Pentaho Input Text Set Field Null to Data Before

It is hard to explain this in word, so sorry if the title is mismatch.

So I have a file text like this:

Header A     Header B     Header C    Header D
Apple        Red          A           100
                          B           200
                          B           300
             Green        A           400
                          B           500
Eggplant     Purple       A           600
                          B           700
             White        a           800

And I want it to be read like this:

Header A     Header B     Header C    Header D
Apple        Red          A           100
Apple        Red          B           200
Apple        Red          B           300
Apple        Green        A           400
Apple        Green        B           500
Eggplant     Purple       A           600
Eggplant     Purple       B           700
Eggplant     White        a           800

But I confuse what transformation that I have to use.
So how to get this result in Pentaho? Or is there video tutorial I have to watch?
Thanks Before.

I have tried transformation "If Value is null" and "Filter Rows", but it doesn't seems the solution.

You can do it easily in Pentaho Data Integration with the text file input step. On the definition of fields just set the "Repeat" property to "Y".

If the field is null it will repeat the last non-null value and you get the results you're after.

Please try one of this solutions.
I don t use Postgresql but i m confident that this solutions will work also in Postgresql with small changes for exemple top 1 with limit 1 at the end.

If you have further questions or is something which you don t understand please ask me.
Do not use that update after the first solution if not the case.

with flo as
(select headera, headerb ,row_number ()over(order by (select null))as rn
 from prob1 ), 
flo1 as (
select *, last_value(headera)ignore nulls over(order by rn)as last,
last_value(headerb)ignore nulls over(order by rn)as last1
from flo)
update flo1
set headera= last , headerb=last1
from flo1
where headera is null or headerb is null
select * from prob1
drop table prob1

with flo as
 (select *, row_number ()over(order by (select null))as rn from prob2)
select headera, 
case when headera is null then(select top 1 headera from flo b 
where b.rn<a.rn and b.headera is not null order by b.rn desc) else headera end as headera1,
headerb,
case when headerb is null then(select top 1 headerb from flo c 
where c.rn<a.rn and c.headerb is not null  order by c.rn desc) else headerb end as headerb1
from flo a

with flo as
 (select *, row_number ()over(order by (select null))as rn from prob2),
flo1 as
 (select headera, count(headera)over(order by rn)as cate ,
headerb, count(headerb)over(order by rn)as cate1
from flo)
select headera, first_value(headera)over(partition by cate order by cate)as headeracor,
 headerb, first_value(headerb)over(partition by cate1 order by cate1)as headerbcor
from flo1

You can use the Modified JavaScript Value step.

You create two new columns, AltHeaderA and AltHeaderB (or you could rewrite HeaderA and HeaderB columns, but I like keeping the original values for clarity when debugging.

In the script, you just put:

if (HeaderA != null) {
	AltHeaderA = HeaderA;
}
if (HeaderB != null) {
	AltHeaderB = HeaderB;
}