What is equivalent to Informatica's Expression transformation in Kettle?

Hi,

I am new to kettle and evaluating it for one of prospect.

can anybody help me in finding transformation step in kettle equivalent to Informatica's Expression transformation(or abinitio's reformat)?

or

how can I do the following:

source data:

-----------

empno,empname,emp_salary

1,abc,7000

2,xyz,13000

3,xcv,22000

Target data:

-----------

empno,empname,emp_salary_grade

1,abc,C

2,xyz,B

3,xcv,A

logic for transformation is

if salary >=0 and <10000 then grade is C

if salary >=10000 and <20000 then grade is B

if salary >=20000 then grade is A

Please help me on this.

Thanks

Suneel