Batch

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>at.aydin.academy</groupId>
        <artifactId>06batch-pair</artifactId>
        <version>1.0.0</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <artifactId>batch-modern</artifactId>
    <packaging>jar</packaging>
    <name>Batch Modern (Spring Batch)</name>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-batch</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.batch</groupId>
            <artifactId>spring-batch-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

package at.aydin.lab.batch.modern;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class BatchModernApplication {
    public static void main(String[] args) {
        SpringApplication.run(BatchModernApplication.class, args);
    }
}

spring.datasource.url=jdbc:h2:mem:batchmodern;DB_CLOSE_DELAY=-1
spring.sql.init.mode=always
spring.batch.jdbc.initialize-schema=always

package at.aydin.lab.batch.modern;

import java.math.BigDecimal;

public record OrderRow(long id, String customer, BigDecimal amount) {
}

id,customer,amount
2001,Delta GmbH,320.50
2002,Epsilon AG,99.90
2003,Zeta KG,450.00

package at.aydin.lab.batch.modern;

import javax.sql.DataSource;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.job.builder.JobBuilder;
import org.springframework.batch.core.repository.JobRepository;
import org.springframework.batch.core.step.builder.StepBuilder;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.database.JdbcBatchItemWriter;
import org.springframework.batch.item.database.builder.JdbcBatchItemWriterBuilder;
import org.springframework.batch.item.file.FlatFileItemReader;
import org.springframework.batch.item.file.builder.FlatFileItemReaderBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.transaction.PlatformTransactionManager;

@Configuration
// Design Pattern: Pipeline
// Zweck: Reader, Processor und Writer sind austauschbare, getrennt testbare Batch-Stufen.
public class BatchConfiguration {
    @Bean
    FlatFileItemReader<OrderRow> orderReader() {
        return new FlatFileItemReaderBuilder<OrderRow>()
                .name("orderReader")
                .resource(new ClassPathResource("sample-orders.csv"))
                .linesToSkip(1)
                .delimited()
                .names("id", "customer", "amount")
                .fieldSetMapper(fieldSet -> new OrderRow(
                        fieldSet.readLong("id"),
                        fieldSet.readString("customer"),
                        fieldSet.readBigDecimal("amount")))
                .build();
    }

    @Bean
    ItemProcessor<OrderRow, OrderRow> positiveAmountProcessor() {
        return item -> item.amount().signum() > 0 ? item : null;
    }

    @Bean
    JdbcBatchItemWriter<OrderRow> orderWriter(DataSource dataSource) {
        return new JdbcBatchItemWriterBuilder<OrderRow>()
                .dataSource(dataSource)
                .sql("insert into imported_order(id,customer,amount) "
                        + "values (:id,:customer,:amount)")
                .itemSqlParameterSourceProvider(item -> new MapSqlParameterSource()
                        .addValue("id", item.id())
                        .addValue("customer", item.customer())
                        .addValue("amount", item.amount()))
                .build();
    }

    @Bean
    Step importOrders(
            JobRepository jobRepository,
            PlatformTransactionManager transactionManager,
            FlatFileItemReader<OrderRow> orderReader,
            ItemProcessor<OrderRow, OrderRow> positiveAmountProcessor,
            JdbcBatchItemWriter<OrderRow> orderWriter) {
        return new StepBuilder("importOrders", jobRepository)
                .<OrderRow, OrderRow>chunk(10, transactionManager)
                .reader(orderReader)
                .processor(positiveAmountProcessor)
                .writer(orderWriter)
                .build();
    }

    @Bean
    Job importOrderJob(JobRepository jobRepository, Step importOrders) {
        return new JobBuilder("importOrderJob", jobRepository)
                .start(importOrders)
                .build();
    }
}

package at.aydin.lab.batch.modern;

import org.junit.jupiter.api.Test;
import java.math.BigDecimal;
import static org.junit.jupiter.api.Assertions.assertEquals;

class BatchConfigurationTest {
    @Test
    void recordKeepsValues() {
        OrderRow row = new OrderRow(1, "Test", new BigDecimal("10.00"));
        assertEquals("Test", row.customer());
    }
}