Introduce dedicated Collation annotation.

The Collation annotation mainly serves as a meta annotation that allows common access to retrieving collation values for annotated queries, aggregations, etc.

Original Pull Request: #4131

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/annotation/Collation.java

@@ -0,0 +1,44 @@
+/*
+ * 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.data.mongodb.core.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * {@link Collation} allows to define the rules used for language-specific string comparison.
+ *
+ * @see <a href="https://www.mongodb.com/docs/manual/reference/collation/">https://www.mongodb.com/docs/manual/reference/collation/</a>
+ * @author Christoph Strobl
+ * @since 4.0
+ */
+@Inherited
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE, ElementType.METHOD })
+public @interface Collation {
+
+	/**
+	 * The actual collation definition in JSON format or a
+	 * {@link org.springframework.expression.spel.standard.SpelExpression template expression} resolving to either a JSON
+	 * String or a {@link org.bson.Document}. The keys of the JSON document are configuration options for the collation.
+	 *
+	 * @return an empty {@link String} by default.
+	 */
+	String value() default "";
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/annotation/package-info.java

@@ -0,0 +1,6 @@
+/**
+ * Core Spring Data MongoDB annotations not limited to a special use case (like Query,...).
+ */
+@org.springframework.lang.NonNullApi
+package org.springframework.data.mongodb.core.annotation;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/CompoundIndex.java

@@ -22,7 +22,10 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
+import org.springframework.data.mongodb.core.annotation.Collation;
 import org.springframework.data.mongodb.core.mapping.Document;
+
 /**
  * Mark a class to use compound indexes. <br />
  * <p>
@@ -49,6 +52,7 @@ import org.springframework.data.mongodb.core.mapping.Document;
  * @author Dave Perryman
  * @author Stefan Tirea
  */
+@Collation
 @Target({ ElementType.TYPE })
 @Documented
 @Repeatable(CompoundIndexes.class)
@@ -181,5 +185,6 @@ public @interface CompoundIndex {
 	 *      "https://www.mongodb.com/docs/manual/reference/collation/">https://www.mongodb.com/docs/manual/reference/collation/</a>
 	 * @since 4.0
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Indexed.java

@@ -20,7 +20,10 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
+import org.springframework.data.mongodb.core.annotation.Collation;
 import org.springframework.data.mongodb.core.mapping.Document;
+
 /**
  * Mark a field to be indexed using MongoDB's indexing feature.
  *
@@ -34,6 +37,7 @@ import org.springframework.data.mongodb.core.mapping.Document;
  * @author Mark Paluch
  * @author Stefan Tirea
  */
+@Collation
 @Target({ ElementType.ANNOTATION_TYPE, ElementType.FIELD })
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Indexed {
@@ -188,5 +192,6 @@ public @interface Indexed {
 	 * @see <a href="https://www.mongodb.com/docs/manual/reference/collation/">https://www.mongodb.com/docs/manual/reference/collation/</a>
 	 * @since 4.0
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexResolver.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.index;
 
+import java.lang.annotation.Annotation;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -23,13 +24,15 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
+import org.springframework.core.annotation.MergedAnnotation;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.mapping.Association;
@@ -50,12 +53,10 @@ import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.data.mongodb.core.query.Collation;
 import org.springframework.data.mongodb.util.BsonUtils;
 import org.springframework.data.mongodb.util.DotPath;
+import org.springframework.data.mongodb.util.spel.ExpressionUtils;
 import org.springframework.data.spel.EvaluationContextProvider;
 import org.springframework.data.util.TypeInformation;
 import org.springframework.expression.EvaluationContext;
-import org.springframework.expression.Expression;
-import org.springframework.expression.ParserContext;
-import org.springframework.expression.common.LiteralExpression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -454,10 +455,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 			indexDefinition.partial(evaluatePartialFilter(index.partialFilter(), entity));
 		}
 
-		if (StringUtils.hasText(index.collation())) {
+		indexDefinition.collation(resolveCollation(index, entity));
-			indexDefinition.collation(evaluateCollation(index.collation(), entity));
-		}
-
 		return new IndexDefinitionHolder(dotPath, indexDefinition, collection);
 	}
 
@@ -478,12 +476,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 			indexDefinition.partial(evaluatePartialFilter(index.partialFilter(), entity));
 		}
 
-		if (StringUtils.hasText(index.collation())) {
+		indexDefinition.collation(resolveCollation(index, entity));
-			indexDefinition.collation(evaluateCollation(index.collation(), entity));
-		} else if (entity != null && entity.hasCollation()) {
-			indexDefinition.collation(entity.getCollation());
-		}
-
 		return new IndexDefinitionHolder(dotPath, indexDefinition, collection);
 	}
 
@@ -498,7 +491,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 			return new org.bson.Document(dotPath, 1);
 		}
 
-		Object keyDefToUse = evaluate(keyDefinitionString, getEvaluationContextForProperty(entity));
+		Object keyDefToUse = ExpressionUtils.evaluate(keyDefinitionString, () -> getEvaluationContextForProperty(entity));
 
 		org.bson.Document dbo = (keyDefToUse instanceof org.bson.Document) ? (org.bson.Document) keyDefToUse
 				: org.bson.Document.parse(ObjectUtils.nullSafeToString(keyDefToUse));
@@ -567,7 +560,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 			}
 
 			Duration timeout = computeIndexTimeout(index.expireAfter(),
-					getEvaluationContextForProperty(persistentProperty.getOwner()));
+					() -> getEvaluationContextForProperty(persistentProperty.getOwner()));
 			if (!timeout.isZero() && !timeout.isNegative()) {
 				indexDefinition.expire(timeout);
 			}
@@ -577,16 +570,13 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 			indexDefinition.partial(evaluatePartialFilter(index.partialFilter(), persistentProperty.getOwner()));
 		}
 
-		if (StringUtils.hasText(index.collation())) {
+		indexDefinition.collation(resolveCollation(index, persistentProperty.getOwner()));
-			indexDefinition.collation(evaluateCollation(index.collation(), persistentProperty.getOwner()));
-		}
-
 		return new IndexDefinitionHolder(dotPath, indexDefinition, collection);
 	}
 
 	private PartialIndexFilter evaluatePartialFilter(String filterExpression, PersistentEntity<?, ?> entity) {
 
-		Object result = evaluate(filterExpression, getEvaluationContextForProperty(entity));
+		Object result = ExpressionUtils.evaluate(filterExpression, () -> getEvaluationContextForProperty(entity));
 
 		if (result instanceof org.bson.Document) {
 			return PartialIndexFilter.of((org.bson.Document) result);
@@ -597,7 +587,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 
 	private org.bson.Document evaluateWildcardProjection(String projectionExpression, PersistentEntity<?, ?> entity) {
 
-		Object result = evaluate(projectionExpression, getEvaluationContextForProperty(entity));
+		Object result = ExpressionUtils.evaluate(projectionExpression, () -> getEvaluationContextForProperty(entity));
 
 		if (result instanceof org.bson.Document) {
 			return (org.bson.Document) result;
@@ -608,7 +598,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 
 	private Collation evaluateCollation(String collationExpression, PersistentEntity<?, ?> entity) {
 
-		Object result = evaluate(collationExpression, getEvaluationContextForProperty(entity));
+		Object result = ExpressionUtils.evaluate(collationExpression, () -> getEvaluationContextForProperty(entity));
 		if (result instanceof org.bson.Document) {
 			return Collation.from((org.bson.Document) result);
 		}
@@ -618,6 +608,9 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 		if (result instanceof String) {
 			return Collation.parse(result.toString());
 		}
+		if (result instanceof Map) {
+			return Collation.from(new org.bson.Document((Map<String, ?>) result));
+		}
 		throw new IllegalStateException("Cannot parse collation " + result);
 
 	}
@@ -726,7 +719,7 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 		String nameToUse = "";
 		if (StringUtils.hasText(indexName)) {
 
-			Object result = evaluate(indexName, getEvaluationContextForProperty(entity));
+			Object result = ExpressionUtils.evaluate(indexName, () -> getEvaluationContextForProperty(entity));
 
 			if (result != null) {
 				nameToUse = ObjectUtils.nullSafeToString(result);
@@ -787,9 +780,9 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 	 * @since 2.2
 	 * @throws IllegalArgumentException for invalid duration values.
 	 */
-	private static Duration computeIndexTimeout(String timeoutValue, EvaluationContext evaluationContext) {
+	private static Duration computeIndexTimeout(String timeoutValue, Supplier<EvaluationContext> evaluationContext) {
 
-		Object evaluatedTimeout = evaluate(timeoutValue, evaluationContext);
+		Object evaluatedTimeout = ExpressionUtils.evaluate(timeoutValue, evaluationContext);
 
 		if (evaluatedTimeout == null) {
 			return Duration.ZERO;
@@ -808,15 +801,25 @@ public class MongoPersistentEntityIndexResolver implements IndexResolver {
 		return DurationStyle.detectAndParse(val);
 	}
 
+	/**
+	 * Resolve the "collation" attribute from a given {@link Annotation} if present.
+	 *
+	 * @param annotation
+	 * @param entity
+	 * @return the collation present on either the annotation or the entity as a fallback. Might be {@literal null}.
+	 * @since 4.0
+	 */
 	@Nullable
-	private static Object evaluate(String value, EvaluationContext evaluationContext) {
+	private Collation resolveCollation(Annotation annotation, @Nullable PersistentEntity<?, ?> entity) {
+		return MergedAnnotation.from(annotation).getValue("collation", String.class).filter(StringUtils::hasText)
+				.map(it -> evaluateCollation(it, entity)).orElseGet(() -> {
 
-		Expression expression = PARSER.parseExpression(value, ParserContext.TEMPLATE_EXPRESSION);
+					if (entity instanceof MongoPersistentEntity<?> mongoPersistentEntity
-		if (expression instanceof LiteralExpression) {
+							&& mongoPersistentEntity.hasCollation()) {
-			return value;
+						return mongoPersistentEntity.getCollation();
-		}
+					}
-
+					return null;
-		return expression.getValue(evaluationContext, Object.class);
+				});
 	}
 
 	private static boolean isMapWithoutWildcardIndex(MongoPersistentProperty property) {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/WildcardIndexed.java

@@ -21,6 +21,9 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
+import org.springframework.data.mongodb.core.annotation.Collation;
+
 /**
  * Annotation for an entity or property that should be used as key for a
  * <a href="https://docs.mongodb.com/manual/core/index-wildcard/">Wildcard Index</a>. <br />
@@ -79,6 +82,7 @@ import java.lang.annotation.Target;
  * @author Christoph Strobl
  * @since 3.3
  */
+@Collation
 @Documented
 @Target({ ElementType.TYPE, ElementType.FIELD })
 @Retention(RetentionPolicy.RUNTIME)
@@ -126,5 +130,6 @@ public @interface WildcardIndexed {
 	 *
 	 * @return an empty {@link String} by default.
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/Document.java

@@ -23,6 +23,7 @@ import java.lang.annotation.Target;
 
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.data.annotation.Persistent;
+import org.springframework.data.mongodb.core.annotation.Collation;
 
 /**
  * Identifies a domain object to be persisted to MongoDB.
@@ -32,6 +33,7 @@ import org.springframework.data.annotation.Persistent;
  * @author Christoph Strobl
  */
 @Persistent
+@Collation
 @Inherited
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.TYPE })
@@ -71,6 +73,7 @@ public @interface Document {
 	 * @return an empty {@link String} by default.
 	 * @since 2.2
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/Aggregation.java

@@ -23,6 +23,7 @@ import java.lang.annotation.Target;
 
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.data.annotation.QueryAnnotation;
+import org.springframework.data.mongodb.core.annotation.Collation;
 
 /**
  * The {@link Aggregation} annotation can be used to annotate a {@link org.springframework.data.repository.Repository}
@@ -38,6 +39,7 @@ import org.springframework.data.annotation.QueryAnnotation;
  * @author Christoph Strobl
  * @since 2.2
  */
+@Collation
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.METHOD, ElementType.ANNOTATION_TYPE })
 @Documented
@@ -123,5 +125,6 @@ public @interface Aggregation {
 	 *
 	 * @return an empty {@link String} by default.
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/Query.java

@@ -21,7 +21,9 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
 import org.springframework.data.annotation.QueryAnnotation;
+import org.springframework.data.mongodb.core.annotation.Collation;
 
 /**
  * Annotation to declare finder queries directly on repository methods. Both attributes allow using a placeholder
@@ -32,6 +34,7 @@ import org.springframework.data.annotation.QueryAnnotation;
  * @author Christoph Strobl
  * @author Mark Paluch
  */
+@Collation
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.METHOD, ElementType.ANNOTATION_TYPE })
 @Documented
@@ -124,5 +127,6 @@ public @interface Query {
 	 * @return an empty {@link String} by default.
 	 * @since 2.2
 	 */
+	@AliasFor(annotation = Collation.class, attribute = "value")
 	String collation() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryMethod.java

@@ -28,6 +28,7 @@ import org.springframework.data.geo.GeoPage;
 import org.springframework.data.geo.GeoResult;
 import org.springframework.data.geo.GeoResults;
 import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.core.annotation.Collation;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
@@ -321,14 +322,7 @@ public class MongoQueryMethod extends QueryMethod {
 	 * @since 2.2
 	 */
 	public boolean hasAnnotatedCollation() {
-
+		return doFindAnnotation(Collation.class).map(Collation::value).filter(StringUtils::hasText).isPresent();
-		Optional<String> optionalCollation = lookupQueryAnnotation().map(Query::collation);
-
-		if (!optionalCollation.isPresent()) {
-			optionalCollation = lookupAggregationAnnotation().map(Aggregation::collation);
-		}
-
-		return optionalCollation.filter(StringUtils::hasText).isPresent();
 	}
 
 	/**
@@ -341,10 +335,9 @@ public class MongoQueryMethod extends QueryMethod {
 	 */
 	public String getAnnotatedCollation() {
 
-		return lookupQueryAnnotation().map(Query::collation)
+		return doFindAnnotation(Collation.class).map(Collation::value) //
-				.orElseGet(() -> lookupAggregationAnnotation().map(Aggregation::collation) //
 						.orElseThrow(() -> new IllegalStateException(
-								"Expected to find @Query annotation but did not; Make sure to check hasAnnotatedCollation() before.")));
+								"Expected to find @Collation annotation but did not; Make sure to check hasAnnotatedCollation() before."));
 	}
 
 	/**
@@ -447,7 +440,7 @@ public class MongoQueryMethod extends QueryMethod {
 	private boolean isNumericOrVoidReturnValue() {
 
 		Class<?> resultType = getReturnedObjectType();
-		if(ReactiveWrappers.usesReactiveType(resultType)) {
+		if (ReactiveWrappers.usesReactiveType(resultType)) {
 			resultType = getReturnType().getComponentType().getType();
 		}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/util/spel/ExpressionUtils.java

@@ -15,6 +15,9 @@
  */
 package org.springframework.data.mongodb.util.spel;
 
+import java.util.function.Supplier;
+
+import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ParserContext;
 import org.springframework.expression.common.LiteralExpression;
@@ -49,4 +52,15 @@ public final class ExpressionUtils {
 		Expression expression = PARSER.parseExpression(potentialExpression, ParserContext.TEMPLATE_EXPRESSION);
 		return expression instanceof LiteralExpression ? null : expression;
 	}
+
+	@Nullable
+	public static Object evaluate(String value, Supplier<EvaluationContext> evaluationContext) {
+
+		Expression expression = detectExpression(value);
+		if (expression == null) {
+			return value;
+		}
+
+		return expression.getValue(evaluationContext.get(), Object.class);
+	}
 }

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexResolverUnitTests.java

@@ -713,6 +713,32 @@ public class MongoPersistentEntityIndexResolverUnitTests {
 			assertThat(indexDefinition.getIndexKeys()).isEqualTo(new org.bson.Document().append("foo", 1));
 		}
 
+		@Test // GH-3002
+		public void compoundIndexWithCollationFromDocumentAnnotation() {
+
+			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(
+					WithCompoundCollationFromDocument.class);
+
+			IndexDefinition indexDefinition = indexDefinitions.get(0).getIndexDefinition();
+			assertThat(indexDefinition.getIndexOptions())
+					.isEqualTo(new org.bson.Document().append("name", "compound_index_with_collation").append("collation",
+							new org.bson.Document().append("locale", "en_US").append("strength", 2)));
+			assertThat(indexDefinition.getIndexKeys()).isEqualTo(new org.bson.Document().append("foo", 1));
+		}
+
+		@Test // GH-3002
+		public void compoundIndexWithEvaluatedCollationFromAnnotation() {
+
+			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(
+					WithEvaluatedCollationFromCompoundIndex.class);
+
+			IndexDefinition indexDefinition = indexDefinitions.get(0).getIndexDefinition();
+			assertThat(indexDefinition.getIndexOptions())
+					.isEqualTo(new org.bson.Document().append("name", "compound_index_with_collation").append("collation",
+							new org.bson.Document().append("locale", "de_AT")));
+			assertThat(indexDefinition.getIndexKeys()).isEqualTo(new org.bson.Document().append("foo", 1));
+		}
+
 		@Document("CompoundIndexOnLevelOne")
 		class CompoundIndexOnLevelOne {
 
@@ -793,6 +819,14 @@ public class MongoPersistentEntityIndexResolverUnitTests {
 		@CompoundIndex(name = "compound_index_with_collation", def = "{'foo': 1}",
 				collation = "{'locale': 'en_US', 'strength': 2}")
 		class CompoundIndexWithCollation {}
+
+		@Document(collation = "{'locale': 'en_US', 'strength': 2}")
+		@CompoundIndex(name = "compound_index_with_collation", def = "{'foo': 1}")
+		class WithCompoundCollationFromDocument {}
+
+		@Document(collation = "{'locale': 'en_US', 'strength': 2}")
+		@CompoundIndex(name = "compound_index_with_collation", def = "{'foo': 1}", collation = "#{{ 'locale' : 'de' + '_' + 'AT' }}")
+		class WithEvaluatedCollationFromCompoundIndex {}
 	}
 
 	public static class TextIndexedResolutionTests {
@@ -1423,7 +1457,7 @@ public class MongoPersistentEntityIndexResolverUnitTests {
 		public void indexedWithCollation() {
 
 			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(
-					IndexedWithCollation.class);
+					WithCollationFromIndexedAnnotation.class);
 
 			IndexDefinition indexDefinition = indexDefinitions.get(0).getIndexDefinition();
 			assertThat(indexDefinition.getIndexOptions()).isEqualTo(new org.bson.Document().append("name", "value")
@@ -1431,6 +1465,29 @@ public class MongoPersistentEntityIndexResolverUnitTests {
 					.append("collation", new org.bson.Document().append("locale", "en_US").append("strength", 2)));
 		}
 
+		@Test // GH-3002
+		public void indexedWithCollationFromDocumentAnnotation() {
+
+			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(
+					WithCollationFromDocumentAnnotation.class);
+
+			IndexDefinition indexDefinition = indexDefinitions.get(0).getIndexDefinition();
+			assertThat(indexDefinition.getIndexOptions()).isEqualTo(new org.bson.Document().append("name", "value")
+					.append("unique", true)
+					.append("collation", new org.bson.Document().append("locale", "en_US").append("strength", 2)));
+		}
+
+		@Test // GH-3002
+		public void indexedWithEvaluatedCollation() {
+
+			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(
+					WithEvaluatedCollationFromIndexedAnnotation.class);
+
+			IndexDefinition indexDefinition = indexDefinitions.get(0).getIndexDefinition();
+			assertThat(indexDefinition.getIndexOptions()).isEqualTo(new org.bson.Document().append("name", "value")
+					.append("collation", new org.bson.Document().append("locale", "de_AT")));
+		}
+
 		@Document
 		class MixedIndexRoot {
 
@@ -1749,11 +1806,26 @@ public class MongoPersistentEntityIndexResolverUnitTests {
 		}
 
 		@Document
-		class IndexedWithCollation {
+		class WithCollationFromIndexedAnnotation {
+
 			@Indexed(collation = "{'locale': 'en_US', 'strength': 2}", unique = true) //
 			private String value;
 		}
 
+		@Document(collation = "{'locale': 'en_US', 'strength': 2}")
+		class WithCollationFromDocumentAnnotation {
+
+			@Indexed(unique = true) //
+			private String value;
+		}
+
+		@Document(collation = "en_US")
+		class WithEvaluatedCollationFromIndexedAnnotation {
+
+			@Indexed(collation = "#{{'locale' :  'de' + '_' + 'AT'}}") //
+			private String value;
+		}
+
 		@HashIndexed
 		@Indexed
 		@Retention(RetentionPolicy.RUNTIME)

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/MongoQueryMethodUnitTests.java

@@ -31,6 +31,7 @@ import org.springframework.data.geo.GeoResults;
 import org.springframework.data.geo.Point;
 import org.springframework.data.mongodb.core.User;
 import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
+import org.springframework.data.mongodb.core.annotation.Collation;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.query.Update;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
@@ -39,6 +40,7 @@ import org.springframework.data.mongodb.repository.Aggregation;
 import org.springframework.data.mongodb.repository.Contact;
 import org.springframework.data.mongodb.repository.Meta;
 import org.springframework.data.mongodb.repository.Person;
+import org.springframework.data.mongodb.repository.Query;
 import org.springframework.data.projection.ProjectionFactory;
 import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
 import org.springframework.data.repository.Repository;
@@ -278,6 +280,33 @@ public class MongoQueryMethodUnitTests {
 				.withMessageContaining("findAndIncrementVisitsByFirstname");
 	}
 
+	@Test // GH-3002
+	void readsCollationFromAtCollationAnnotation() throws Exception {
+
+		MongoQueryMethod method = queryMethod(PersonRepository.class, "findWithCollationFromAtCollationByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("en_US");
+	}
+
+	@Test // GH-3002
+	void readsCollationFromAtQueryAnnotation() throws Exception {
+
+		MongoQueryMethod method = queryMethod(PersonRepository.class, "findWithCollationFromAtQueryByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("en_US");
+	}
+
+	@Test // GH-3002
+	void annotatedCollationClashSelectsAtCollationAnnotationValue() throws Exception {
+
+		MongoQueryMethod method = queryMethod(PersonRepository.class, "findWithMultipleCollationsFromAtQueryAndAtCollationByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("de_AT");
+	}
+
 	private MongoQueryMethod queryMethod(Class<?> repository, String name, Class<?>... parameters) throws Exception {
 
 		Method method = repository.getMethod(name, parameters);
@@ -338,6 +367,16 @@ public class MongoQueryMethodUnitTests {
 		void findAndUpdateBy(String firstname, UpdateDefinition update);
 
 		void findAndUpdateBy(String firstname, AggregationUpdate update);
+
+		@Collation("en_US")
+		List<User> findWithCollationFromAtCollationByFirstname(String firstname);
+
+		@Query(collation = "en_US")
+		List<User> findWithCollationFromAtQueryByFirstname(String firstname);
+
+		@Collation("de_AT")
+		@Query(collation = "en_US")
+		List<User> findWithMultipleCollationsFromAtQueryAndAtCollationByFirstname(String firstname);
 	}
 
 	interface SampleRepository extends Repository<Contact, Long> {

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/ReactiveMongoQueryMethodUnitTests.java

@@ -17,6 +17,10 @@ package org.springframework.data.mongodb.repository.query;
 
 import static org.assertj.core.api.Assertions.*;
 
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.data.mongodb.core.annotation.Collation;
+import org.springframework.data.mongodb.repository.Query;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -24,8 +28,6 @@ import java.lang.reflect.Method;
 import java.util.List;
 
 import org.assertj.core.api.Assertions;
-import org.junit.Before;
-import org.junit.Test;
 
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.domain.Page;
@@ -56,7 +58,7 @@ public class ReactiveMongoQueryMethodUnitTests {
 
 	MongoMappingContext context;
 
-	@Before
+	@BeforeEach
 	public void setUp() {
 		context = new MongoMappingContext();
 	}
@@ -102,13 +104,13 @@ public class ReactiveMongoQueryMethodUnitTests {
 				.isTrue();
 	}
 
-	@Test(expected = IllegalArgumentException.class) // DATAMONGO-1444
+	@Test // DATAMONGO-1444
 	public void rejectsNullMappingContext() throws Exception {
 
 		Method method = PersonRepository.class.getMethod("findByFirstname", String.class, Point.class);
 
-		new MongoQueryMethod(method, new DefaultRepositoryMetadata(PersonRepository.class),
+		assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> new MongoQueryMethod(method, new DefaultRepositoryMetadata(PersonRepository.class),
-				new SpelAwareProxyProjectionFactory(), null);
+				new SpelAwareProxyProjectionFactory(), null));
 	}
 
 	@Test // DATAMONGO-1444
@@ -197,6 +199,33 @@ public class ReactiveMongoQueryMethodUnitTests {
 				.withMessageContaining("findAndIncrementVisitsByFirstname");
 	}
 
+	@Test // GH-3002
+	void readsCollationFromAtCollationAnnotation() throws Exception {
+
+		ReactiveMongoQueryMethod method = queryMethod(MongoQueryMethodUnitTests.PersonRepository.class, "findWithCollationFromAtCollationByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("en_US");
+	}
+
+	@Test // GH-3002
+	void readsCollationFromAtQueryAnnotation() throws Exception {
+
+		ReactiveMongoQueryMethod method = queryMethod(MongoQueryMethodUnitTests.PersonRepository.class, "findWithCollationFromAtQueryByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("en_US");
+	}
+
+	@Test // GH-3002
+	void annotatedCollationClashSelectsAtCollationAnnotationValue() throws Exception {
+
+		ReactiveMongoQueryMethod method = queryMethod(MongoQueryMethodUnitTests.PersonRepository.class, "findWithMultipleCollationsFromAtQueryAndAtCollationByFirstname", String.class);
+
+		assertThat(method.hasAnnotatedCollation()).isTrue();
+		assertThat(method.getAnnotatedCollation()).isEqualTo("de_AT");
+	}
+
 	private ReactiveMongoQueryMethod queryMethod(Class<?> repository, String name, Class<?>... parameters)
 			throws Exception {
 
@@ -238,6 +267,16 @@ public class ReactiveMongoQueryMethodUnitTests {
 		@Aggregation(pipeline = "{'$group': { _id: '$templateId', maxVersion : { $max : '$version'} } }",
 				collation = "de_AT")
 		Flux<User> findByAggregationWithCollation();
+
+		@Collation("en_US")
+		List<User> findWithCollationFromAtCollationByFirstname(String firstname);
+
+		@Query(collation = "en_US")
+		List<User> findWithCollationFromAtQueryByFirstname(String firstname);
+
+		@Collation("de_AT")
+		@Query(collation = "en_US")
+		List<User> findWithMultipleCollationsFromAtQueryAndAtCollationByFirstname(String firstname);
 	}
 
 	interface SampleRepository extends Repository<Contact, Long> {

src/main/asciidoc/reference/mongodb.adoc

@@ -2011,7 +2011,35 @@ and `Document` (eg. new Document("locale", "en_US"))
 NOTE: In case you enabled the automatic index creation for repository finder methods a potential static collation definition,
 as shown in (1) and (2), will be included when creating the index.
 
-TIP: The most specifc `Collation` outroules potentially defined others. Which means Method argument over query method annotation over doamin type annotation.
+TIP: The most specifc `Collation` outrules potentially defined others. Which means Method argument over query method annotation over domain type annotation.
+====
+
+To streamline usage of collation attributes throughout the codebase it is also possible to use the `@Collation` annotation, which serves as a meta annotation for the ones mentioned above.
+The same rules and locations apply, plus, direct usage of `@Collation` supersedes any collation values defined on `@Query` and other annotations.
+Which means, if a collation is declared via `@Query` and additionally via `@Collation`, then the one from `@Collation` is picked.
+
+.Using `@Collation`
+====
+[source,java]
+----
+@Collation("en_US") <1>
+class Game {
+  // ...
+}
+
+interface GameRepository extends Repository<Game, String> {
+
+  @Collation("en_GB")  <2>
+  List<Game> findByTitle(String title);
+
+  @Collation("de_AT")  <3>
+  @Query(collation="en_GB")
+  List<Game> findByDescriptionContaining(String keyword);
+}
+----
+<1> Instead of `@Document(collation=...)`.
+<2> Instead of `@Query(collation=...)`.
+<3> Favors `@Collation` over meta usage.
 ====
 
 include::./mongo-json-schema.adoc[leveloffset=+1]