Refine contribution #3934

* Add default methods in all listener interfaces
* Remove usage of newly deprecated support classes

Issue #3924

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/ItemProcessListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2018 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -35,7 +35,8 @@ public interface ItemProcessListener<T, S> extends StepListener {
 	 * 
 	 * @param item to be processed.
 	 */
-	void beforeProcess(T item);
+	default void beforeProcess(T item) {
+	}
 
 	/**
 	 * Called after {@link ItemProcessor#process(Object)} returns.  If the
@@ -45,13 +46,15 @@ public interface ItemProcessListener<T, S> extends StepListener {
 	 * @param item to be processed
 	 * @param result of processing
 	 */
-	void afterProcess(T item, @Nullable S result);
+	default void afterProcess(T item, @Nullable S result) {
+	}
 
 	/**
 	 * Called if an exception was thrown from {@link ItemProcessor#process(Object)}.
 	 * 
 	 * @param item attempted to be processed
 	 * @param e - exception thrown during processing.
 	 */
-	void onProcessError(T item, Exception e);
+	default void onProcessError(T item, Exception e) {
+	}
 }

spring-batch-core/src/main/java/org/springframework/batch/core/ItemReadListener.java

@@ -30,7 +30,8 @@ public interface ItemReadListener<T> extends StepListener {
 	/**
 	 * Called before {@link ItemReader#read()}
 	 */
-	void beforeRead();
+	default void beforeRead() {
+	}
 
 	/**
 	 * Called after {@link ItemReader#read()}.
@@ -39,12 +40,14 @@ public interface ItemReadListener<T> extends StepListener {
 	 * 
 	 * @param item returned from read()
 	 */
-	void afterRead(T item);
+	default void afterRead(T item) {
+	}
 
 	/**
 	 * Called if an error occurs while trying to read.
 	 * 
 	 * @param ex thrown from {@link ItemReader}
 	 */
-	void onReadError(Exception ex);
+	default void onReadError(Exception ex) {
+	}
 }

spring-batch-core/src/main/java/org/springframework/batch/core/ItemWriteListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -38,6 +38,7 @@
  *</p>
  *
  * @author Lucas Ward
+ * @author Mahmoud Ben Hassine
  *
  */
 public interface ItemWriteListener<S> extends StepListener {
@@ -47,7 +48,8 @@ public interface ItemWriteListener<S> extends StepListener {
 	 *
 	 * @param items to be written
 	 */
-	void beforeWrite(List<? extends S> items);
+	default void beforeWrite(List<? extends S> items) {
+	}
 
 	/**
 	 * Called after {@link ItemWriter#write(java.util.List)} This will be
@@ -56,7 +58,8 @@ public interface ItemWriteListener<S> extends StepListener {
 	 *
 	 * @param items written items
 	 */
-	void afterWrite(List<? extends S> items);
+	default void afterWrite(List<? extends S> items) {
+	}
 
 	/**
 	 * Called if an error occurs while trying to write. Will be called inside a
@@ -67,5 +70,6 @@ public interface ItemWriteListener<S> extends StepListener {
 	 * @param exception thrown from {@link ItemWriter}
 	 * @param items attempted to be written.
 	 */
-	void onWriteError(Exception exception, List<? extends S> items);
+	default void onWriteError(Exception exception, List<? extends S> items) {
+	}
 }

spring-batch-core/src/main/java/org/springframework/batch/core/SkipListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -25,6 +25,7 @@
  * 
  * @author Dave Syer
  * @author Robert Kasanicky
+ * @author Mahmoud Ben Hassine
  * 
  */
 public interface SkipListener<T,S> extends StepListener {
@@ -37,7 +38,8 @@ public interface SkipListener<T,S> extends StepListener {
 	 * 
 	 * @param t cause of the failure
 	 */
-	void onSkipInRead(Throwable t);
+	default void onSkipInRead(Throwable t) {
+	}
 
 	/**
 	 * This item failed on write with the given exception, and a skip was called
@@ -46,7 +48,8 @@ public interface SkipListener<T,S> extends StepListener {
 	 * @param item the failed item
 	 * @param t the cause of the failure
 	 */
-	void onSkipInWrite(S item, Throwable t);
+	default void onSkipInWrite(S item, Throwable t) {
+	}
 
 	/**
 	 * This item failed on processing with the given exception, and a skip was called
@@ -55,6 +58,7 @@ public interface SkipListener<T,S> extends StepListener {
 	 * @param item the failed item
 	 * @param t the cause of the failure
 	 */
-	void onSkipInProcess(T item, Throwable t);
+	default void onSkipInProcess(T item, Throwable t) {
+	}
 
 }

spring-batch-core/src/main/java/org/springframework/batch/core/listener/ExecutionContextPromotionListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2019 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -19,6 +19,7 @@
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.Step;
 import org.springframework.batch.core.StepExecution;
+import org.springframework.batch.core.StepExecutionListener;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.support.PatternMatcher;
 import org.springframework.beans.factory.InitializingBean;
@@ -37,9 +38,10 @@
  * promotion will only occur for steps with an exit code of "COMPLETED".
  *
  * @author Dan Garrette
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  */
-public class ExecutionContextPromotionListener extends StepExecutionListenerSupport implements InitializingBean {
+public class ExecutionContextPromotionListener implements StepExecutionListener, InitializingBean {
 
 	private String[] keys = null;
 

spring-batch-core/src/main/java/org/springframework/batch/core/listener/ItemListenerSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2018 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -34,87 +34,4 @@
  */
 public class ItemListenerSupport<I, O> implements ItemReadListener<I>, ItemProcessListener<I, O>, ItemWriteListener<O> {
 
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemReadListener#afterRead(java.lang.Object)
-	 */
-	@Override
-	public void afterRead(I item) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemReadListener#beforeRead()
-	 */
-	@Override
-	public void beforeRead() {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemReadListener#onReadError(java.lang.Exception)
-	 */
-	@Override
-	public void onReadError(Exception ex) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.ItemProcessListener#afterProcess(java.lang.Object,
-	 *      java.lang.Object)
-	 */
-	@Override
-	public void afterProcess(I item, @Nullable O result) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.ItemProcessListener#beforeProcess(java.lang.Object)
-	 */
-	@Override
-	public void beforeProcess(I item) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.ItemProcessListener#onProcessError(java.lang.Object,
-	 *      java.lang.Exception)
-	 */
-	@Override
-	public void onProcessError(I item, Exception e) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemWriteListener#afterWrite()
-	 */
-	@Override
-	public void afterWrite(List<? extends O> item) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemWriteListener#beforeWrite(java.lang.Object)
-	 */
-	@Override
-	public void beforeWrite(List<? extends O> item) {
-	}
-
-	/*
-	 * (non-Javadoc)
-	 *
-	 * @see org.springframework.batch.core.domain.ItemWriteListener#onWriteError(java.lang.Exception,
-	 *      java.lang.Object)
-	 */
-	@Override
-	public void onWriteError(Exception ex, List<? extends O> item) {
-	}
 }

spring-batch-core/src/main/java/org/springframework/batch/core/listener/JobParameterExecutionContextCopyListener.java

@@ -21,6 +21,7 @@
 import org.springframework.batch.core.JobParameters;
 import org.springframework.batch.core.Step;
 import org.springframework.batch.core.StepExecution;
+import org.springframework.batch.core.StepExecutionListener;
 import org.springframework.batch.item.ExecutionContext;
 
 /**
@@ -30,9 +31,10 @@
  * {@link ExecutionContext} that should be copied.
  * 
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  */
-public class JobParameterExecutionContextCopyListener extends StepExecutionListenerSupport {
+public class JobParameterExecutionContextCopyListener implements StepExecutionListener {
 
 	private Collection<String> keys = null;
 

spring-batch-core/src/main/java/org/springframework/batch/core/listener/SkipListenerSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2021 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.
@@ -21,8 +21,12 @@
  * Basic no-op implementations of all {@link SkipListener} implementations.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
+ *
+ * @deprecated as of v5.0 in favor of the default methods in {@link SkipListener}.
  *
  */
+@Deprecated
 public class SkipListenerSupport<T,S> implements SkipListener<T,S> {
 
 	/* (non-Javadoc)