Add support for annotation based listeners in JobBuilder

Resolves #817

spring-batch-core/src/main/java/org/springframework/batch/core/job/builder/JobBuilderHelper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2011 the original author or authors.
+ * Copyright 2006-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,9 @@
  */
 package org.springframework.batch.core.job.builder;
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
@@ -26,13 +28,18 @@ import org.springframework.batch.core.Job;
 import org.springframework.batch.core.JobExecutionListener;
 import org.springframework.batch.core.JobParametersIncrementer;
 import org.springframework.batch.core.JobParametersValidator;
+import org.springframework.batch.core.annotation.AfterJob;
+import org.springframework.batch.core.annotation.BeforeJob;
 import org.springframework.batch.core.job.AbstractJob;
+import org.springframework.batch.core.listener.JobListenerFactoryBean;
 import org.springframework.batch.core.repository.JobRepository;
+import org.springframework.batch.support.ReflectionUtils;
 
 /**
  * A base class and utility for other job builders providing access to common properties like job repository.
  * 
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * 
  * @since 2.2
  */
@@ -95,6 +102,28 @@ public abstract class JobBuilderHelper<B extends JobBuilderHelper<B>> {
 		return result;
 	}
 
+	/**
+	 * Registers objects using the annotation based listener configuration.
+	 *
+	 * @param listener the object that has a method configured with listener annotation
+	 * @return this for fluent chaining
+	 */
+	public B listener(Object listener) {
+		Set<Method> jobExecutionListenerMethods = new HashSet<>();
+		jobExecutionListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeJob.class));
+		jobExecutionListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterJob.class));
+
+		if(jobExecutionListenerMethods.size() > 0) {
+			JobListenerFactoryBean factory = new JobListenerFactoryBean();
+			factory.setDelegate(listener);
+			properties.addJobExecutionListener((JobExecutionListener) factory.getObject());
+		}
+
+		@SuppressWarnings("unchecked")
+		B result = (B) this;
+		return result;
+	}
+
 	/**
 	 * Register a job execution listener.
 	 * 

spring-batch-core/src/test/java/org/springframework/batch/core/job/builder/JobBuilderTests.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.batch.core.job.builder;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.springframework.batch.core.ExitStatus;
+import org.springframework.batch.core.Job;
+import org.springframework.batch.core.JobExecution;
+import org.springframework.batch.core.JobExecutionListener;
+import org.springframework.batch.core.JobParameters;
+import org.springframework.batch.core.annotation.AfterJob;
+import org.springframework.batch.core.annotation.BeforeJob;
+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.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;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author Mahmoud Ben Hassine
+ */
+public class JobBuilderTests {
+
+	@Test
+	public void testListeners() throws Exception {
+		// given
+		ApplicationContext context = new AnnotationConfigApplicationContext(MyJobConfiguration.class);
+		JobLauncher jobLauncher = context.getBean(JobLauncher.class);
+		Job job = context.getBean(Job.class);
+
+		// when
+		JobExecution jobExecution = jobLauncher.run(job, new JobParameters());
+
+		// then
+		Assert.assertEquals(ExitStatus.COMPLETED, jobExecution.getExitStatus());
+		assertEquals(1, AnnotationBasedJobExecutionListener.beforeJobCount);
+		assertEquals(1, AnnotationBasedJobExecutionListener.afterJobCount);
+		assertEquals(1, InterfaceBasedJobExecutionListener.beforeJobCount);
+		assertEquals(1, InterfaceBasedJobExecutionListener.afterJobCount);
+
+	}
+
+	@Configuration
+	@EnableBatchProcessing
+	static class MyJobConfiguration {
+		@Bean
+		public Job job(JobBuilderFactory jobs, StepBuilderFactory steps) {
+			return jobs.get("job")
+					.listener(new InterfaceBasedJobExecutionListener())
+					.listener(new AnnotationBasedJobExecutionListener())
+					.start(steps.get("step")
+							.tasklet((contribution, chunkContext) -> RepeatStatus.FINISHED)
+							.build())
+					.build();
+		}
+	}
+	
+	static class InterfaceBasedJobExecutionListener implements JobExecutionListener {
+
+		public static int beforeJobCount = 0;
+		public static int afterJobCount = 0;
+
+		@Override
+		public void beforeJob(JobExecution jobExecution) {
+			beforeJobCount++;
+		}
+
+		@Override
+		public void afterJob(JobExecution jobExecution) {
+			afterJobCount++;
+		}
+	}
+
+	static class AnnotationBasedJobExecutionListener {
+
+		public static int beforeJobCount = 0;
+		public static int afterJobCount = 0;
+		
+		@BeforeJob
+		public void beforeJob(JobExecution jobExecution) {
+			beforeJobCount++;
+		}
+
+		@AfterJob
+		public void afterJob(JobExecution jobExecution) {
+			afterJobCount++;
+		}
+	}
+
+}