Polishing.

Omit StreamUtils usage if input is a collection. Remove superfluous Flux.from(…). Simplify test and migrate test to JUnit 5.

See spring-projects#3609.
Original pull request: spring-projects#3611.

Author: mp911de

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

@@ -18,6 +18,7 @@
 import static org.springframework.data.mongodb.core.query.Criteria.*;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
@@ -291,10 +292,10 @@ public <S extends T> List<S> insert(Iterable<S> entities) {
 
 		Assert.notNull(entities, "The given Iterable of entities not be null!");
 
-		List<S> list = Streamable.of(entities).stream().collect(StreamUtils.toUnmodifiableList());
+		Collection<S> list = toCollection(entities);
 
 		if (list.isEmpty()) {
-			return list;
+			return Collections.emptyList();
 		}
 
 		return new ArrayList<>(mongoOperations.insertAll(list));
@@ -408,8 +409,14 @@ private Criteria getIdCriteria(Object id) {
 	}
 
 	private Query getIdQuery(Iterable<? extends ID> ids) {
+
 		return new Query(new Criteria(entityInformation.getIdAttribute())
-				.in(Streamable.of(ids).stream().collect(StreamUtils.toUnmodifiableList())));
+				.in(toCollection(ids)));
+	}
+
+	private static <E> Collection<E> toCollection(Iterable<E> ids) {
+		return ids instanceof Collection ? (Collection<E>) ids
+				: StreamUtils.createStreamFromIterator(ids.iterator()).collect(Collectors.toList());
 	}
 
 	private List<T> findAll(@Nullable Query query) {

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

@@ -22,7 +22,6 @@
 
 import java.io.Serializable;
 import java.util.Collection;
-import java.util.List;
 import java.util.stream.Collectors;
 
 import org.reactivestreams.Publisher;
@@ -364,9 +363,9 @@ public <S extends T> Flux<S> insert(Iterable<S> entities) {
 
 		Assert.notNull(entities, "The given Iterable of entities must not be null!");
 
-		List<S> source = Streamable.of(entities).stream().collect(StreamUtils.toUnmodifiableList());
+		Collection<S> source = toCollection(entities);
 
-		return source.isEmpty() ? Flux.empty() : Flux.from(mongoOperations.insertAll(source));
+		return source.isEmpty() ? Flux.empty() : mongoOperations.insertAll(source);
 	}
 
 	/*
@@ -467,7 +466,6 @@ public <S extends T> Mono<Boolean> exists(Example<S> example) {
 		return mongoOperations.exists(query, example.getProbeType(), entityInformation.getCollectionName());
 	}
 
-
 	private Query getIdQuery(Object id) {
 		return new Query(getIdCriteria(id));
 	}
@@ -477,14 +475,15 @@ private Criteria getIdCriteria(Object id) {
 	}
 
 	private Query getIdQuery(Iterable<? extends ID> ids) {
-		Collection<?> idCollection = StreamUtils.createStreamFromIterator(ids.iterator()).collect(Collectors.toList());
-		Criteria idsInCriteria = where(entityInformation.getIdAttribute()).in(idCollection);
+		return new Query(where(entityInformation.getIdAttribute()).in(toCollection(ids)));
+	}
 
-		return new Query(idsInCriteria);
+	private static <E> Collection<E> toCollection(Iterable<E> ids) {
+		return ids instanceof Collection ? (Collection<E>) ids
+				: StreamUtils.createStreamFromIterator(ids.iterator()).collect(Collectors.toList());
 	}
 
 	private Flux<T> findAll(Query query) {
-
 		return mongoOperations.find(query, entityInformation.getJavaType(), entityInformation.getCollectionName());
 	}
 }