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christophstroblmp911de
christophstrobl
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mp911de
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Polishing.
Wrap no results predicate in dedicated lookup filter and make sure to omit loading attempt also for map properties. See #4612 Original pull request: #4613
1 parent 521fcb1 commit dd9f0bc

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3 files changed

+80
-36
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3 files changed

+80
-36
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‎spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ReferenceLoader.java

+26
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,7 @@
2121
import org.bson.Document;
2222
import org.bson.conversions.Bson;
2323
import org.springframework.data.mongodb.core.convert.ReferenceResolver.ReferenceCollection;
24+
import org.springframework.data.mongodb.core.mapping.FieldName;
2425
import org.springframework.lang.Nullable;
2526

2627
import com.mongodb.client.MongoCollection;
@@ -126,5 +127,30 @@ public Iterable<Document> apply(MongoCollection<Document> collection) {
126127
}
127128
};
128129
}
130+
131+
/**
132+
* @return a {@link DocumentReferenceQuery} that will not match any documents.
133+
* @since 4.3
134+
*/
135+
static DocumentReferenceQuery forNoResult() {
136+
return NoResultsFilter.INSTANCE;
137+
}
138+
}
139+
140+
/**
141+
* A dedicated {@link DocumentReferenceQuery} that will not match any documents.
142+
*
143+
* @since 4.3
144+
*/
145+
enum NoResultsFilter implements DocumentReferenceQuery {
146+
INSTANCE;
147+
148+
private static final Document NO_RESULTS_PREDICATE = new Document(FieldName.ID.name(),
149+
new Document("$exists", false));
150+
151+
@Override
152+
public Bson getQuery() {
153+
return NO_RESULTS_PREDICATE;
154+
}
129155
}
130156
}

‎spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ReferenceLookupDelegate.java

+27-21
Original file line numberDiff line numberDiff line change
@@ -34,10 +34,10 @@
3434
import org.springframework.data.mapping.context.MappingContext;
3535
import org.springframework.data.mapping.model.SpELContext;
3636
import org.springframework.data.mongodb.core.convert.ReferenceLoader.DocumentReferenceQuery;
37+
import org.springframework.data.mongodb.core.convert.ReferenceLoader.NoResultsFilter;
3738
import org.springframework.data.mongodb.core.convert.ReferenceResolver.MongoEntityReader;
3839
import org.springframework.data.mongodb.core.convert.ReferenceResolver.ReferenceCollection;
3940
import org.springframework.data.mongodb.core.mapping.DocumentReference;
40-
import org.springframework.data.mongodb.core.mapping.FieldName;
4141
import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
4242
import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
4343
import org.springframework.data.mongodb.util.BsonUtils;
@@ -49,6 +49,7 @@
4949
import org.springframework.expression.EvaluationContext;
5050
import org.springframework.lang.Nullable;
5151
import org.springframework.util.Assert;
52+
import org.springframework.util.ObjectUtils;
5253
import org.springframework.util.StringUtils;
5354

5455
import com.mongodb.DBRef;
@@ -65,9 +66,6 @@
6566
*/
6667
public final class ReferenceLookupDelegate {
6768

68-
private static final Document NO_RESULTS_PREDICATE = new Document(FieldName.ID.name(),
69-
new Document("$exists", false));
70-
7169
private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
7270
private final SpELContext spELContext;
7371
private final ParameterBindingDocumentCodec codec;
@@ -104,18 +102,15 @@ public ReferenceLookupDelegate(
104102
public Object readReference(MongoPersistentProperty property, Object source, LookupFunction lookupFunction,
105103
MongoEntityReader entityReader) {
106104

107-
Object value = source instanceof DocumentReferenceSource documentReferenceSource ? documentReferenceSource.getTargetSource()
105+
Object value = source instanceof DocumentReferenceSource documentReferenceSource
106+
? documentReferenceSource.getTargetSource()
108107
: source;
109108

110-
// GH-4612 no need to query database if target collection is empty
111-
if (value != null && property.isCollectionLike() && (value instanceof Collection<?> c) && c.isEmpty()) {
112-
return new ArrayList<>();
113-
}
114-
115-
DocumentReferenceQuery filter = computeFilter(property, source, spELContext);
116-
ReferenceCollection referenceCollection = computeReferenceContext(property, value, spELContext);
109+
Iterable<Document> result = retrieveRawDocuments(property, source, lookupFunction, value);
117110

118-
Iterable<Document> result = lookupFunction.apply(filter, referenceCollection);
111+
if (result == null) {
112+
return null;
113+
}
119114

120115
if (property.isCollectionLike()) {
121116
return entityReader.read(result, property.getTypeInformation());
@@ -129,6 +124,19 @@ public Object readReference(MongoPersistentProperty property, Object source, Loo
129124
return resultValue != null ? entityReader.read(resultValue, property.getTypeInformation()) : null;
130125
}
131126

127+
@Nullable
128+
private Iterable<Document> retrieveRawDocuments(MongoPersistentProperty property, Object source,
129+
LookupFunction lookupFunction, Object value) {
130+
131+
DocumentReferenceQuery filter = computeFilter(property, source, spELContext);
132+
if (filter instanceof NoResultsFilter) {
133+
return Collections.emptyList();
134+
}
135+
136+
ReferenceCollection referenceCollection = computeReferenceContext(property, value, spELContext);
137+
return lookupFunction.apply(filter, referenceCollection);
138+
}
139+
132140
private ReferenceCollection computeReferenceContext(MongoPersistentProperty property, Object value,
133141
SpELContext spELContext) {
134142

@@ -278,7 +286,7 @@ DocumentReferenceQuery computeFilter(MongoPersistentProperty property, Object so
278286
Collection<Object> objects = (Collection<Object>) value;
279287

280288
if (objects.isEmpty()) {
281-
return new ListDocumentReferenceQuery(NO_RESULTS_PREDICATE, sort);
289+
return DocumentReferenceQuery.forNoResult();
282290
}
283291

284292
List<Document> ors = new ArrayList<>(objects.size());
@@ -293,11 +301,11 @@ DocumentReferenceQuery computeFilter(MongoPersistentProperty property, Object so
293301

294302
if (property.isMap() && value instanceof Map) {
295303

296-
Set<Entry<Object, Object>> entries = ((Map<Object, Object>) value).entrySet();
297-
if (entries.isEmpty()) {
298-
return new MapDocumentReferenceQuery(NO_RESULTS_PREDICATE, sort, Collections.emptyMap());
304+
if(ObjectUtils.isEmpty(value)) {
305+
return DocumentReferenceQuery.forNoResult();
299306
}
300307

308+
Set<Entry<Object, Object>> entries = ((Map<Object, Object>) value).entrySet();
301309
Map<Object, Document> filterMap = new LinkedHashMap<>(entries.size());
302310

303311
for (Entry<Object, Object> entry : entries) {
@@ -411,8 +419,7 @@ public Bson getSort() {
411419
public Iterable<Document> restoreOrder(Iterable<Document> documents) {
412420

413421
Map<String, Object> targetMap = new LinkedHashMap<>();
414-
List<Document> collected = documents instanceof List<Document> list ? list
415-
: Streamable.of(documents).toList();
422+
List<Document> collected = documents instanceof List<Document> list ? list : Streamable.of(documents).toList();
416423

417424
for (Entry<Object, Document> filterMapping : filterOrderMap.entrySet()) {
418425

@@ -444,8 +451,7 @@ public ListDocumentReferenceQuery(Document query, Document sort) {
444451
@Override
445452
public Iterable<Document> restoreOrder(Iterable<Document> documents) {
446453

447-
List<Document> target = documents instanceof List<Document> list ? list
448-
: Streamable.of(documents).toList();
454+
List<Document> target = documents instanceof List<Document> list ? list : Streamable.of(documents).toList();
449455

450456
if (!sort.isEmpty() || !query.containsKey("$or")) {
451457
return target;

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

+27-15
Original file line numberDiff line numberDiff line change
@@ -15,6 +15,11 @@
1515
*/
1616
package org.springframework.data.mongodb.core.convert;
1717

18+
import static org.assertj.core.api.Assertions.*;
19+
import static org.mockito.Mockito.*;
20+
21+
import java.util.Collections;
22+
1823
import org.junit.jupiter.api.BeforeEach;
1924
import org.junit.jupiter.api.Test;
2025
import org.junit.jupiter.api.extension.ExtendWith;
@@ -28,11 +33,6 @@
2833
import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
2934
import org.springframework.expression.EvaluationContext;
3035

31-
import java.util.Collections;
32-
33-
import static org.assertj.core.api.Assertions.assertThat;
34-
import static org.mockito.Mockito.*;
35-
3636
/**
3737
* Unit tests for {@link ReferenceLookupDelegate}.
3838
*
@@ -53,16 +53,6 @@ void beforeEach() {
5353
lookupDelegate = new ReferenceLookupDelegate(mappingContext, spELContext);
5454
}
5555

56-
@Test // GH-4612
57-
void shouldResolveEmptyListOnEmptyTargetCollection() {
58-
MongoPersistentProperty property = mock(MongoPersistentProperty.class);
59-
ReferenceLookupDelegate.LookupFunction lookupFunction = mock(ReferenceLookupDelegate.LookupFunction.class);
60-
61-
when(property.isCollectionLike()).thenReturn(true);
62-
lookupDelegate.readReference(property, Collections.emptyList(), lookupFunction, entityReader);
63-
verify(lookupFunction, never()).apply(any(), any());
64-
}
65-
6656
@Test // GH-3842
6757
void shouldComputePlainStringTargetCollection() {
6858

@@ -82,4 +72,26 @@ void shouldComputePlainStringTargetCollection() {
8272
return Collections.emptyList();
8373
}, entityReader);
8474
}
75+
76+
@Test // GH-4612
77+
void shouldResolveEmptyListOnEmptyTargetCollection() {
78+
79+
MongoPersistentProperty property = mock(MongoPersistentProperty.class);
80+
ReferenceLookupDelegate.LookupFunction lookupFunction = mock(ReferenceLookupDelegate.LookupFunction.class);
81+
82+
when(property.isCollectionLike()).thenReturn(true);
83+
lookupDelegate.readReference(property, Collections.emptyList(), lookupFunction, entityReader);
84+
verify(lookupFunction, never()).apply(any(), any());
85+
}
86+
87+
@Test // GH-4612
88+
void shouldResolveEmptyMapOnEmptyTargetCollection() {
89+
90+
MongoPersistentProperty property = mock(MongoPersistentProperty.class);
91+
ReferenceLookupDelegate.LookupFunction lookupFunction = mock(ReferenceLookupDelegate.LookupFunction.class);
92+
93+
when(property.isMap()).thenReturn(true);
94+
lookupDelegate.readReference(property, Collections.emptyMap(), lookupFunction, entityReader);
95+
verify(lookupFunction, never()).apply(any(), any());
96+
}
8597
}

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