Support interface based listener registration

Author: uyw4687

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

@@ -261,7 +261,7 @@ protected JobRepository getJobRepository() {
 	 * @throws JobExecutionException to signal a fatal batch framework error (not a
 	 * business or validation exception)
 	 */
-	abstract protected void doExecute(JobExecution execution) throws JobExecutionException;
+	protected abstract void doExecute(JobExecution execution) throws JobExecutionException;
 
 	/**
 	 * Run the specified job, handling all listener and repository calls, and delegating

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

@@ -15,18 +15,14 @@
  */
 package org.springframework.batch.core.job.builder;
 
-import java.lang.reflect.Method;
+import java.lang.annotation.Annotation;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.observation.ObservationRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.batch.core.JobExecutionListener;
 import org.springframework.batch.core.JobParametersIncrementer;
 import org.springframework.batch.core.JobParametersValidator;
@@ -39,13 +35,17 @@
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.support.ReflectionUtils;
 
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.observation.ObservationRegistry;
+
 /**
  * A base class and utility for other job builders providing access to common properties
  * like job repository.
  *
  * @author Dave Syer
  * @author Mahmoud Ben Hassine
  * @author Taeik Lim
+ * @author Seonkyo Ok
  * @since 2.2
  */
 public abstract class JobBuilderHelper<B extends JobBuilderHelper<B>> {
@@ -167,14 +167,10 @@ public B meterRegistry(MeterRegistry meterRegistry) {
 	 * @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());
+		final List<Class<? extends Annotation>> targetAnnotations = List.of(BeforeJob.class, AfterJob.class);
+		if (listener instanceof JobExecutionListener ||
+				ReflectionUtils.hasMethodWithAnyAnnotation(listener.getClass(), targetAnnotations)) {
+			properties.addJobExecutionListener(JobListenerFactoryBean.getListener(listener));
 		}
 
 		@SuppressWarnings("unchecked")

spring-batch-core/src/main/java/org/springframework/batch/core/step/builder/AbstractTaskletStepBuilder.java

@@ -15,9 +15,9 @@
  */
 package org.springframework.batch.core.step.builder;
 
-import java.lang.reflect.Method;
-import java.util.HashSet;
+import java.lang.annotation.Annotation;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 
 import org.springframework.batch.core.ChunkListener;
@@ -50,6 +50,7 @@
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
  * @author Ilpyo Yang
+ * @author Seonkyo Ok
  * @since 2.2
  * @param <B> the type of builder represented
  */
@@ -175,15 +176,11 @@ public B listener(ChunkListener listener) {
 	public B listener(Object listener) {
 		super.listener(listener);
 
-		Set<Method> chunkListenerMethods = new HashSet<>();
-		chunkListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeChunk.class));
-		chunkListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterChunk.class));
-		chunkListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterChunkError.class));
-
-		if (!chunkListenerMethods.isEmpty()) {
-			StepListenerFactoryBean factory = new StepListenerFactoryBean();
-			factory.setDelegate(listener);
-			this.listener((ChunkListener) factory.getObject());
+		final List<Class<? extends Annotation>> targetAnnotations = List.of(
+				BeforeChunk.class, AfterChunk.class, AfterChunkError.class);
+		if (listener instanceof ChunkListener ||
+				ReflectionUtils.hasMethodWithAnyAnnotation(listener.getClass(), targetAnnotations)) {
+			this.listener((ChunkListener) StepListenerFactoryBean.getListener(listener));
 		}
 
 		return self();

spring-batch-core/src/main/java/org/springframework/batch/core/step/builder/FaultTolerantStepBuilder.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.batch.core.step.builder;
 
-import java.lang.reflect.Method;
+import java.lang.annotation.Annotation;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -90,6 +90,7 @@
  * @author Chris Schaefer
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
+ * @author Seonkyo Ok
  * @since 2.2
  */
 public class FaultTolerantStepBuilder<I, O> extends SimpleStepBuilder<I, O> {
@@ -194,15 +195,11 @@ protected Tasklet createTasklet() {
 	public FaultTolerantStepBuilder<I, O> listener(Object listener) {
 		super.listener(listener);
 
-		Set<Method> skipListenerMethods = new HashSet<>();
-		skipListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnSkipInRead.class));
-		skipListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnSkipInProcess.class));
-		skipListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnSkipInWrite.class));
-
-		if (!skipListenerMethods.isEmpty()) {
-			StepListenerFactoryBean factory = new StepListenerFactoryBean();
-			factory.setDelegate(listener);
-			skipListeners.add((SkipListener<I, O>) factory.getObject());
+		final List<Class<? extends Annotation>> targetAnnotations = List.of(
+				OnSkipInRead.class, OnSkipInProcess.class, OnSkipInWrite.class);
+		if (listener instanceof SkipListener<?,?> ||
+				ReflectionUtils.hasMethodWithAnyAnnotation(listener.getClass(), targetAnnotations)) {
+			skipListeners.add((SkipListener<I, O>) StepListenerFactoryBean.getListener(listener));
 		}
 
 		return this;

spring-batch-core/src/main/java/org/springframework/batch/core/step/builder/SimpleStepBuilder.java

@@ -15,15 +15,12 @@
  */
 package org.springframework.batch.core.step.builder;
 
-import java.lang.reflect.Method;
+import java.lang.annotation.Annotation;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Metrics;
-
 import org.springframework.batch.core.ChunkListener;
 import org.springframework.batch.core.ItemProcessListener;
 import org.springframework.batch.core.ItemReadListener;
@@ -56,6 +53,9 @@
 import org.springframework.batch.support.ReflectionUtils;
 import org.springframework.util.Assert;
 
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Metrics;
+
 /**
  * Step builder for simple item processing (chunk oriented) steps. Items are read and
  * cached in chunks, and then processed (transformed) and written (optionally the
@@ -65,6 +65,7 @@
  * @author Dave Syer
  * @author Mahmoud Ben Hassine
  * @author Parikshit Dutta
+ * @author Seonkyo Ok
  * @since 2.2
  */
 public class SimpleStepBuilder<I, O> extends AbstractTaskletStepBuilder<SimpleStepBuilder<I, O>> {
@@ -258,21 +259,15 @@ public SimpleStepBuilder<I, O> readerIsTransactionalQueue() {
 	public SimpleStepBuilder<I, O> listener(Object listener) {
 		super.listener(listener);
 
-		Set<Method> itemListenerMethods = new HashSet<>();
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeRead.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterRead.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeProcess.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterProcess.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeWrite.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterWrite.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnReadError.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnProcessError.class));
-		itemListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), OnWriteError.class));
-
-		if (!itemListenerMethods.isEmpty()) {
-			StepListenerFactoryBean factory = new StepListenerFactoryBean();
-			factory.setDelegate(listener);
-			itemListeners.add((StepListener) factory.getObject());
+		final List<Class<? extends Annotation>> targetAnnotations = List.of(
+				BeforeRead.class, AfterRead.class, OnReadError.class,
+				BeforeProcess.class, AfterProcess.class, OnProcessError.class,
+				BeforeWrite.class, AfterWrite.class, OnWriteError.class);
+		if (listener instanceof ItemReadListener<?> ||
+				listener instanceof ItemProcessListener<?, ?> ||
+				listener instanceof ItemWriteListener<?> ||
+				ReflectionUtils.hasMethodWithAnyAnnotation(listener.getClass(), targetAnnotations)) {
+			itemListeners.add(StepListenerFactoryBean.getListener(listener));
 		}
 
 		return this;

spring-batch-core/src/main/java/org/springframework/batch/core/step/builder/StepBuilderHelper.java

@@ -15,18 +15,12 @@
  */
 package org.springframework.batch.core.step.builder;
 
-import java.lang.reflect.Method;
+import java.lang.annotation.Annotation;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Metrics;
-import io.micrometer.observation.ObservationRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.batch.core.StepExecutionListener;
 import org.springframework.batch.core.annotation.AfterStep;
 import org.springframework.batch.core.annotation.BeforeStep;
@@ -37,6 +31,10 @@
 import org.springframework.batch.core.step.AbstractStep;
 import org.springframework.batch.support.ReflectionUtils;
 
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Metrics;
+import io.micrometer.observation.ObservationRegistry;
+
 /**
  * A base class and utility for other step builders providing access to common properties
  * like job repository and listeners.
@@ -45,6 +43,7 @@
  * @author Michael Minella
  * @author Taeik Lim
  * @author Mahmoud Ben Hassine
+ * @author Seonkyo Ok
  * @since 2.2
  */
 public abstract class StepBuilderHelper<B extends StepBuilderHelper<B>> {
@@ -129,14 +128,10 @@ public B startLimit(int startLimit) {
 	 * @return this for fluent chaining
 	 */
 	public B listener(Object listener) {
-		Set<Method> stepExecutionListenerMethods = new HashSet<>();
-		stepExecutionListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), BeforeStep.class));
-		stepExecutionListenerMethods.addAll(ReflectionUtils.findMethod(listener.getClass(), AfterStep.class));
-
-		if (stepExecutionListenerMethods.size() > 0) {
-			StepListenerFactoryBean factory = new StepListenerFactoryBean();
-			factory.setDelegate(listener);
-			properties.addStepExecutionListener((StepExecutionListener) factory.getObject());
+		final List<Class<? extends Annotation>> targetAnnotations = List.of(BeforeStep.class, AfterStep.class);
+		if (listener instanceof StepExecutionListener ||
+				ReflectionUtils.hasMethodWithAnyAnnotation(listener.getClass(), targetAnnotations)) {
+			properties.addStepExecutionListener((StepExecutionListener) StepListenerFactoryBean.getListener(listener));
 		}
 
 		return self();