[Hadoop-common-user] Read Objects from File

Hi,
I want to make a Generic BST in hadoop and for the same i require to read
"objects" , n at a time, from a file. Is there any input format that allows
me to do this? I tried to make the program only for Integers, but
nlinesinputformat is not working for me. I set the
"mapred.lines.input.format.linespermap" property to 10 lines, but i am
getting only 1 line at a time. Any ideas where am i going wrong?

Thanks,
Rahul