springbatch partition vs parallel

I need your help.
Here's the story that I want to program.

1. call rest api each 5 targets(stores)
   to get the total number of orderId and orderIds and save them to the repository.

2. select total number of orderId and orderIds dividely
   and call another rest api each 5 targets(stores) to get order list
   using as parameter total number of orderId and orderIdsand save to the repository.

I want to know how should I do in the spring batch like partitioning, parallel steps...
Can you help me to organize the process of how to make it?

I am learning about partitioning and parallel steps

• Define a Job with two main steps:
  Step 1: Fetch order data from the REST APIs.
  Step 2: Call another REST API to get the order list and save it to the repository.

• Implement partitioning for each step to process multiple stores in parallel.

Define the Job:

@Configuration
@EnableBatchProcessing
public class OrderProcessingJobConfig {
@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;
// Define your reader, processor, and writer beans
@Bean
public Job orderProcessingJob() {
return jobBuilderFactory.get("orderProcessingJob")
.start(fetchOrderDataStep())
.next(getOrderListStep())
.build();
}
@Bean
public Step fetchOrderDataStep() {
// Step 1 configuration goes here
}
@Bean
public Step getOrderListStep() {
// Step 2 configuration goes here
}
}

Implement partitioning for each step:

@Bean
public Step fetchOrderDataStep() {
return stepBuilderFactory.get("fetchOrderDataStep")
.partitioner("fetchOrderDataStep", partitioner())
.step(fetchOrderDataStepSlave())
.gridSize(5) // Number of parallel threads
.taskExecutor(taskExecutor())
.build();
}
@Bean
public Partitioner partitioner() {
return new StorePartitioner(); // A custom partitioner implementation
}
@Bean
public Step fetchOrderDataStepSlave() {
return stepBuilderFactory.get("fetchOrderDataStepSlave")
.<InputType, OutputType>chunk(5)
.reader(reader(null))
.processor(processor())
.writer(writer())
.build();
}
@Bean
@StepScope
public ItemReader<InputType> reader(@Value("#{stepExecutionContext['targetStore']}") String targetStore) {
// Implement your REST API reader
}
@Bean
public TaskExecutor taskExecutor() {
return new SimpleAsyncTaskExecutor();
}

Call another REST API to get the order list and save it to the repository.

@Bean
public Step getOrderListStep() {
return stepBuilderFactory.get("getOrderListStep")
.partitioner("getOrderListStep", partitioner())
.step(getOrderListStepSlave())
.gridSize(5) // Number of parallel threads
.taskExecutor(taskExecutor())
.build();
}
@Bean
public Step getOrderListStepSlave() {
return stepBuilderFactory.get("getOrderListStepSlave")
.<InputType, OutputType>chunk(5)
.reader(orderListReader(null))
.processor(orderListProcessor())
.writer(orderListWriter())
.build();
}
@Bean
@StepScope
public ItemReader<InputType> orderListReader(@Value("#{stepExecutionContext['targetStore']}") String targetStore) {
// Implement your REST API reader for the order list
}

for the new requirement as per the comment

Define a Job with two main steps (as before):
a. Step 1: Fetch order data from the REST APIs.
b. Step 2: Call another REST API to get the order list and save it to the repository.

Use a Flow to define parallel steps for each target store.

@Configuration
@EnableBatchProcessing
public class OrderProcessingJobConfig {
@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;
// Define your reader, processor, and writer beans
@Bean
public Job orderProcessingJob() {
return jobBuilderFactory.get("orderProcessingJob")
.start(fetchOrderDataFlow())
.split(taskExecutor()) // Add this line to split the flow
.add(getOrderListFlow())
.end()
.build();
}
@Bean
public Flow fetchOrderDataFlow() {
FlowBuilder<SimpleFlow> flowBuilder = new FlowBuilder<>("fetchOrderDataFlow");
// Add all target store steps in parallel
flowBuilder.split(taskExecutor())
.add(fetchOrderDataStep1(), fetchOrderDataStep2(), fetchOrderDataStep3(), fetchOrderDataStep4(), fetchOrderDataStep5());
return flowBuilder.build();
}
@Bean
public Flow getOrderListFlow() {
FlowBuilder<SimpleFlow> flowBuilder = new FlowBuilder<>("getOrderListFlow");
// Add all target store steps in parallel
flowBuilder.split(taskExecutor())
.add(getOrderListStep1(), getOrderListStep2(), getOrderListStep3(), getOrderListStep4(), getOrderListStep5());
return flowBuilder.build();
}
@Bean
public TaskExecutor taskExecutor() {
return new SimpleAsyncTaskExecutor();
}
}

2: Define separate step beans for each target store:

// Step 1: Fetch order data from the REST APIs
@Bean
public Step fetchOrderDataStep1() {
return createFetchOrderDataStep("fetchOrderDataStep1", "store1");
}
@Bean
public Step fetchOrderDataStep2() {
return createFetchOrderDataStep("fetchOrderDataStep2", "store2");
}
@Bean
public Step fetchOrderDataStep3() {
return createFetchOrderDataStep("fetchOrderDataStep3", "store3");
}
@Bean
public Step fetchOrderDataStep4() {
return createFetchOrderDataStep("fetchOrderDataStep4", "store4");
}
@Bean
public Step fetchOrderDataStep5() {
return createFetchOrderDataStep("fetchOrderDataStep5", "store5");
}
private Step createFetchOrderDataStep(String stepName, String targetStore) {
return stepBuilderFactory.get(stepName)
.<InputType, OutputType>chunk(5)
.reader(reader(targetStore))
.processor(processor())
.writer(writer())
.build();
}

// Step 2: Call another REST API to get the order list and save it to the repository

@Bean
public Step getOrderListStep1() {
return createGetOrderListStep("getOrderListStep1", "store1");
}
@Bean
public Step getOrderListStep2() {
return createGetOrderListStep("getOrderListStep2", "store2");
}
@Bean
public Step getOrderListStep3() {
return createGetOrderListStep("getOrderListStep3", "store3");
}
@Bean
public Step getOrderListStep4() {
return createGetOrderListStep("getOrderListStep4", "store4");
}
@Bean
public Step getOrderListStep5() {
return createGetOrderListStep("getOrderListStep5", "store5");
}
private Step createGetOrderListStep(String stepName, String targetStore) {
return stepBuilderFactory.get(stepName)
.<InputType, OutputType>chunk(5)
.reader(orderListReader(targetStore))
.processor(orderListProcessor())
.writer(orderListWriter())
.build();
}