Using 'JobExecutionDecider' we can decide which step should be executed depends on the previous step status.
For example, as you see above image, If step 1 status is passed, then decider choose to execute step 2 else decider choose to execute step3.
How to achieve above behaviour?
Step 1: Create a step, that set the status of its execution.
Step 2: Create custom Job Execution Decider by implementing JobExecutionDecider interface.
@Component
public class MyJobExecutionDecider implements JobExecutionDecider {
@Override
public FlowExecutionStatus decide(JobExecution jobExecution, StepExecution stepExecution) {
ExecutionContext jobExecutionContext = stepExecution.getJobExecution().getExecutionContext();
String data = jobExecutionContext.getString("status");
if ("passed".equals(data)) {
return new FlowExecutionStatus("LEFT");
} else {
return new FlowExecutionStatus("RIGHT");
}
}
}
Step 3: Create a job using the JobDecider created in step 2.
@Bean
public Job job() {
return jobBuilderFactory.get("My-Job").start(step1()).next(decider)
.from(decider).on("LEFT").to(step2())
.from(decider).on("RIGHT").to(step3())
.end().build();
}
As you see above snippet, if the decider choose LEFT, then step2 gets executed and if decider choose RIGHT step3 gets executed.
Find the below working application.
Step 1: Create new maven project ‘job-decider-demo’.
Step 2: Update pom.xml with maven dependencies.
pom.xml
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample.app</groupId>
<artifactId>job-decider-demo</artifactId>
<version>1</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.springframework.batch/spring-batch-core -->
<dependency>
<groupId>org.springframework.batch</groupId>
<artifactId>spring-batch-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
</dependencies>
</project>
Step 3: Create new package ‘com.sample.app.configuration’ and define JobConfiguration.
JobConfiguration.java
package com.sample.app.configuration;
import java.util.Random;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
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.scope.context.ChunkContext;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.sample.app.deciders.MyJobExecutionDecider;
@Configuration
@EnableBatchProcessing
public class JobConfiguration {
@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;
@Autowired
private MyJobExecutionDecider decider;
private static Random random = new Random();
public boolean isTestPassed() {
return random.nextInt() % 2 == 0;
}
@Bean
public Step step1() {
return this.stepBuilderFactory.get("My-Step1")
.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
if (isTestPassed()) {
chunkContext.getStepContext().getStepExecution().getJobExecution().getExecutionContext()
.put("status", "passed");
System.out.println("test1 is passed");
} else {
chunkContext.getStepContext().getStepExecution().getJobExecution().getExecutionContext()
.put("status", "failed");
System.out.println("test1 is failed");
}
return RepeatStatus.FINISHED;
}).build();
}
@Bean
public Step step2() {
return this.stepBuilderFactory.get("My-Step2")
.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
System.out.println("Executing step 2");
return RepeatStatus.FINISHED;
}).build();
}
@Bean
public Step step3() {
return this.stepBuilderFactory.get("My-Step3")
.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
System.out.println("Executing step 3");
return RepeatStatus.FINISHED;
}).build();
}
@Bean
public Job job() {
return jobBuilderFactory.get("My-Job").start(step1()).next(decider)
.from(decider).on("LEFT").to(step2())
.from(decider).on("RIGHT").to(step3())
.end().build();
}
}
Step 4: Create package ‘com.sample.app.deciders’ and define MyJobExecutionDecider.
MyJobExecutionDecider.java
package com.sample.app.deciders;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.job.flow.FlowExecutionStatus;
import org.springframework.batch.core.job.flow.JobExecutionDecider;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.stereotype.Component;
@Component
public class MyJobExecutionDecider implements JobExecutionDecider {
@Override
public FlowExecutionStatus decide(JobExecution jobExecution, StepExecution stepExecution) {
ExecutionContext jobExecutionContext = stepExecution.getJobExecution().getExecutionContext();
String data = jobExecutionContext.getString("status");
if ("passed".equals(data)) {
return new FlowExecutionStatus("LEFT");
} else {
return new FlowExecutionStatus("RIGHT");
}
}
}
Step 5: Define App.java
App.java
package com.sample.app;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@EnableBatchProcessing
@SpringBootApplication
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
Step 6: Create application.properties under src/main/resources folder.
application.properties
logging.level.root=ERROR logging.level.org.hibernate=ERROR ## H2 specific properties spring.h2.console.enabled=true spring.h2.console.path=/h2 spring.datasource.url=jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1; spring.datasource.username=krishna spring.datasource.password=password123 spring.datasource.driverClassName=org.h2.Driver ## JPA specific properties # Creates the schema, destroying previous data. spring.jpa.hibernate.ddl-auto=create spring.jpa.database-platform=org.hibernate.dialect.H2Dialect spring.jpa.show-sql=false spring.jpa.properties.hibernate.format_sql=false ## Database connection pooling properties # Number of ms to wait before throwing an exception if no connection is available. spring.datasource.max-wait=10000 # Maximum number of active connections that can be allocated from this pool at the same time. spring.datasource.tomcat.max-active=10 spring.datasource.tomcat.max-idle=5 spring.datasource.tomcat.min-idle=3
Total project structure looks like below.
Run App.java to run the application.
Note: Remove database file located at '~/db/myOrg.db' and rerun the application.
On Test Run 1
test1 is passed
Executing step 2
On Test Run 2
test1 is failed
Executing step 3
You can download complete working application from this link.
https://github.com/harikrishna553/springboot/tree/master/batch/job-decider-demo
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