writing to HDFS with a given username

[Philip Ogren]

When I call rdd.saveAsTextFile("hdfs://...") it uses my username to 
write to the HDFS drive.  If I try to write to an HDFS directory that I 
do not have permissions to, then I get an error like this:

Permission denied: user=me, access=WRITE, 
inode="/user/you/":you:us:drwxr-xr-x

I can obviously get around this by changing the permissions on the 
directory /user/you.  However, is it possible to call rdd.saveAsText 
with an alternate username and password?

Thanks,
Philip