Dynamic step creationin Spring Batch using custom parameter for decision making

Question

Perfect solution for dynamic step creationin Spring Batch. Just that I am not able to get parameters into this , which will decide what step need to be executed or how can pass steps Array ?

<pre>@Bean
public Job job() {
    Step[] stepsArray = // create your steps array or pass it as a parameter
    SimpleJobBuilder jobBuilder = jobBuilderFactory.get("mainCalculationJob")
            .incrementer(new RunIdIncrementer())
            .start(truncTableTaskletStep());
    for (Step step : stepsArray) {
        jobBuilder.next(step);
    }
    return jobBuilder.build();
}</pre>

Thanks

Answer 1

i am looking how to pass this step array as parameter and get in above function

Here is an example of how to pass the steps array as a parameter:

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.job.builder.SimpleJobBuilder;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableBatchProcessing
public class MyJobConfiguration {

    private final JobBuilderFactory jobBuilderFactory;
    private final StepBuilderFactory stepBuilderFactory;

    public MyJobConfiguration(JobBuilderFactory jobBuilderFactory, StepBuilderFactory stepBuilderFactory) {
        this.jobBuilderFactory = jobBuilderFactory;
        this.stepBuilderFactory = stepBuilderFactory;
    }

    public Step initialStep() {
        return stepBuilderFactory.get("initialStep")
                .tasklet((contribution, chunkContext) -> {
                    System.out.println("initial step");
                    return RepeatStatus.FINISHED;
                })
                .build();
    }
    
    @Bean
    public Step[] dynamicSteps() {
        // load steps sequence from db and create steps here
        Step step1 = stepBuilderFactory.get("step1")
                .tasklet((contribution, chunkContext) -> {
                    System.out.println("hello");
                    return RepeatStatus.FINISHED;
                })
                .build();
        Step step2 = stepBuilderFactory.get("step2")
                .tasklet((contribution, chunkContext) -> {
                    System.out.println("world");
                    return RepeatStatus.FINISHED;
                })
                .build();
        return new Step[]{step1, step2};
    }

    @Bean
    public Job job(Step[] dynamicSteps) {
        SimpleJobBuilder jobBuilder = jobBuilderFactory.get("job")
                .start(initialStep());
        for (Step step : dynamicSteps) {
            jobBuilder.next(step);
        }
        return jobBuilder.build();
    }

    public static void main(String[] args) throws Exception {
        ApplicationContext context = new AnnotationConfigApplicationContext(MyJobConfiguration.class);
        JobLauncher jobLauncher = context.getBean(JobLauncher.class);
        Job job = context.getBean(Job.class);
        jobLauncher.run(job, new JobParameters());
    }

}

Nothing related to Spring Batch here, this is Spring dependency injection: passing an array of beans of type Step as a parameter to a another bean definition method (of type Job).