CODEWITHSUNDEEP
spring-batch
user1589089
user1589089

Reputation: 33

How to read multiple items in ItemReader

Following is my use case for spring batch.

  1. Reads the input from web service. Web service will return all records.

  2. Process the records.

  3. Write the processed records one by one.

I'm clear about step 2 and 3 but not able to figure out how to implement a reader which can read all the records in one go. How to pass the records one by one to item processor /writer? Should I be using tasklet instead of reader/writer?

Upvotes: 3

Views: 6619

Answers (1)

Cygnusx1
Cygnusx1

Reputation: 5409

What will your WebService Returns? A collection of object i guess!

Your ItemReader need to loop on this collection and remove items one-by-one then return null when they are all processed.

What @Kik was saying is the rest is handled by Spring batch based on your commit-interval. if you have a commit0interval of 10 for example, your reader will read 10 items, passed those 10 items to the ItemProc. then pass them again after to the writer.

Hope it clarify

EDIT: 1) In Spring Batch you have more than one option to do what you need.

Easy Option, create a custom MyWsItemReader that implements the ItemReader interface.

-Define a method init() in this class that will call your webService and put the results in a collection attribute of MyWsItemReader.

-Implements the method read() from the interface. (read carfully the contact in the doc - you must return null when you passed all the elements of the collection)

-Then, configure a stepListener around the step and implement the beforeStep() method to call the init() of your MyWsItemReader. You can autowire the reader in the listener to accomplish this.

Alternatively, your MyWsItemReader could also implements the InitializingBean. then you would have to implement the afterPropertySet() where you could call the ws and store the result in a private attribute of MyWsItemReader

regards

Upvotes: 8

Related Questions