Passing data flow to a subjob

One Star

Passing data flow to a subjob

Hi,
I have a main job where i split according some conditions (trough a tmap) my flow into 2 flows and each of the flow should be processed by a subjob. How can i perform this action ? is it possible to pass a flow(not context) to a subjob ?
thank you for the answer
Best regards
One Star

Re: Passing data flow to a subjob

I just wanted to add that i don't want to dump data into temp file.  i want to it on the flow, using for example buffers ...
Employee

Re: Passing data flow to a subjob

Try the tHashInput and tHashOutput components. They are perfect for this. If you can't find them in your Studio, this website shows you how to find them.
One Star

Re: Passing data flow to a subjob

Thank you rhall,
I tough that thashXXX components must be used withing the same job.
My goal is to pass a flow from a parent job to a subjob, if possible with the thashXXX, please can you give me more details on how to use it in this case ?
B Regards
Seventeen Stars

Re: Passing data flow to a subjob

hi,
it's not a good solution for me but you can use context parameter (with componenet flowToIterate that put your data in globalMap)
Create a context group with the schema of your flow. Drag&drop it in child job & father job and pass each globalMap variable throught context parameter of the tRunJob.
tBuffer(output) is only from child job to father job.
a better solution is to store data in a file or mysql (myIsam engine) where I/O access are quick.
hope it helps
regards
laurent
One Star

Re: Passing data flow to a subjob

thank you Kzone,
But how do i get the values from the globalmap and translate them in a flow  in the CHILD JOB ?
Regards
Employee

Re: Passing data flow to a subjob

I think I misunderstood your question sofbar. I thought you were talking about passing between subjobs (ie the sections within a job that are grouped together). If you want to pass a dataset to a child job, then it may take a bit of Java coding....but it can be done.
What kzone described is a good solution for this. An example of how to do this would be to get your data into an ArrayList using a tJavaRow or tJavaFlex component. Create a context variable of type Object. If you don't program in Java, the Object class is the base class for all classes, therefore any object can be passed as an Object. Assign your ArrayList values to the Object context. Pass this context to your child job. Then in the child job, use a tJavaFlex to cast (change the type) the Object context to an ArrayList, then you can get your values from that. 
As kzone said, writing to another area would be better, but I can see why you might want to supply a small dataset like this at runtime without writing elsewhere.
One Star

Re: Passing data flow to a subjob

thank you for your reply rhall.
I am a beginner in java, can you please give the code for:
1) Assign your ArrayList values to the Object context
2) use a tJavaFlex to cast (change the type) the Object context to an ArrayList, then you can get your values from that.
thank you for your help
Regards
Employee

Re: Passing data flow to a subjob

Here are a couple of examples.....
1) After you have populated your ArrayList (http://java.about.com/od/javautil/a/Using-The-Arraylist.htm), simply save it to the context variable you have created as type Object....
context.myObjectContext = myArrayList;
2) I have an example of using an ArrayList with a tJavaFlex component here. The tutorial is about doing something else with Talend, but about 2/3 of the way down I have written a small bit on how the tJavaFlex is used in the example. This should give you an insight
To cast from an Object to an ArrayList you simply do the following.....
ArrayList myCastArrayList = (ArrayList)context.myObjectContext
Hope this helps
Regards
Richard
Seventeen Stars

Re: Passing data flow to a subjob

you can  also use the context params (no java to code Smiley Happy
see screenshoots

in the tRunJob I 've written each attriute coming from the flow (row1) in the definition of my context parameters.
in childJob I declare my context containing all my attribute & use a fixed flow component to (re)initialize my flow => logrow
Use tRowGenerator to generate data on the fly ...
result :
 

hope it helps
regards
laurent
One Star

Re: Passing data flow to a subjob

Thank you kzone for the tip !!
Regards
Employee

Re: Passing data flow to a subjob

That is another solution kzone, but that limits the child job to just processing one row at a time. Much simpler if that is all that is needed. But my assumption was that a complete data set is needed.
Seventeen Stars

Re: Passing data flow to a subjob

@rhall
aggree with you, and not a good solution. But it don't require any skills about java code.(@sofbar I am a beginner in java )
i'd like to Store on disk or database for that kind of stuff Smiley Happy
easy for unit test, debug & recovery error ... Smiley Wink
regards
laurent
One Star

Re: Passing data flow to a subjob

rhall,
this is the pattern of my jobs:
PARENT job: tfileinputdelimited===>tjavarow====>trunjob1
CHILD job : tjavaflex====> tfileoutpudelimited
in the tjavarow i am populating the arraylist.
in the tjavaflex i am populating columns of the output flow from the context param.
In the above case  i am transmitting to the child job row by row , right ? 
As you suggested i wanted the child job to process the whole set.
Best Regards
Employee

Re: Passing data flow to a subjob

Your job pattern is nearly there sofbar. However, you are likely passing the data like below to child job....
Row 1
1,2,3,4,5,6
Row 2
1,2,3,4,5,6
a,b,c,d,e,f
Row 3
1,2,3,4,5,6
a,b,c,d,e,f
1,2,3,4,5,6
.....
The first row will call the trunjob with the ArrayList with one row of data. The second row will call the trunjob with the ArrayList with the first and second row of data. The third row will call the trunjob with the ArrayList with the first, second and third rows of data, etc. To avoid this try out a pattern like below.....

PARENT Job: tFileInputDelimited===>tJavaRow===>tJava (Dummy component-does nothing)
                   ||
                 OnSubjobOK
                   ||
                   tJava(Dummy - does nothing) ----OnComponentOK-->tRunJob
CHILD Job: tJavaFlex ====>tFileOutputDelimited
This may need some tweaking, but hopefully you get the idea
Regards
Richard
One Star

Re: Passing data flow to a subjob

Hi Team,
Even i have similar requirement where i want to send continuous stream of dataset(id, json message string) from parent to child/sub job and i too am not proficient in java coding. So, need your help/guidance to implement talend job.
I want to either send (id,json message string) to subjob and read it in childjob and then extract table data per columns using tJSONExtract component?
OR
I want to extract json in parent job itself and send database columns (in the dataset) to child job?
Please help me here to achieve data flow from parent to child.
Thanks a lot for your time and help.
Rera
Four Stars

Re: Passing data flow to a subjob

Cant you refactor your "subjob" into a Joblet ?
A Joblet can have a flow input
Sixteen Stars

Re: Passing data flow to a subjob

I would steer well clear of Joblets. They really should have been removed from the toolset. They are hard to debug when they go wrong, often mix object names with objects on your job (causing several issues), force renaming of other objects and really don't provide any true "objectification" of your code. 
I would use KZone's solution that doesn't require Java.
One Star

Re: Passing data flow to a subjob

Thank you DJ, but i am using open studio which does not have an option to create a joblet
Thanks Richard, even i would prefer kzone solution as m no expert in Java but only concern with his appraoch is it will process one row at a time. I want to process multiple rows (dataset). How do i achieve that?