Retry on generating unique identifiers with MongoDB

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/mongodb/MongoSequenceIncrementer.java

@@ -19,7 +19,11 @@
 import com.mongodb.client.model.ReturnDocument;
 import org.bson.Document;
 
+import org.springframework.core.retry.RetryException;
+import org.springframework.core.retry.RetryPolicy;
+import org.springframework.core.retry.RetryTemplate;
 import org.springframework.dao.DataAccessException;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.data.mongodb.core.MongoOperations;
 import org.springframework.jdbc.support.incrementer.DataFieldMaxValueIncrementer;
 
@@ -29,10 +33,14 @@
 /**
  * @author Mahmoud Ben Hassine
  * @author Christoph Strobl
+ * @author Yanming Zhou
  * @since 5.2.0
  */
 public class MongoSequenceIncrementer implements DataFieldMaxValueIncrementer {
 
+	private final RetryTemplate retryTemplate = new RetryTemplate(
+			RetryPolicy.builder().includes(DataIntegrityViolationException.class).build());
+
 	private final MongoOperations mongoTemplate;
 
 	private final String sequenceName;
@@ -44,11 +52,22 @@ public MongoSequenceIncrementer(MongoOperations mongoTemplate, String sequenceNa
 
 	@Override
 	public long nextLongValue() throws DataAccessException {
-		return mongoTemplate.execute("BATCH_SEQUENCES",
-				collection -> collection
+		try {
+			return retryTemplate
+				.execute(() -> mongoTemplate.execute("BATCH_SEQUENCES", collection -> collection
 					.findOneAndUpdate(new Document("_id", sequenceName), new Document("$inc", new Document("count", 1)),
 							new FindOneAndUpdateOptions().returnDocument(ReturnDocument.AFTER))
-					.getLong("count"));
+					.getLong("count")));
+		}
+		catch (RetryException e) {
+			Throwable cause = e.getCause();
+			if (cause instanceof DataAccessException ex) {
+				throw ex;
+			}
+			else {
+				throw new RuntimeException("Failed to retrieve next value of sequence", e);
+			}
+		}
 	}
 
 	@Override