I need to execute a sequence of steps a specific number of times.. any pointers on what is the best way to do this in Spring Batch. I am able to implement executing a single step 'x' times. but my requirement is to execute a set of steps - based on a condition 'x' times.Any pointers will help.
Thanks
Lakshmi
You could put all steps in a job an start the whole job several times. There are different ways, how a job actually is launched in spring-batch. have a look at joboperator and launcher and then simply implement a loop around the launching of the job.
You can do this after the whole spring-context is initialized, so there will be no overhead concerning that. But you must by attention about the scope of your beans, especially the reader and writers.
Depending on your needs concerning failurehandling and restart, you also have pay attention how you manage the execution context of your job and steps.
You can simulate a loop with SB using a JobExecutionDecider:
Put it in front of all steps.
Store x in job execution context and check for x value into
decider: move to 'END' if x equals desidered value or increment it
and move to first step of set.
After last step move back to start (the decider).
Related
When I create a ParametersVariation simulation, the main model does not run. All I see is the default UI with iterations completed and replication. My end goal (as with most people) is to have a model go through a certain number of replications, but nothing is even running. There is limited documentation available on this. Please advise.
This is how Parameters Variation is intended to work. If you're running 1000 runs and multiple replications with parallel runs, how can you see what's happening in Main in each?
Typically, the best way to benefit from such an experiment is to track the results of each run using elements from the Analysis palette or even better to export results to Excel or similar.
To be able to collect data, you need to write your code in Java actions fields with root. to access elements in main (or top-level agent).
Check the example below, where after each run a variable from main is added to a dataset in the Parameters Variation experiment. At the end of 100 runs for example, the dataset will have 100 values of the main variable, with 1 value for each run.
I am trying to implement parallelization within talend. I have it working, but now I don't know how to connect the parallelization work to the next part. Usually, you would click on the previous block and select OnSubjobOk. That option doesn't appear. Is there another component that I need to add that I don't know about?
Under the basic settings of tParallelize you would find the option Wait For. This have two options -
end of first subjob: sequence the relevant subjob to be executed at
the end of the first subjob
end of all subjobs: sequence the relevant subjob to be executed at the end of all
subjobs.
So, all you have to do is connect your next part - your sub job with the tParallelize component by selecting the trigger - synchronize(wait for all). This would ensure once all the parallel subjobs/components are executed the sub job connected with synchronize(wait for all) will be executed.
My company has a couple of joblets that we put in new jobs to do things like initialization of variables, get system information from the database and sending out error / warning emails. The issue we are running into is that if we go ahead and start creating the components of a job and realize that we forgot to include these 3 joblets, we have to basically re-create the job to ensure that the joblets are added first so they run first.
Is there any way to force these joblets to run first and possibly also in a certain order before moving on to the contents of the job being created? Please let me know if there is any information you may need that I'm missing as I have only been using Talend for a few days. The rest of the team has not been using it too much longer than I have, so they do not have the answer I'm looking for either. Thanks in advance!
In Joblets you can use the components Trigger_Input and Trigger_Output as connection-points for on subjob OK triggers. So you can connect joblets and other components in a job with triggers. Thus enforcing execution order.
But you cannot get a on subjob OK trigger from a tPreJob. I am thinking on triggering from a tPreJob to a tWarn (on component OK) and then from tWarn to the joblet (on subjob OK).
I have a program, it loads a few tasks from a file prepared by user and start executing them according the scheduling shown in the file.
Example: taskFile.txt
Task1: run every hour
Task2: run every 2 seconds
...
TaskN: run every monday at 10:00
This first part is Ok, i solved by using ScheduledExecutorService and i am very satisfied. The tasks are load and run as they should.
Now, let's image that the user, by GUI (at runtime), decides that Task2 should run every minute, and he wants to remove Task3.
I cannot find any way to access one specific task in the pool, in order to remove/modify it.
So I cannot update tasks at runtime. When user changes a task, I can only modify the taskFile.txt and restart the application, in order to reload all tasks according the newly updated taskFile.txt.
Do you know any way to access a single task in order to modify/delete it?
Or even, a way to remove one given task, so i can insert a new one in the pool, with the modifications wanted by the user.
Thanks
This is not elegant, but works.
Let's suppose you need 10 threads, and sometimes you need to manage a specific thread.
Instead to have a pool with 10 thread, use 10 pools with one thread for each, keep them in your favourite data structure, and act on the pool_1 when you want to modify thread_1.
It's possible to remove the older Runnable from the pool and put a new one with the needed changes.
Otherways, anything put in the pool became anonymous and will be not directly manageable.
If somebody has a better solution...
I'm working on a requirement that defines a job/execution unit as a list of ordered steps which are themselves defined as a list of ordered substeps/phases. This job can be started beginning at any of the first-level steps, potentially ignoring the N-th first steps (and their substeps/phases).
What would be the best strategy for implementing this with spring batch ?
Cheers
A way to programmatically branching job execution (eg. skip step) is to use a JobExecutionDecider.