsh J
>
>

--
Harsh J
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Ronan Lehane 2013-02-09, 18:40
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Ronan Lehane 2013-02-09, 18:44