Fix slice argument in query fields projection.

We now use a Collection instead of an Array to pass on $slice projection values for offset and limit.

Closes: #3811
Original pull request: #3812.

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Field.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.query;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -192,7 +193,7 @@ public Field slice(String field, int size) {
 	 */
 	public Field slice(String field, int offset, int size) {
 
-		slices.put(field, new Integer[] { offset, size });
+		slices.put(field, Arrays.asList(offset, size));
 		return this;
 	}
 

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

@@ -3768,6 +3768,23 @@ void shouldFindSubdocumentWithNullCorrectly() {
 		assertThat(loaded).isNotNull();
 	}
 
+	@Test // GH-3811
+	public void sliceShouldLimitCollectionValues() {
+
+		DocumentWithCollectionOfSimpleType source = new DocumentWithCollectionOfSimpleType();
+		source.id = "id-1";
+		source.values = Arrays.asList("spring", "data", "mongodb");
+
+		template.save(source);
+
+		Criteria criteria = Criteria.where("id").is(source.id);
+		Query query = Query.query(criteria);
+		query.fields().slice("values", 0, 1);
+		DocumentWithCollectionOfSimpleType target = template.findOne(query, DocumentWithCollectionOfSimpleType.class);
+
+		assertThat(target.values).containsExactly("spring");
+	}
+
 	private AtomicReference<ImmutableVersioned> createAfterSaveReference() {
 
 		AtomicReference<ImmutableVersioned> saved = new AtomicReference<>();