ExceptionClassifier Reverse Option

Option to not retry by default and retry specific.

* Polishing and Tests

In preparation for #2124

Author: garyrussell

Diff for: spring-kafka/src/main/java/org/springframework/kafka/listener/ExceptionClassifier.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 the original author or authors.
+ * Copyright 2021-2022 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.
@@ -55,6 +55,16 @@ private static ExtendedBinaryExceptionClassifier configureDefaultClassifier() {
 		return new ExtendedBinaryExceptionClassifier(classified, true);
 	}
 
+	/**
+	 * By default, unmatched types classify as true. Call this method to make the default
+	 * false, and remove types explicitly classified as false. This should be called before
+	 * calling any of the classification modification methods.
+	 * @since 2.8.4
+	 */
+	public void defaultFalse() {
+		this.classifier = new ExtendedBinaryExceptionClassifier(new HashMap<>(), false);
+	}
+
 	/**
 	 * Return the exception classifier.
 	 * @return the classifier.
@@ -97,20 +107,39 @@ public void setClassifications(Map<Class<? extends Throwable>, Boolean> classifi
 	 * <li>{@link NoSuchMethodException}</li>
 	 * <li>{@link ClassCastException}</li>
 	 * </ul>
-	 * All others will be retried.
+	 * All others will be retried, unless {@link #defaultFalse()} has been called.
 	 * @param exceptionTypes the exception types.
-	 * @see #removeNotRetryableException(Class)
+	 * @see #removeClassification(Class)
 	 * @see #setClassifications(Map, boolean)
 	 */
 	@SafeVarargs
 	@SuppressWarnings("varargs")
 	public final void addNotRetryableExceptions(Class<? extends Exception>... exceptionTypes) {
+		add(false, exceptionTypes);
+	}
+
+	/**
+	 * Add exception types that can be retried. Call this after {@link #defaultFalse()} to
+	 * specify those exception types that should be classified as true.
+	 * All others will be retried, unless {@link #defaultFalse()} has been called.
+	 * @param exceptionTypes the exception types.
+	 * @since 2.8.4
+	 * @see #removeClassification(Class)
+	 * @see #setClassifications(Map, boolean)
+	 */
+	@SafeVarargs
+	@SuppressWarnings("varargs")
+	public final void addRetryableExceptions(Class<? extends Exception>... exceptionTypes) {
+		add(true, exceptionTypes);
+	}
+
+	private void add(boolean classified, Class<? extends Exception>... exceptionTypes) {
 		Assert.notNull(exceptionTypes, "'exceptionTypes' cannot be null");
 		Assert.noNullElements(exceptionTypes, "'exceptionTypes' cannot contain nulls");
 		for (Class<? extends Exception> exceptionType : exceptionTypes) {
 			Assert.isTrue(Exception.class.isAssignableFrom(exceptionType),
 					() -> "exceptionType " + exceptionType + " must be an Exception");
-			this.classifier.getClassified().put(exceptionType, false);
+			this.classifier.getClassified().put(exceptionType, classified);
 		}
 	}
 
@@ -125,13 +154,38 @@ public final void addNotRetryableExceptions(Class<? extends Exception>... except
 	 * <li>{@link NoSuchMethodException}</li>
 	 * <li>{@link ClassCastException}</li>
 	 * </ul>
-	 * All others will be retried.
+	 * All others will be retried, unless {@link #defaultFalse()} has been called.
 	 * @param exceptionType the exception type.
 	 * @return true if the removal was successful.
+	 * @deprecated in favor of {@link #removeClassification(Class)}
 	 * @see #addNotRetryableExceptions(Class...)
 	 * @see #setClassifications(Map, boolean)
+	 * @see #defaultFalse()
 	 */
+	@Deprecated
 	public boolean removeNotRetryableException(Class<? extends Exception> exceptionType) {
+		return this.removeClassification(exceptionType);
+	}
+
+	/**
+	 * Remove an exception type from the configured list. By default, the following
+	 * exceptions will not be retried:
+	 * <ul>
+	 * <li>{@link DeserializationException}</li>
+	 * <li>{@link MessageConversionException}</li>
+	 * <li>{@link ConversionException}</li>
+	 * <li>{@link MethodArgumentResolutionException}</li>
+	 * <li>{@link NoSuchMethodException}</li>
+	 * <li>{@link ClassCastException}</li>
+	 * </ul>
+	 * All others will be retried, unless {@link #defaultFalse()} has been called.
+	 * @param exceptionType the exception type.
+	 * @return true if the removal was successful.
+	 * @since 2.8.4
+	 * @see #addNotRetryableExceptions(Class...)
+	 * @see #setClassifications(Map, boolean)
+	 */
+	public boolean removeClassification(Class<? extends Exception> exceptionType) {
 		return this.classifier.getClassified().remove(exceptionType);
 	}
 

Diff for: spring-kafka/src/main/java/org/springframework/kafka/retrytopic/DeadLetterPublishingRecovererFactory.java

@@ -143,7 +143,7 @@ protected DeadLetterPublishingRecoverer.HeaderNames getHeaderNames() {
 		recoverer.setSkipSameTopicFatalExceptions(false);
 		this.recovererCustomizer.accept(recoverer);
 		this.fatalExceptions.forEach(recoverer::addNotRetryableExceptions);
-		this.nonFatalExceptions.forEach(recoverer::removeNotRetryableException);
+		this.nonFatalExceptions.forEach(recoverer::removeClassification);
 		return recoverer;
 	}
 

Diff for: spring-kafka/src/test/java/org/springframework/kafka/listener/DeadLetterPublishingRecovererTests.java

@@ -559,7 +559,7 @@ void noCircularRoutingIfFatal() {
 		recoverer.addNotRetryableExceptions(IllegalStateException.class);
 		recoverer.accept(record, new IllegalStateException());
 		verify(template, never()).send(any(ProducerRecord.class));
-		recoverer.removeNotRetryableException(IllegalStateException.class);
+		recoverer.removeClassification(IllegalStateException.class);
 		recoverer.setFailIfSendResultIsError(false);
 		recoverer.accept(record, new IllegalStateException());
 		verify(template).send(any(ProducerRecord.class));
@@ -580,7 +580,7 @@ void doNotSkipCircularFatalIfSet() {
 		recoverer.addNotRetryableExceptions(IllegalStateException.class);
 		recoverer.accept(record, new IllegalStateException());
 		verify(template, times(2)).send(any(ProducerRecord.class));
-		recoverer.removeNotRetryableException(IllegalStateException.class);
+		recoverer.removeClassification(IllegalStateException.class);
 		recoverer.setFailIfSendResultIsError(false);
 		recoverer.accept(record, new IllegalStateException());
 		verify(template, times(3)).send(any(ProducerRecord.class));

Diff for: spring-kafka/src/test/java/org/springframework/kafka/listener/ExceptionClassifierTests.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2022 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.kafka.listener;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author Gary Russell
+ * @since 2.8.4
+ *
+ */
+public class ExceptionClassifierTests {
+
+	@Test
+	void testDefault() {
+		ExceptionClassifier ec = new ExceptionClassifier() {
+		};
+		assertThat(ec.getClassifier().classify(new Exception())).isTrue();
+		assertThat(ec.getClassifier().classify(new ClassCastException())).isFalse();
+		ec.removeClassification(ClassCastException.class);
+		assertThat(ec.getClassifier().classify(new ClassCastException())).isTrue();
+		assertThat(ec.getClassifier().classify(new IllegalStateException())).isTrue();
+		ec.addNotRetryableExceptions(IllegalStateException.class);
+		assertThat(ec.getClassifier().classify(new IllegalStateException())).isFalse();
+	}
+
+	@Test
+	void testDefaultFalse() {
+		ExceptionClassifier ec = new ExceptionClassifier() {
+		};
+		assertThat(ec.getClassifier().classify(new Exception())).isTrue();
+		ec.defaultFalse();
+		assertThat(ec.getClassifier().classify(new Exception())).isFalse();
+		assertThat(ec.getClassifier().classify(new IllegalStateException())).isFalse();
+		ec.addRetryableExceptions(IllegalStateException.class);
+		assertThat(ec.getClassifier().classify(new IllegalStateException())).isTrue();
+		ec.removeClassification(IllegalStateException.class);
+		assertThat(ec.getClassifier().classify(new IllegalStateException())).isFalse();
+	}
+
+}