From 2c1a3cf03e85fb8d1af3d5464837412f6bc368fc Mon Sep 17 00:00:00 2001
From: Mark Paluch <mpaluch@pivotal.io>
Date: Thu, 16 Jul 2020 09:41:46 +0200
Subject: [PATCH] DATAMONGO-2536 - Polishing.

Encapsulate skipResults in AggregationOptions. Reformat code. Add override Javadoc.

Original pull request: #876.
---
 .../data/mongodb/core/MongoTemplate.java      |   8 +-
 .../mongodb/core/ReactiveMongoTemplate.java   |  19 +--
 .../core/aggregation/AddFieldsOperation.java  |   4 +
 .../mongodb/core/aggregation/Aggregation.java |   8 +-
 .../aggregation/AggregationOperation.java     |   9 +-
 .../core/aggregation/AggregationOptions.java  |  13 +-
 .../core/aggregation/AggregationPipeline.java |   4 +-
 .../core/aggregation/BucketAutoOperation.java |  11 +-
 .../core/aggregation/BucketOperation.java     |  20 ++-
 .../core/aggregation/CountOperation.java      |   4 +-
 .../DocumentEnhancingOperation.java           |   6 +-
 .../core/aggregation/FacetOperation.java      |  11 +-
 .../core/aggregation/GeoNearOperation.java    |  21 ++-
 .../aggregation/GraphLookupOperation.java     |   4 +-
 .../core/aggregation/GroupOperation.java      |   8 +-
 .../core/aggregation/LimitOperation.java      |   8 +-
 .../core/aggregation/LiteralOperators.java    |   4 +
 .../core/aggregation/LookupOperation.java     |  11 +-
 .../core/aggregation/MatchOperation.java      |  11 +-
 .../core/aggregation/MergeOperation.java      |  10 +-
 .../core/aggregation/OutOperation.java        |   9 +-
 .../core/aggregation/ProjectionOperation.java |  14 +-
 .../core/aggregation/RedactOperation.java     |   8 +-
 .../aggregation/ReplaceRootOperation.java     |   6 +-
 .../core/aggregation/SampleOperation.java     |   8 +-
 .../core/aggregation/SetOperation.java        |   4 +
 .../core/aggregation/SkipOperation.java       |  11 +-
 .../aggregation/SortByCountOperation.java     |  10 +-
 .../core/aggregation/SortOperation.java       |  11 +-
 .../core/aggregation/UnsetOperation.java      |  12 +-
 .../core/aggregation/UnwindOperation.java     |  13 +-
 .../core/aggregation/AggregationTests.java    | 160 +++++++++---------
 .../aggregation/ReactiveAggregationTests.java |   1 -
 33 files changed, 278 insertions(+), 183 deletions(-)

diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
index 1b1ad7d33..acdcfd7a9 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
@@ -28,6 +28,7 @@ import org.bson.Document;
 import org.bson.conversions.Bson;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -62,7 +63,6 @@ import org.springframework.data.mongodb.core.QueryOperations.UpdateContext;
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.AggregationOptions;
-import org.springframework.data.mongodb.core.aggregation.AggregationOptions.ResultOptions;
 import org.springframework.data.mongodb.core.aggregation.AggregationResults;
 import org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
@@ -2132,7 +2132,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 			List<Document> rawResult = new ArrayList<>();
 
-			Class<?> domainType = aggregation instanceof TypedAggregation ? ((TypedAggregation) aggregation).getInputType()
+			Class<?> domainType = aggregation instanceof TypedAggregation ? ((TypedAggregation<?>) aggregation).getInputType()
 					: null;
 
 			Optional<Collation> collation = Optionals.firstNonEmpty(options::getCollation,
@@ -2153,10 +2153,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 				aggregateIterable = aggregateIterable.maxTime(options.getMaxTime().toMillis(), TimeUnit.MILLISECONDS);
 			}
 
-			if(ResultOptions.SKIP.equals(options.resultOptions())) {
+			if (options.isSkipResults()) {
 
 				// toCollection only allowed for $out and $merge if those are the last stages
-				if(aggregation.getPipeline().isOutOrMerge()) {
+				if (aggregation.getPipeline().isOutOrMerge()) {
 					aggregateIterable.toCollection();
 				} else {
 					aggregateIterable.first();
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
index 4688df6c7..da60cd671 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
@@ -26,7 +26,6 @@ import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 import java.util.function.Function;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import org.bson.BsonValue;
@@ -37,6 +36,7 @@ import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscriber;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -69,7 +69,6 @@ import org.springframework.data.mongodb.core.QueryOperations.UpdateContext;
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.AggregationOptions;
-import org.springframework.data.mongodb.core.aggregation.AggregationOptions.ResultOptions;
 import org.springframework.data.mongodb.core.aggregation.PrefixingDelegatingAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
@@ -1006,11 +1005,14 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 		}
 
 		ReadDocumentCallback<O> readCallback = new ReadDocumentCallback<>(mongoConverter, outputType, collectionName);
-		return execute(collectionName, collection -> aggregateAndMap(collection, pipeline, () -> aggregation.getPipeline().isOutOrMerge(), options, readCallback,
-				aggregation instanceof TypedAggregation ? ((TypedAggregation) aggregation).getInputType() : null));
+		return execute(collectionName,
+				collection -> aggregateAndMap(collection, pipeline, aggregation.getPipeline().isOutOrMerge(), options,
+						readCallback,
+						aggregation instanceof TypedAggregation ? ((TypedAggregation<?>) aggregation).getInputType() : null));
 	}
 
-	private <O> Flux<O> aggregateAndMap(MongoCollection<Document> collection, List<Document> pipeline, Supplier<Boolean> isOutOrMerge,
+	private <O> Flux<O> aggregateAndMap(MongoCollection<Document> collection, List<Document> pipeline,
+			boolean isOutOrMerge,
 			AggregationOptions options, ReadDocumentCallback<O> readCallback, @Nullable Class<?> inputType) {
 
 		AggregatePublisher<Document> cursor = collection.aggregate(pipeline, Document.class)
@@ -1030,11 +1032,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 			cursor = cursor.maxTime(options.getMaxTime().toMillis(), TimeUnit.MILLISECONDS);
 		}
 
-		if (ResultOptions.SKIP.equals(options.resultOptions())) {
-			if (isOutOrMerge.get()) {
-				return Flux.from(cursor.toCollection()).map(it -> (O) it);
-			}
-			return Flux.from(cursor.first()).thenMany(Mono.empty());
+		if (options.isSkipResults()) {
+			return (isOutOrMerge ? Flux.from(cursor.toCollection()) : Flux.from(cursor.first())).thenMany(Mono.empty());
 		}
 
 		return Flux.from(cursor).concatMap(readCallback::doWith);
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AddFieldsOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AddFieldsOperation.java
index 8ebc744ad..449c137b7 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AddFieldsOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AddFieldsOperation.java
@@ -99,6 +99,10 @@ public class AddFieldsOperation extends DocumentEnhancingOperation {
 		return new AddFieldsOperationBuilder(getValueMap());
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.DocumentEnhancingOperation#mongoOperator()
+	 */
 	@Override
 	protected String mongoOperator() {
 		return "$addFields";
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java
index 32c4a441c..df7578125 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java
@@ -645,9 +645,9 @@ public class Aggregation {
 	/**
 	 * Creates a new {@link RedactOperation} that can restrict the content of a document based on information stored
 	 * within the document itself.
-	 * 
+	 *
 	 * <pre class="code">
-	 * 
+	 *
 	 * Aggregation.redact(ConditionalOperators.when(Criteria.where("level").is(5)) //
 	 * 		.then(RedactOperation.PRUNE) //
 	 * 		.otherwise(RedactOperation.DESCEND));
@@ -705,6 +705,10 @@ public class Aggregation {
 		return pipeline.toDocuments(rootContext);
 	}
 
+	/**
+	 * @return the {@link AggregationPipeline}.
+	 * @since 3.0.2
+	 */
 	public AggregationPipeline getPipeline() {
 		return pipeline;
 	}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java
index e611528e7..b22458ad9 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java
@@ -55,7 +55,14 @@ public interface AggregationOperation {
 		return Collections.singletonList(toDocument(context));
 	}
 
-	default String operator() {
+	/**
+	 * Return the MongoDB operator that is used for this {@link AggregationOperation}. Aggregation operations should
+	 * implement this method to avoid document rendering.
+	 *
+	 * @return the operator used for this {@link AggregationOperation}.
+	 * @since 3.0.2
+	 */
+	default String getOperator() {
 		return toDocument(Aggregation.DEFAULT_CONTEXT).keySet().iterator().next();
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOptions.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOptions.java
index aab74a8a6..fc5928215 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOptions.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOptions.java
@@ -221,11 +221,12 @@ public class AggregationOptions {
 	}
 
 	/**
-	 * @return the {@link ResultOptions} to be used when running the {@link Aggregation}. Never {@literal null}.
-	 * @since 3.0
+	 * @return {@literal true} to skip results when running an aggregation. Useful in combination with {@code $merge} or
+	 *         {@code $out}.
+	 * @since 3.0.2
 	 */
-	public ResultOptions resultOptions() {
-		return resultOptions;
+	public boolean isSkipResults() {
+		return ResultOptions.SKIP.equals(resultOptions);
 	}
 
 	/**
@@ -415,7 +416,7 @@ public class AggregationOptions {
 		 * option allows to execute the aggregation without having the cursor return the operation result.
 		 *
 		 * @return this.
-		 * @since 3.0
+		 * @since 3.0.2
 		 */
 		public Builder skipOutput() {
 
@@ -445,7 +446,7 @@ public class AggregationOptions {
 	/**
 	 * @since 3.0
 	 */
-	public enum ResultOptions {
+	private enum ResultOptions {
 
 		/**
 		 * Just do it!, and do not read the operation result.
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationPipeline.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationPipeline.java
index 2b7ae7d2d..8c4b0ed10 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationPipeline.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationPipeline.java
@@ -26,7 +26,7 @@ import org.springframework.util.Assert;
  * The {@link AggregationPipeline} holds the collection of {@link AggregationOperation aggregation stages}.
  *
  * @author Christoph Strobl
- * @since 3.1
+ * @since 3.0.2
  */
 public class AggregationPipeline {
 
@@ -86,7 +86,7 @@ public class AggregationPipeline {
 			return false;
 		}
 
-		String operator = pipeline.get(pipeline.size() - 1).operator();
+		String operator = pipeline.get(pipeline.size() - 1).getOperator();
 		return operator.equals("$out") || operator.equals("$merge");
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketAutoOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketAutoOperation.java
index 22511adb8..3f2d73347 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketAutoOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketAutoOperation.java
@@ -15,12 +15,11 @@
  */
 package org.springframework.data.mongodb.core.aggregation;
 
+import org.bson.Document;
 import org.springframework.data.mongodb.core.aggregation.BucketAutoOperation.BucketAutoOperationOutputBuilder;
 import org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder;
 import org.springframework.util.Assert;
 
-import org.bson.Document;
-
 /**
  * Encapsulates the aggregation framework {@code $bucketAuto}-operation. <br />
  * Bucket stage is typically used with {@link Aggregation} and {@code $facet}. Categorizes incoming documents into a
@@ -106,11 +105,15 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 
 		options.putAll(super.toDocument(context));
 
-		return new Document(operator(), options);
+		return new Document(getOperator(), options);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$bucketAuto";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperation.java
index 17e4dbc6f..67cdbe2ee 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/BucketOperation.java
@@ -20,21 +20,19 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import org.bson.Document;
 import org.springframework.data.mongodb.core.aggregation.BucketOperation.BucketOperationOutputBuilder;
 import org.springframework.util.Assert;
 
-import org.bson.Document;
-
 /**
  * Encapsulates the aggregation framework {@code $bucket}-operation. <br />
- *
  * Bucket stage is typically used with {@link Aggregation} and {@code $facet}. Categorizes incoming documents into
  * groups, called buckets, based on a specified expression and bucket boundaries. <br />
- *
  * We recommend to use the static factory method {@link Aggregation#bucket(String)} instead of creating instances of
  * this class directly.
  *
- * @see <a href="https://docs.mongodb.org/manual/reference/aggregation/bucket/">https://docs.mongodb.org/manual/reference/aggregation/bucket/</a>
+ * @see <a href=
+ *      "https://docs.mongodb.org/manual/reference/aggregation/bucket/">https://docs.mongodb.org/manual/reference/aggregation/bucket/</a>
  * @see BucketOperationSupport
  * @author Mark Paluch
  * @since 1.10
@@ -103,11 +101,15 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 
 		options.putAll(super.toDocument(context));
 
-		return new Document(operator(), options);
+		return new Document(getOperator(), options);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$bucket";
 	}
 
@@ -209,8 +211,8 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 			extends ExpressionBucketOperationBuilderSupport<BucketOperationOutputBuilder, BucketOperation> {
 
 		/**
-		 * Creates a new {@link ExpressionBucketOperationBuilderSupport} for the given value, {@link BucketOperation}
-		 * and parameters.
+		 * Creates a new {@link ExpressionBucketOperationBuilderSupport} for the given value, {@link BucketOperation} and
+		 * parameters.
 		 *
 		 * @param expression must not be {@literal null}.
 		 * @param operation must not be {@literal null}.
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/CountOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/CountOperation.java
index 03bdf21ca..8ac0d45b6 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/CountOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/CountOperation.java
@@ -49,11 +49,11 @@ public class CountOperation implements FieldsExposingAggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), fieldName);
+		return new Document(getOperator(), fieldName);
 	}
 
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$count";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/DocumentEnhancingOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/DocumentEnhancingOperation.java
index 77a1a064a..0a650dc0d 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/DocumentEnhancingOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/DocumentEnhancingOperation.java
@@ -71,8 +71,12 @@ abstract class DocumentEnhancingOperation implements InheritsFieldsAggregationOp
 	 */
 	protected abstract String mongoOperator();
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return mongoOperator();
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FacetOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FacetOperation.java
index e1a4f9144..77fe14854 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FacetOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FacetOperation.java
@@ -20,12 +20,11 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import org.bson.Document;
 import org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.Output;
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
 import org.springframework.util.Assert;
 
-import org.bson.Document;
-
 /**
  * Encapsulates the aggregation framework {@code $facet}-operation. <br />
  * Facet of {@link AggregationOperation}s to be used in an {@link Aggregation}. Processes multiple
@@ -84,11 +83,15 @@ public class FacetOperation implements FieldsExposingAggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), facets.toDocument(context));
+		return new Document(getOperator(), facets.toDocument(context));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$facet";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java
index b17b90d2f..83468abb1 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java
@@ -16,14 +16,12 @@
 package org.springframework.data.mongodb.core.aggregation;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 import org.bson.Document;
 import org.springframework.data.mongodb.core.query.NearQuery;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.NumberUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -95,25 +93,26 @@ public class GeoNearOperation implements AggregationOperation {
 
 		Document command = context.getMappedObject(nearQuery.toDocument());
 
-		if(command.containsKey("query")) {
+		if (command.containsKey("query")) {
 			command.replace("query", context.getMappedObject(command.get("query", Document.class)));
 		}
 
-		if(command.containsKey("collation")) {
-			command.remove("collation");
-		}
-
+		command.remove("collation");
 		command.put("distanceField", distanceField);
 
 		if (StringUtils.hasText(indexKey)) {
 			command.put("key", indexKey);
 		}
 
-		return new Document(operator(), command);
+		return new Document(getOperator(), command);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$geoNear";
 	}
 
@@ -130,11 +129,11 @@ public class GeoNearOperation implements AggregationOperation {
 		List<Document> stages = new ArrayList<>();
 		stages.add(command);
 
-		if(nearQuery.getSkip() != null && nearQuery.getSkip() > 0){
+		if (nearQuery.getSkip() != null && nearQuery.getSkip() > 0) {
 			stages.add(new Document("$skip", nearQuery.getSkip()));
 		}
 
-		if(limit != null) {
+		if (limit != null) {
 			stages.add(new Document("$limit", limit.longValue()));
 		}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GraphLookupOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GraphLookupOperation.java
index 4afb13177..abf7ff393 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GraphLookupOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GraphLookupOperation.java
@@ -119,11 +119,11 @@ public class GraphLookupOperation implements InheritsFieldsAggregationOperation
 			graphLookup.put("restrictSearchWithMatch", context.getMappedObject(restrictSearchWithMatch.getCriteriaObject()));
 		}
 
-		return new Document(operator(), graphLookup);
+		return new Document(getOperator(), graphLookup);
 	}
 
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$graphLookup";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java
index d4a4a9dd3..8f586fd75 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java
@@ -429,11 +429,15 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 			operationObject.putAll(operation.toDocument(context));
 		}
 
-		return new Document(operator(), operationObject);
+		return new Document(getOperator(), operationObject);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$group";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java
index bc0a0de8e..e41363b23 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java
@@ -49,11 +49,15 @@ public class LimitOperation implements AggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), Long.valueOf(maxElements));
+		return new Document(getOperator(), Long.valueOf(maxElements));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$limit";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LiteralOperators.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LiteralOperators.java
index 64ac1a1d2..062f823e3 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LiteralOperators.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LiteralOperators.java
@@ -76,6 +76,10 @@ public class LiteralOperators {
 			super(value);
 		}
 
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AbstractAggregationExpression#getMongoMethod()
+		 */
 		@Override
 		protected String getMongoMethod() {
 			return "$literal";
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LookupOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LookupOperation.java
index 4f2c89c0d..7be63c33e 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LookupOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LookupOperation.java
@@ -83,11 +83,15 @@ public class LookupOperation implements FieldsExposingAggregationOperation, Inhe
 		lookupObject.append("foreignField", foreignField.getTarget());
 		lookupObject.append("as", as.getTarget());
 
-		return new Document(operator(), lookupObject);
+		return new Document(getOperator(), lookupObject);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$lookup";
 	}
 
@@ -173,8 +177,7 @@ public class LookupOperation implements FieldsExposingAggregationOperation, Inhe
 
 			Assert.hasText(name, "'As' must not be null or empty!");
 			as = new ExposedField(Fields.field(name), true);
-			return new LookupOperation(from, localField, foreignField,
-					as);
+			return new LookupOperation(from, localField, foreignField, as);
 		}
 
 		@Override
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java
index d306077c2..8f2f0aa28 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java
@@ -30,7 +30,8 @@ import org.springframework.util.Assert;
  * @author Thomas Darimont
  * @author Oliver Gierke
  * @since 1.3
- * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/match/">MongoDB Aggregation Framework: $match</a>
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/match/">MongoDB Aggregation Framework:
+ *      $match</a>
  */
 public class MatchOperation implements AggregationOperation {
 
@@ -53,11 +54,15 @@ public class MatchOperation implements AggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), context.getMappedObject(criteriaDefinition.getCriteriaObject()));
+		return new Document(getOperator(), context.getMappedObject(criteriaDefinition.getCriteriaObject()));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$match";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MergeOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MergeOperation.java
index eba2d204b..05e01e4fc 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MergeOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MergeOperation.java
@@ -100,7 +100,7 @@ public class MergeOperation implements FieldsExposingAggregationOperation, Inher
 	public Document toDocument(AggregationOperationContext context) {
 
 		if (isJustCollection()) {
-			return new Document(operator(), into.collection);
+			return new Document(getOperator(), into.collection);
 		}
 
 		Document $merge = new Document();
@@ -122,11 +122,15 @@ public class MergeOperation implements FieldsExposingAggregationOperation, Inher
 			$merge.putAll(whenNotMatched.toDocument(context));
 		}
 
-		return new Document(operator(), $merge);
+		return new Document(getOperator(), $merge);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$merge";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/OutOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/OutOperation.java
index d4c44a1f7..4eaa66966 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/OutOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/OutOperation.java
@@ -16,7 +16,6 @@
 package org.springframework.data.mongodb.core.aggregation;
 
 import org.bson.Document;
-
 import org.springframework.data.mongodb.util.BsonUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -211,11 +210,15 @@ public class OutOperation implements AggregationOperation {
 			$out.append("uniqueKey", uniqueKey);
 		}
 
-		return new Document(operator(), $out);
+		return new Document(getOperator(), $out);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$out";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java
index d0bbcfa06..21278041a 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java
@@ -261,11 +261,15 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 			fieldObject.putAll(projection.toDocument(context));
 		}
 
-		return new Document(operator(), fieldObject);
+		return new Document(getOperator(), fieldObject);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$project";
 	}
 
@@ -1553,7 +1557,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 				final Field aliasedField = Fields.field(alias, this.field.getName());
 				return new OperationProjection(aliasedField, operation, values.toArray()) {
 
-					/* 
+					/*
 					 * (non-Javadoc)
 					 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.ProjectionOperationBuilder.OperationProjection#getField()
 					 */
@@ -1754,7 +1758,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 			this.expression = expression;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 		 */
@@ -1882,7 +1886,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 			this.projections = projections;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 		 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/RedactOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/RedactOperation.java
index 7f27bf77a..3428b64bb 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/RedactOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/RedactOperation.java
@@ -74,11 +74,15 @@ public class RedactOperation implements AggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), condition.toDocument(context));
+		return new Document(getOperator(), condition.toDocument(context));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$redact";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ReplaceRootOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ReplaceRootOperation.java
index 6d53221f9..a63275fee 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ReplaceRootOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ReplaceRootOperation.java
@@ -86,8 +86,12 @@ public class ReplaceRootOperation implements FieldsExposingAggregationOperation
 		return new Document("$replaceRoot", new Document("newRoot", getReplacement().toDocumentExpression(context)));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$replaceRoot";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleOperation.java
index a7c1fe711..b1c3bf4ce 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleOperation.java
@@ -48,11 +48,15 @@ public class SampleOperation implements AggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), new Document("size", this.sampleSize));
+		return new Document(getOperator(), new Document("size", this.sampleSize));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$sample";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SetOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SetOperation.java
index b9f43d5d3..cd06098fe 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SetOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SetOperation.java
@@ -99,6 +99,10 @@ public class SetOperation extends DocumentEnhancingOperation {
 		return new FieldAppender(getValueMap());
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.DocumentEnhancingOperation#mongoOperator()
+	 */
 	@Override
 	protected String mongoOperator() {
 		return "$set";
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java
index 10883b037..2fbbc7209 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java
@@ -28,7 +28,8 @@ import org.springframework.util.Assert;
  * @author Oliver Gierke
  * @author Christoph Strobl
  * @since 1.3
- * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/skip/">MongoDB Aggregation Framework: $skip</a>
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/skip/">MongoDB Aggregation Framework:
+ *      $skip</a>
  */
 public class SkipOperation implements AggregationOperation {
 
@@ -51,11 +52,15 @@ public class SkipOperation implements AggregationOperation {
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
-		return new Document(operator(), skipCount);
+		return new Document(getOperator(), skipCount);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$skip";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortByCountOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortByCountOperation.java
index f26e60eac..a631b0862 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortByCountOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortByCountOperation.java
@@ -67,19 +67,23 @@ public class SortByCountOperation implements AggregationOperation {
 		this.groupByField = null;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 	 */
 	@Override
 	public Document toDocument(AggregationOperationContext context) {
 
-		return new Document(operator(), groupByExpression == null ? context.getReference(groupByField).toString()
+		return new Document(getOperator(), groupByExpression == null ? context.getReference(groupByField).toString()
 				: groupByExpression.toDocument(context));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$sortByCount";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java
index cfd3f8a3e..5b5cce458 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java
@@ -33,7 +33,8 @@ import org.springframework.util.Assert;
  * @author Christoph Strobl
  * @author Mark Paluch
  * @since 1.3
- * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/sort/">MongoDB Aggregation Framework: $sort</a>
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/sort/">MongoDB Aggregation Framework:
+ *      $sort</a>
  */
 public class SortOperation implements AggregationOperation {
 
@@ -74,11 +75,15 @@ public class SortOperation implements AggregationOperation {
 			object.put(reference.getRaw(), order.isAscending() ? 1 : -1);
 		}
 
-		return new Document(operator(), object);
+		return new Document(getOperator(), object);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$sort";
 	}
 }
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnsetOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnsetOperation.java
index 89dc79ea8..b42cef2a6 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnsetOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnsetOperation.java
@@ -40,7 +40,7 @@ public class UnsetOperation implements InheritsFieldsAggregationOperation {
 
 	/**
 	 * Create new instance of {@link UnsetOperation}.
-	 * 
+	 *
 	 * @param fields must not be {@literal null}.
 	 */
 	public UnsetOperation(Collection<Object> fields) {
@@ -117,15 +117,19 @@ public class UnsetOperation implements InheritsFieldsAggregationOperation {
 	public Document toDocument(AggregationOperationContext context) {
 
 		if (fields.size() == 1) {
-			return new Document(operator(), computeFieldName(fields.iterator().next(), context));
+			return new Document(getOperator(), computeFieldName(fields.iterator().next(), context));
 		}
 
-		return new Document(operator(),
+		return new Document(getOperator(),
 				fields.stream().map(it -> computeFieldName(it, context)).collect(Collectors.toList()));
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$unset";
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java
index 492afd244..11e4dcaea 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java
@@ -31,7 +31,8 @@ import org.springframework.util.Assert;
  * @author Mark Paluch
  * @author Christoph Strobl
  * @since 1.3
- * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/unwind/">MongoDB Aggregation Framework: $unwind</a>
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/unwind/">MongoDB Aggregation Framework:
+ *      $unwind</a>
  */
 public class UnwindOperation
 		implements AggregationOperation, FieldsExposingAggregationOperation.InheritsFieldsAggregationOperation {
@@ -94,7 +95,7 @@ public class UnwindOperation
 		String path = context.getReference(field).toString();
 
 		if (!preserveNullAndEmptyArrays && arrayIndex == null) {
-			return new Document(operator(), path);
+			return new Document(getOperator(), path);
 		}
 
 		Document unwindArgs = new Document();
@@ -104,11 +105,15 @@ public class UnwindOperation
 		}
 		unwindArgs.put("preserveNullAndEmptyArrays", preserveNullAndEmptyArrays);
 
-		return new Document(operator(), unwindArgs);
+		return new Document(getOperator(), unwindArgs);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
 	@Override
-	public String operator() {
+	public String getOperator() {
 		return "$unwind";
 	}
 
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
index 6be58d731..abc994a05 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
@@ -99,17 +99,17 @@ public class AggregationTests {
 	private static boolean initialized = false;
 
 	@Template //
-	static MongoTestTemplate mongoTemplate;
+	private static MongoTestTemplate mongoTemplate;
 
 	@BeforeEach
-	public void setUp() {
+	void setUp() {
 
 		cleanDb();
 		initSampleDataIfNecessary();
 	}
 
 	@AfterEach
-	public void cleanUp() {
+	void cleanUp() {
 		cleanDb();
 	}
 
@@ -167,25 +167,25 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldHandleMissingInputCollection() {
+	void shouldHandleMissingInputCollection() {
 		assertThatIllegalArgumentException()
 				.isThrownBy(() -> mongoTemplate.aggregate(newAggregation(), (String) null, TagCount.class));
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldHandleMissingAggregationPipeline() {
+	void shouldHandleMissingAggregationPipeline() {
 		assertThatIllegalArgumentException()
 				.isThrownBy(() -> mongoTemplate.aggregate(null, INPUT_COLLECTION, TagCount.class));
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldHandleMissingEntityClass() {
+	void shouldHandleMissingEntityClass() {
 		assertThatIllegalArgumentException()
 				.isThrownBy(() -> mongoTemplate.aggregate(newAggregation(), INPUT_COLLECTION, null));
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldAggregate() {
+	void shouldAggregate() {
 
 		createTagDocuments();
 
@@ -214,7 +214,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void shouldAggregateAndStream() {
+	void shouldAggregateAndStream() {
 
 		createTagDocuments();
 
@@ -243,7 +243,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldAggregateEmptyCollection() {
+	void shouldAggregateEmptyCollection() {
 
 		Aggregation aggregation = newAggregation(//
 				project("tags"), //
@@ -266,7 +266,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void shouldAggregateEmptyCollectionAndStream() {
+	void shouldAggregateEmptyCollectionAndStream() {
 
 		Aggregation aggregation = newAggregation(//
 				project("tags"), //
@@ -289,7 +289,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1391
-	public void shouldUnwindWithIndex() {
+	void shouldUnwindWithIndex() {
 
 		MongoCollection<Document> coll = mongoTemplate.getCollection(INPUT_COLLECTION);
 
@@ -315,7 +315,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1391
-	public void shouldUnwindPreserveEmpty() {
+	void shouldUnwindPreserveEmpty() {
 
 		MongoCollection<Document> coll = mongoTemplate.getCollection(INPUT_COLLECTION);
 
@@ -341,7 +341,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void shouldDetectResultMismatch() {
+	void shouldDetectResultMismatch() {
 
 		createTagDocuments();
 
@@ -366,7 +366,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void shouldDetectResultMismatchWhileStreaming() {
+	void shouldDetectResultMismatchWhileStreaming() {
 
 		createTagDocuments();
 
@@ -391,7 +391,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void complexAggregationFrameworkUsageLargestAndSmallestCitiesByState() {
+	void complexAggregationFrameworkUsageLargestAndSmallestCitiesByState() {
 		/*
 		 //complex mongodb aggregation framework example from https://docs.mongodb.org/manual/tutorial/aggregation-examples/#largest-and-smallest-cities-by-state
 		db.zipInfo.aggregate(
@@ -499,11 +499,11 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void findStatesWithPopulationOver10MillionAggregationExample() {
+	void findStatesWithPopulationOver10MillionAggregationExample() {
 		/*
 		 //complex mongodb aggregation framework example from
 		 https://docs.mongodb.org/manual/tutorial/aggregation-examples/#largest-and-smallest-cities-by-state
-		
+
 		 db.zipcodes.aggregate(
 			 	{
 				   $group: {
@@ -549,7 +549,7 @@ public class AggregationTests {
 	 *      Framework: $cond</a>
 	 */
 	@Test // DATAMONGO-861
-	public void aggregationUsingConditionalProjectionToCalculateDiscount() {
+	void aggregationUsingConditionalProjectionToCalculateDiscount() {
 
 		/*
 		db.inventory.aggregate(
@@ -602,7 +602,7 @@ public class AggregationTests {
 	 *      Framework: $ifNull</a>
 	 */
 	@Test // DATAMONGO-861
-	public void aggregationUsingIfNullToProjectSaneDefaults() {
+	void aggregationUsingIfNullToProjectSaneDefaults() {
 
 		/*
 		db.inventory.aggregate(
@@ -642,7 +642,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-861
-	public void aggregationUsingConditionalProjection() {
+	void aggregationUsingConditionalProjection() {
 
 		TypedAggregation<ZipInfo> aggregation = newAggregation(ZipInfo.class, //
 				project() //
@@ -664,7 +664,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-861
-	public void aggregationUsingNestedConditionalProjection() {
+	void aggregationUsingNestedConditionalProjection() {
 
 		TypedAggregation<ZipInfo> aggregation = newAggregation(ZipInfo.class, //
 				project() //
@@ -687,7 +687,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-861
-	public void aggregationUsingIfNullProjection() {
+	void aggregationUsingIfNullProjection() {
 
 		mongoTemplate.insert(new LineItem("id", "caption", 0));
 		mongoTemplate.insert(new LineItem("idonly", null, 0));
@@ -711,7 +711,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-861
-	public void aggregationUsingIfNullReplaceWithFieldReferenceProjection() {
+	void aggregationUsingIfNullReplaceWithFieldReferenceProjection() {
 
 		mongoTemplate.insert(new LineItem("id", "caption", 0));
 		mongoTemplate.insert(new LineItem("idonly", null, 0));
@@ -735,7 +735,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-861
-	public void shouldAllowGroupingUsingConditionalExpressions() {
+	void shouldAllowGroupingUsingConditionalExpressions() {
 
 		mongoTemplate.dropCollection(CarPerson.class);
 
@@ -779,7 +779,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1784, DATAMONGO-2264
-	public void shouldAllowSumUsingConditionalExpressions() {
+	void shouldAllowSumUsingConditionalExpressions() {
 
 		mongoTemplate.dropCollection(CarPerson.class);
 
@@ -827,7 +827,7 @@ public class AggregationTests {
 	 *      the Five Most Common “Likes”</a>
 	 */
 	@Test // DATAMONGO-586
-	public void returnFiveMostCommonLikesAggregationFrameworkExample() {
+	void returnFiveMostCommonLikesAggregationFrameworkExample() {
 
 		createUserWithLikesDocuments();
 
@@ -848,7 +848,7 @@ public class AggregationTests {
 		assertLikeStats(result.getMappedResults().get(4), "e", 3);
 	}
 
-	protected TypedAggregation<UserWithLikes> createUsersWithCommonLikesAggregation() {
+	TypedAggregation<UserWithLikes> createUsersWithCommonLikesAggregation() {
 		return newAggregation(UserWithLikes.class, //
 				unwind("likes"), //
 				group("likes").count().as("number"), //
@@ -859,7 +859,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-586
-	public void arithmenticOperatorsInProjectionExample() {
+	void arithmenticOperatorsInProjectionExample() {
 
 		Product product = new Product("P1", "A", 1.99, 3, 0.05, 0.19);
 		mongoTemplate.insert(product);
@@ -902,7 +902,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-774
-	public void expressionsInProjectionExample() {
+	void expressionsInProjectionExample() {
 
 		Product product = new Product("P1", "A", 1.99, 3, 0.05, 0.19);
 		mongoTemplate.insert(product);
@@ -934,7 +934,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-774
-	public void stringExpressionsInProjectionExample() {
+	void stringExpressionsInProjectionExample() {
 
 		Product product = new Product("P1", "A", 1.99, 3, 0.05, 0.19);
 		mongoTemplate.insert(product);
@@ -954,7 +954,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-774
-	public void expressionsInProjectionExampleShowcase() {
+	void expressionsInProjectionExampleShowcase() {
 
 		Product product = new Product("P1", "A", 1.99, 3, 0.05, 0.19);
 		mongoTemplate.insert(product);
@@ -983,7 +983,7 @@ public class AggregationTests {
 	 *      Data MongoDB - Aggregation Framework - invalid reference in group Operation</a>
 	 */
 	@Test // DATAMONGO-753
-	public void allowsNestedFieldReferencesAsGroupIdsInGroupExpressions() {
+	void allowsNestedFieldReferencesAsGroupIdsInGroupExpressions() {
 
 		mongoTemplate.insert(new DATAMONGO753().withPDs(new PD("A", 1), new PD("B", 1), new PD("C", 1)));
 		mongoTemplate.insert(new DATAMONGO753().withPDs(new PD("B", 1), new PD("B", 1), new PD("C", 1)));
@@ -1013,7 +1013,7 @@ public class AggregationTests {
 	 *      Data MongoDB - Aggregation Framework - invalid reference in group Operation</a>
 	 */
 	@Test // DATAMONGO-753
-	public void aliasesNestedFieldInProjectionImmediately() {
+	void aliasesNestedFieldInProjectionImmediately() {
 
 		mongoTemplate.insert(new DATAMONGO753().withPDs(new PD("A", 1), new PD("B", 1), new PD("C", 1)));
 		mongoTemplate.insert(new DATAMONGO753().withPDs(new PD("B", 1), new PD("B", 1), new PD("C", 1)));
@@ -1032,7 +1032,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-774
-	public void shouldPerformDateProjectionOperatorsCorrectly() throws ParseException {
+	void shouldPerformDateProjectionOperatorsCorrectly() throws ParseException {
 
 		Data data = new Data();
 		data.stringValue = "ABC";
@@ -1058,7 +1058,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-774
-	public void shouldPerformStringProjectionOperatorsCorrectly() throws ParseException {
+	void shouldPerformStringProjectionOperatorsCorrectly() throws ParseException {
 
 		Data data = new Data();
 		data.dateValue = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss.SSSZ").parse("29.08.1983 12:34:56.789+0000");
@@ -1094,7 +1094,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1550
-	public void shouldPerformReplaceRootOperatorCorrectly() throws ParseException {
+	void shouldPerformReplaceRootOperatorCorrectly() throws ParseException {
 
 		Data data = new Data();
 		DataItem dataItem = new DataItem();
@@ -1115,7 +1115,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-788, DATAMONGO-2264
-	public void referencesToGroupIdsShouldBeRenderedProperly() {
+	void referencesToGroupIdsShouldBeRenderedProperly() {
 
 		mongoTemplate.insert(new DATAMONGO788(1, 1));
 		mongoTemplate.insert(new DATAMONGO788(1, 1));
@@ -1142,7 +1142,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-806
-	public void shouldAllowGroupByIdFields() {
+	void shouldAllowGroupByIdFields() {
 
 		mongoTemplate.dropCollection(User.class);
 
@@ -1173,7 +1173,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-840
-	public void shouldAggregateOrderDataToAnInvoice() {
+	void shouldAggregateOrderDataToAnInvoice() {
 
 		mongoTemplate.dropCollection(Order.class);
 
@@ -1210,7 +1210,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-924
-	public void shouldAllowGroupingByAliasedFieldDefinedInFormerAggregationStage() {
+	void shouldAllowGroupingByAliasedFieldDefinedInFormerAggregationStage() {
 
 		mongoTemplate.dropCollection(CarPerson.class);
 
@@ -1241,7 +1241,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-960
-	public void returnFiveMostCommonLikesAggregationFrameworkExampleWithSortOnDiskOptionEnabled() {
+	void returnFiveMostCommonLikesAggregationFrameworkExampleWithSortOnDiskOptionEnabled() {
 
 		createUserWithLikesDocuments();
 
@@ -1264,7 +1264,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void returnFiveMostCommonLikesAggregationFrameworkExampleWithSortOnDiskOptionEnabledWhileStreaming() {
+	void returnFiveMostCommonLikesAggregationFrameworkExampleWithSortOnDiskOptionEnabledWhileStreaming() {
 
 		createUserWithLikesDocuments();
 
@@ -1290,7 +1290,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-960
-	public void returnFiveMostCommonLikesShouldReturnStageExecutionInformationWithExplainOptionEnabled() {
+	void returnFiveMostCommonLikesShouldReturnStageExecutionInformationWithExplainOptionEnabled() {
 
 		createUserWithLikesDocuments();
 
@@ -1308,7 +1308,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-954, DATAMONGO-2264
-	public void shouldSupportReturningCurrentAggregationRoot() {
+	void shouldSupportReturningCurrentAggregationRoot() {
 
 		mongoTemplate.save(new Person("p1_first", "p1_last", 25));
 		mongoTemplate.save(new Person("p2_first", "p2_last", 32));
@@ -1333,7 +1333,7 @@ public class AggregationTests {
 	 * {@link https://stackoverflow.com/questions/24185987/using-root-inside-spring-data-mongodb-for-retrieving-whole-document}
 	 */
 	@Test // DATAMONGO-954, DATAMONGO-2264
-	public void shouldSupportReturningCurrentAggregationRootInReference() {
+	void shouldSupportReturningCurrentAggregationRootInReference() {
 
 		mongoTemplate.save(new Reservation("0123", "42", 100));
 		mongoTemplate.save(new Reservation("0360", "43", 200));
@@ -1352,7 +1352,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1549
-	public void shouldApplyCountCorrectly() {
+	void shouldApplyCountCorrectly() {
 
 		mongoTemplate.save(new Reservation("0123", "42", 100));
 		mongoTemplate.save(new Reservation("0360", "43", 200));
@@ -1371,7 +1371,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-975
-	public void shouldRetrieveDateTimeFragementsCorrectly() throws Exception {
+	void shouldRetrieveDateTimeFragementsCorrectly() throws Exception {
 
 		mongoTemplate.dropCollection(ObjectWithDate.class);
 
@@ -1424,7 +1424,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1127
-	public void shouldSupportGeoNearQueriesForAggregationWithDistanceField() {
+	void shouldSupportGeoNearQueriesForAggregationWithDistanceField() {
 
 		mongoTemplate.insertAll(Arrays.asList(TestEntities.geolocation().pennStation(),
 				TestEntities.geolocation().tenGenOffice(), TestEntities.geolocation().flatironBuilding()));
@@ -1444,7 +1444,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1348
-	public void shouldSupportGeoJsonInGeoNearQueriesForAggregationWithDistanceField() {
+	void shouldSupportGeoJsonInGeoNearQueriesForAggregationWithDistanceField() {
 
 		mongoTemplate.insert(new Venue("Penn Station", -73.99408, 40.75057));
 		mongoTemplate.insert(new Venue("10gen Office", -73.99171, 40.738868));
@@ -1466,7 +1466,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1348
-	public void shouldSupportGeoJsonInGeoNearQueriesForAggregationWithDistanceFieldInMiles() {
+	void shouldSupportGeoJsonInGeoNearQueriesForAggregationWithDistanceFieldInMiles() {
 
 		mongoTemplate.insert(new Venue("Penn Station", -73.99408, 40.75057));
 		mongoTemplate.insert(new Venue("10gen Office", -73.99171, 40.738868));
@@ -1489,7 +1489,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1133
-	public void shouldHonorFieldAliasesForFieldReferences() {
+	void shouldHonorFieldAliasesForFieldReferences() {
 
 		mongoTemplate.insert(new MeterData("m1", "counter1", 42));
 		mongoTemplate.insert(new MeterData("m1", "counter1", 13));
@@ -1509,7 +1509,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1326
-	public void shouldLookupPeopleCorectly() {
+	void shouldLookupPeopleCorectly() {
 
 		createUsersWithReferencedPersons();
 
@@ -1528,7 +1528,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1326
-	public void shouldGroupByAndLookupPeopleCorectly() {
+	void shouldGroupByAndLookupPeopleCorectly() {
 
 		createUsersWithReferencedPersons();
 
@@ -1549,7 +1549,7 @@ public class AggregationTests {
 
 	@Test // DATAMONGO-1418, DATAMONGO-1824
 	@MongoVersion(asOf = "2.6")
-	public void shouldCreateOutputCollection() {
+	void shouldCreateOutputCollection() {
 
 		createPersonDocuments();
 
@@ -1573,7 +1573,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void shouldCreateOutputCollectionWhileStreaming() {
+	void shouldCreateOutputCollectionWhileStreaming() {
 
 		createPersonDocuments();
 
@@ -1595,7 +1595,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1637
-	public void shouldReturnDocumentsWithOutputCollectionWhileStreaming() {
+	void shouldReturnDocumentsWithOutputCollectionWhileStreaming() {
 
 		createPersonDocuments();
 
@@ -1626,7 +1626,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1418, DATAMONGO-2536
-	public void outShouldOutBeTheLastOperation() {
+	void outShouldOutBeTheLastOperation() {
 		assertThatIllegalArgumentException().isThrownBy(() -> newAggregation(match(new Criteria()), //
 				group("field1").count().as("totalCount"), //
 				out("collection1"), //
@@ -1634,7 +1634,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1325
-	public void shouldApplySampleCorrectly() {
+	void shouldApplySampleCorrectly() {
 
 		createUserWithLikesDocuments();
 
@@ -1651,7 +1651,7 @@ public class AggregationTests {
 
 	@Test // DATAMONGO-1457
 	@MongoVersion(asOf = "3.2")
-	public void sliceShouldBeAppliedCorrectly() {
+	void sliceShouldBeAppliedCorrectly() {
 
 		createUserWithLikesDocuments();
 
@@ -1667,7 +1667,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1491
-	public void filterShouldBeAppliedCorrectly() {
+	void filterShouldBeAppliedCorrectly() {
 
 		Item item43 = Item.builder().itemId("43").quantity(2).price(2L).build();
 		Item item2 = Item.builder().itemId("2").quantity(1).price(240L).build();
@@ -1697,7 +1697,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1538
-	public void letShouldBeAppliedCorrectly() {
+	void letShouldBeAppliedCorrectly() {
 
 		Sales2 sales1 = Sales2.builder().id("1").price(10).tax(0.5F).applyDiscount(true).build();
 		Sales2 sales2 = Sales2.builder().id("2").price(10).tax(0.25F).applyDiscount(false).build();
@@ -1721,7 +1721,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1551, DATAMONGO-2264
-	public void graphLookupShouldBeAppliedCorrectly() {
+	void graphLookupShouldBeAppliedCorrectly() {
 
 		Employee em1 = Employee.builder().id(1).name("Dev").build();
 		Employee em2 = Employee.builder().id(2).name("Eliot").reportsTo("Dev").build();
@@ -1753,7 +1753,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1552
-	public void bucketShouldCollectDocumentsIntoABucket() {
+	void bucketShouldCollectDocumentsIntoABucket() {
 
 		Art a1 = Art.builder().id(1).title("The Pillars of Society").artist("Grosz").year(1926).price(199.99).build();
 		Art a2 = Art.builder().id(2).title("Melancholy III").artist("Munch").year(1902).price(280.00).build();
@@ -1787,7 +1787,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1552, DATAMONGO-2437
-	public void bucketAutoShouldCollectDocumentsIntoABucket() {
+	void bucketAutoShouldCollectDocumentsIntoABucket() {
 
 		Art a1 = Art.builder().id(1).title("The Pillars of Society").artist("Grosz").year(1926).price(199.99).build();
 		Art a2 = Art.builder().id(2).title("Melancholy III").artist("Munch").year(1902).price(280.00).build();
@@ -1820,7 +1820,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1552
-	public void facetShouldCreateFacets() {
+	void facetShouldCreateFacets() {
 
 		Art a1 = Art.builder().id(1).title("The Pillars of Society").artist("Grosz").year(1926).price(199.99).build();
 		Art a2 = Art.builder().id(2).title("Melancholy III").artist("Munch").year(1902).price(280.00).build();
@@ -1863,7 +1863,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1986
-	public void runMatchOperationCriteriaThroughQueryMapperForTypedAggregation() {
+	void runMatchOperationCriteriaThroughQueryMapperForTypedAggregation() {
 
 		mongoTemplate.insertAll(TestEntities.geolocation().newYork());
 
@@ -1878,7 +1878,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-1986
-	public void runMatchOperationCriteriaThroughQueryMapperForUntypedAggregation() {
+	void runMatchOperationCriteriaThroughQueryMapperForUntypedAggregation() {
 
 		mongoTemplate.insertAll(TestEntities.geolocation().newYork());
 
@@ -1893,7 +1893,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-2437
-	public void shouldReadComplexIdValueCorrectly() {
+	void shouldReadComplexIdValueCorrectly() {
 
 		WithComplexId source = new WithComplexId();
 		source.id = new ComplexId();
@@ -1908,7 +1908,7 @@ public class AggregationTests {
 	}
 
 	@Test // DATAMONGO-2536
-	public void skipOutputDoesNotReadBackAggregationResults() {
+	void skipOutputDoesNotReadBackAggregationResults() {
 
 		createTagDocuments();
 
@@ -2021,7 +2021,7 @@ public class AggregationTests {
 		String pDch;
 		@org.springframework.data.mongodb.core.mapping.Field("alias") int up;
 
-		public PD(String pDch, int up) {
+		PD(String pDch, int up) {
 			this.pDch = pDch;
 			this.up = up;
 		}
@@ -2036,7 +2036,7 @@ public class AggregationTests {
 
 		public DATAMONGO788() {}
 
-		public DATAMONGO788(int x, int y) {
+		DATAMONGO788(int x, int y) {
 			this.x = x;
 			this.xField = x;
 			this.y = y;
@@ -2052,7 +2052,7 @@ public class AggregationTests {
 
 		public User() {}
 
-		public User(String id, PushMessage... msgs) {
+		User(String id, PushMessage... msgs) {
 			this.id = id;
 			this.msgs = Arrays.asList(msgs);
 		}
@@ -2067,7 +2067,7 @@ public class AggregationTests {
 
 		public PushMessage() {}
 
-		public PushMessage(String id, String content, Date createDate) {
+		PushMessage(String id, String content, Date createDate) {
 			this.id = id;
 			this.content = content;
 			this.createDate = createDate;
@@ -2082,7 +2082,7 @@ public class AggregationTests {
 		private String lastName;
 		private Descriptors descriptors;
 
-		public CarPerson(String firstname, String lastname, Entry... entries) {
+		CarPerson(String firstname, String lastname, Entry... entries) {
 			this.firstName = firstname;
 			this.lastName = lastname;
 
@@ -2102,7 +2102,7 @@ public class AggregationTests {
 
 		private List<Entry> entries = new ArrayList<AggregationTests.CarDescriptor.Entry>();
 
-		public CarDescriptor(Entry... entries) {
+		CarDescriptor(Entry... entries) {
 
 			for (Entry entry : entries) {
 				this.entries.add(entry);
@@ -2118,7 +2118,7 @@ public class AggregationTests {
 
 			public Entry() {}
 
-			public Entry(String make, String model, int year) {
+			Entry(String make, String model, int year) {
 				this.make = make;
 				this.model = model;
 				this.year = year;
@@ -2134,7 +2134,7 @@ public class AggregationTests {
 
 		public Reservation() {}
 
-		public Reservation(String hotelCode, String confirmationNumber, int timestamp) {
+		Reservation(String hotelCode, String confirmationNumber, int timestamp) {
 			this.hotelCode = hotelCode;
 			this.confirmationNumber = confirmationNumber;
 			this.timestamp = timestamp;
@@ -2145,7 +2145,7 @@ public class AggregationTests {
 
 		Date dateValue;
 
-		public ObjectWithDate(Date dateValue) {
+		ObjectWithDate(Date dateValue) {
 			this.dateValue = dateValue;
 		}
 	}
@@ -2161,14 +2161,14 @@ public class AggregationTests {
 
 		public InventoryItem() {}
 
-		public InventoryItem(int id, String item, int qty) {
+		InventoryItem(int id, String item, int qty) {
 
 			this.id = id;
 			this.item = item;
 			this.qty = qty;
 		}
 
-		public InventoryItem(int id, String item, String description, int qty) {
+		InventoryItem(int id, String item, String description, int qty) {
 
 			this.id = id;
 			this.item = item;
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/ReactiveAggregationTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/ReactiveAggregationTests.java
index 61d3834b4..9051c27b2 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/ReactiveAggregationTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/ReactiveAggregationTests.java
@@ -181,5 +181,4 @@ public class ReactiveAggregationTests {
 		reactiveMongoTemplate.aggregate(agg, Document.class).as(StepVerifier::create).verifyComplete();
 	}
 
-
 }