Try passing the variables into the mapper through the JobConf.set
and .get methods.
On Dec 4, 2008, at 3:45 AM, abhinit wrote:
Hi,
I am implementing basic selection/projection using mapreduce on an
HBase
table.
I have an outer class SelectProject which implements the tool
interface and
my mapper class,
SelectProjectOperator extends TableMap.
In my run method, I am parsing the command line argument for things
like
column names
and predicate condition(say key = 10000 etc.) and I have to use
these values
inside the map
method of my mapper class. All the variables to be used in the map
function
for selection/projection
are static variables of the enclosing outer class(SelectProject). I
et these
variables in run method
after parsing the comman-line arguments.
However, in the map method I get a NullPointerException because non-
of those
static member variables
are created. I understand this is not exactlt an HBase related issue
and has
something to do with java inner classes.
But I thought this can be a very common case in mapreduce programming
(passing a condition variable from the
outer class to enclosed mapper class' map method).
Thanks a lot for help.
-Abhinit
--
Abhinit Kumar
MSE, Computer & Information Science
Class of 2009
University of Pennsylvania
1-215-796-5136
