Spring batch: use before- and after-step methods within a CompositeItemWriter

Question

I need to read data from db and then generate an XLSX file and update data in db.

No issue for the reader part. For the writer part, I ended up creating a CompositeItemWriter, composed of a first Writer that generates the XLSX file and a second one that update data in db.

The problem: I need to intercept before- and after-step for the first writer in order to be able to properly write to the XLSX file in chunks. But, as soon as I compose both writers into a CompositeItemWriter, methods annotated with @BeforeStep et @AfterStep are not called.

Same issue when making the first writer implement StepExecutionListener.

Any idea why?

Here follows the CompositeItemWriter definition, the step and the writer:

public CompositeItemWriter<Adhesion> compositeItemWriter() {
  CompositeItemWriter writer = new CompositeItemWriter();
  writer.setDelegates(Arrays.asList(adhesionToXlsWriter,  adhesionToDbWriter));
  return writer;
}

@Bean
public Step xlsStep(ItemReader<Adhesion> adhesionFromDbReader) {
   return stepBuilderFactory.get(JOB_NAME + "-step")
      .<Adhesion, Adhesion>chunk(10)
      .reader(adhesionFromDbReader)
      .writer(compositeWriter())
      .build();
   }


@Component
public class AdhesionToXlsWriter implements ItemWriter<Adhesion> {

   @BeforeStep
   public void beforeStep(StepExecution stepExecution) {
      // !! never called !!
   }

   @Override
   public void write(List<? extends Adhesion> items) throws Exception {
      // generate XLSX content
   }

   @AfterStep
   public ExitStatus afterStep(StepExecution stepExecution) {
      // !! never called !!
   }
}

Answer 1

You need to register the XslWriter as listener to the step. Use the "listener" method of the stepBuilder.

If a writer, reader, processor is "hidden" behind a composite class, the spring framework will not recognize it as listener automatically. therefore you have to do it "manually".