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mp911demp911de
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Refine DTO projection rewriting.
We now consider dropping aliases (count(foo) as foo), support subselects and capture individual select items to avoid contextual information loss. Also, added a series of tests to cover edgecases. See #3895
1 parent 61a1a8c commit 5a22fbf

17 files changed

+592
-339
lines changed

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/AbstractJpaQuery.java‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -24,6 +24,7 @@
2424
import jakarta.persistence.TypedQuery;
2525

2626
import java.lang.reflect.Constructor;
27+
import java.util.AbstractMap;
2728
import java.util.ArrayList;
2829
import java.util.Arrays;
2930
import java.util.Collection;
@@ -474,7 +475,7 @@ private static boolean areAssignmentCompatible(Class<?> to, Class<?> from) {
474475
*
475476
* @author Jens Schauder
476477
*/
477-
private static class TupleBackedMap implements Map<String, Object> {
478+
private static class TupleBackedMap extends AbstractMap<String, Object> implements Map<String, Object> {
478479

479480
private static final String UNMODIFIABLE_MESSAGE = "A TupleBackedMap cannot be modified";
480481

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/AbstractStringBasedJpaQuery.java‎

Lines changed: 1 addition & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -27,8 +27,6 @@
2727
import org.springframework.data.domain.Sort;
2828
import org.springframework.data.expression.ValueEvaluationContextProvider;
2929
import org.springframework.data.jpa.repository.QueryRewriter;
30-
import org.springframework.data.mapping.PropertyPath;
31-
import org.springframework.data.mapping.PropertyReferenceException;
3230
import org.springframework.data.repository.query.ResultProcessor;
3331
import org.springframework.data.repository.query.ReturnedType;
3432
import org.springframework.data.repository.query.ValueExpressionDelegate;
@@ -166,52 +164,7 @@ ReturnedType getReturnedType(ResultProcessor processor) {
166164
return new NonProjectingReturnedType(returnedType);
167165
}
168166

169-
if (query.isDefaultProjection()) {
170-
return returnedType;
171-
}
172-
173-
String alias = query.getAlias();
174-
String projection = query.getProjection();
175-
176-
// we can handle single-column and no function projections here only
177-
if (StringUtils.hasText(projection) && (projection.indexOf(',') != -1 || projection.indexOf('(') != -1)) {
178-
return returnedType;
179-
}
180-
181-
if (StringUtils.hasText(alias) && StringUtils.hasText(projection)) {
182-
alias = alias.trim();
183-
projection = projection.trim();
184-
if (projection.startsWith(alias + ".")) {
185-
projection = projection.substring(alias.length() + 1);
186-
}
187-
}
188-
189-
if (StringUtils.hasText(projection)) {
190-
191-
int space = projection.indexOf(' ');
192-
193-
if (space != -1) {
194-
projection = projection.substring(0, space);
195-
}
196-
197-
Class<?> propertyType;
198-
199-
try {
200-
PropertyPath from = PropertyPath.from(projection, getQueryMethod().getEntityInformation().getJavaType());
201-
propertyType = from.getLeafType();
202-
} catch (PropertyReferenceException ignored) {
203-
propertyType = null;
204-
}
205-
206-
if (propertyType == null
207-
|| (returnedJavaType.isAssignableFrom(propertyType) || propertyType.isAssignableFrom(returnedJavaType))) {
208-
knownProjections.put(returnedJavaType, false);
209-
return new NonProjectingReturnedType(returnedType);
210-
} else {
211-
knownProjections.put(returnedJavaType, true);
212-
}
213-
}
214-
167+
knownProjections.put(returnedJavaType, true);
215168
return returnedType;
216169
}
217170

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/DtoProjectionTransformerDelegate.java‎

Lines changed: 80 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -17,6 +17,11 @@
1717

1818
import static org.springframework.data.jpa.repository.query.QueryTokens.*;
1919

20+
import java.util.ArrayList;
21+
import java.util.Iterator;
22+
import java.util.List;
23+
import java.util.function.Function;
24+
2025
import org.springframework.data.repository.query.ReturnedType;
2126

2227
/**
@@ -25,7 +30,8 @@
2530
* Query rewriting from a plain property/object selection towards constructor expression only works if either:
2631
* <ul>
2732
* <li>The query selects its primary alias ({@code SELECT p FROM Person p})</li>
28-
* <li>The query specifies a property list ({@code SELECT p.foo, p.bar FROM Person p})</li>
33+
* <li>The query specifies a property list ({@code SELECT p.foo, p.bar FROM Person p},
34+
* {@code SELECT COUNT(p.foo), p.bar AS bar FROM Person p})</li>
2935
* </ul>
3036
*
3137
* @author Mark Paluch
@@ -34,42 +40,94 @@
3440
class DtoProjectionTransformerDelegate {
3541

3642
private final ReturnedType returnedType;
43+
private final boolean applyRewriting;
44+
private final List<QueryTokenStream> selectItems = new ArrayList<>();
3745

3846
public DtoProjectionTransformerDelegate(ReturnedType returnedType) {
3947
this.returnedType = returnedType;
48+
this.applyRewriting = returnedType.isProjecting() && !returnedType.getReturnedType().isInterface()
49+
&& returnedType.needsCustomConstruction();
50+
}
51+
52+
public boolean applyRewriting() {
53+
return applyRewriting;
54+
}
55+
56+
public boolean canRewrite() {
57+
return applyRewriting() && !selectItems.isEmpty();
58+
}
59+
60+
public void appendSelectItem(QueryTokenStream selectItem) {
61+
62+
if (applyRewriting()) {
63+
selectItems.add(new DetachedStream(selectItem));
64+
}
4065
}
4166

42-
public QueryTokenStream transformSelectionList(QueryTokenStream selectionList) {
67+
public QueryTokenStream getRewrittenSelectionList() {
68+
69+
if (canRewrite()) {
70+
71+
QueryRenderer.QueryRendererBuilder builder = QueryRenderer.builder();
72+
builder.append(QueryTokens.TOKEN_NEW);
73+
builder.append(QueryTokens.token(returnedType.getReturnedType().getName()));
74+
builder.append(QueryTokens.TOKEN_OPEN_PAREN);
75+
76+
if (selectItems.size() == 1 && selectItems.get(0).size() == 1) {
4377

44-
if (!returnedType.isProjecting() || returnedType.getReturnedType().isInterface()
45-
|| !returnedType.needsCustomConstruction() || selectionList.stream().anyMatch(it -> it.equals(TOKEN_NEW))) {
46-
return selectionList;
78+
builder.appendInline(QueryTokenStream.concat(returnedType.getInputProperties(), property -> {
79+
80+
QueryRenderer.QueryRendererBuilder prop = QueryRenderer.builder();
81+
prop.appendInline(selectItems.get(0));
82+
prop.append(QueryTokens.TOKEN_DOT);
83+
prop.append(QueryTokens.token(property));
84+
85+
return prop.build();
86+
}, QueryTokens.TOKEN_COMMA));
87+
} else {
88+
builder.append(QueryTokenStream.concat(selectItems, Function.identity(), TOKEN_COMMA));
89+
}
90+
91+
builder.append(TOKEN_CLOSE_PAREN);
92+
93+
return builder.build();
4794
}
4895

49-
QueryRenderer.QueryRendererBuilder builder = QueryRenderer.builder();
50-
builder.append(QueryTokens.TOKEN_NEW);
51-
builder.append(QueryTokens.token(returnedType.getReturnedType().getName()));
52-
builder.append(QueryTokens.TOKEN_OPEN_PAREN);
96+
return QueryTokenStream.empty();
97+
}
98+
99+
private static class DetachedStream extends QueryRenderer {
53100

54-
// assume the selection points to the document
55-
if (selectionList.size() == 1) {
101+
private final QueryTokenStream delegate;
56102

57-
builder.appendInline(QueryTokenStream.concat(returnedType.getInputProperties(), property -> {
103+
private DetachedStream(QueryTokenStream delegate) {
104+
this.delegate = delegate;
105+
}
58106

59-
QueryRenderer.QueryRendererBuilder prop = QueryRenderer.builder();
60-
prop.append(QueryTokens.token(selectionList.getFirst().value()));
61-
prop.append(QueryTokens.TOKEN_DOT);
62-
prop.append(QueryTokens.token(property));
107+
@Override
108+
public boolean isExpression() {
109+
return delegate.isExpression();
110+
}
63111

64-
return prop.build();
65-
}, QueryTokens.TOKEN_COMMA));
112+
@Override
113+
public int size() {
114+
return delegate.size();
115+
}
66116

67-
} else {
68-
builder.appendInline(selectionList);
117+
@Override
118+
public boolean isEmpty() {
119+
return delegate.isEmpty();
69120
}
70121

71-
builder.append(QueryTokens.TOKEN_CLOSE_PAREN);
122+
@Override
123+
public Iterator<QueryToken> iterator() {
124+
return delegate.iterator();
125+
}
72126

73-
return builder.build();
127+
@Override
128+
public String render() {
129+
return delegate instanceof QueryRenderer ? ((QueryRenderer) delegate).render() : delegate.toString();
130+
}
74131
}
132+
75133
}

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/EqlQueryRenderer.java‎

Lines changed: 12 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -292,8 +292,7 @@ public QueryTokenStream visitJoin_condition(EqlParser.Join_conditionContext ctx)
292292
}
293293

294294
@Override
295-
public QueryTokenStream visitJoin_association_path_expression(
296-
EqlParser.Join_association_path_expressionContext ctx) {
295+
public QueryTokenStream visitJoin_association_path_expression(EqlParser.Join_association_path_expressionContext ctx) {
297296

298297
QueryRendererBuilder builder = QueryRenderer.builder();
299298

@@ -451,8 +450,7 @@ public QueryTokenStream visitSingle_valued_path_expression(EqlParser.Single_valu
451450
}
452451

453452
@Override
454-
public QueryTokenStream visitGeneral_identification_variable(
455-
EqlParser.General_identification_variableContext ctx) {
453+
public QueryTokenStream visitGeneral_identification_variable(EqlParser.General_identification_variableContext ctx) {
456454

457455
QueryRendererBuilder builder = QueryRenderer.builder();
458456

@@ -641,6 +639,15 @@ public QueryTokenStream visitDelete_clause(EqlParser.Delete_clauseContext ctx) {
641639
@Override
642640
public QueryTokenStream visitSelect_clause(EqlParser.Select_clauseContext ctx) {
643641

642+
QueryRendererBuilder builder = prepareSelectClause(ctx);
643+
644+
builder.appendExpression(QueryTokenStream.concat(ctx.select_item(), this::visit, TOKEN_COMMA));
645+
646+
return builder;
647+
}
648+
649+
QueryRendererBuilder prepareSelectClause(EqlParser.Select_clauseContext ctx) {
650+
644651
QueryRendererBuilder builder = QueryRenderer.builder();
645652

646653
builder.append(QueryTokens.expression(ctx.SELECT()));
@@ -649,8 +656,6 @@ public QueryTokenStream visitSelect_clause(EqlParser.Select_clauseContext ctx) {
649656
builder.append(QueryTokens.expression(ctx.DISTINCT()));
650657
}
651658

652-
builder.appendExpression(QueryTokenStream.concat(ctx.select_item(), this::visit, TOKEN_COMMA));
653-
654659
return builder;
655660
}
656661

@@ -2448,8 +2453,7 @@ public QueryTokenStream visitFunction_name(EqlParser.Function_nameContext ctx) {
24482453
}
24492454

24502455
@Override
2451-
public QueryTokenStream visitCharacter_valued_input_parameter(
2452-
EqlParser.Character_valued_input_parameterContext ctx) {
2456+
public QueryTokenStream visitCharacter_valued_input_parameter(EqlParser.Character_valued_input_parameterContext ctx) {
24532457

24542458
if (ctx.CHARACTER() != null) {
24552459
return QueryRendererBuilder.from(QueryTokens.expression(ctx.CHARACTER()));

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/EqlSortedQueryTransformer.java‎

Lines changed: 42 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -91,17 +91,53 @@ public QueryTokenStream visitSelect_clause(EqlParser.Select_clauseContext ctx) {
9191
return super.visitSelect_clause(ctx);
9292
}
9393

94-
QueryRendererBuilder builder = QueryRenderer.builder();
94+
QueryRendererBuilder builder = prepareSelectClause(ctx);
9595

96-
builder.append(QueryTokens.expression(ctx.SELECT()));
96+
QueryTokenStream selectItems = QueryTokenStream.concat(ctx.select_item(), this::visit, TOKEN_COMMA);
9797

98-
if (ctx.DISTINCT() != null) {
99-
builder.append(QueryTokens.expression(ctx.DISTINCT()));
98+
if (dtoDelegate != null && dtoDelegate.canRewrite()) {
99+
builder.append(dtoDelegate.getRewrittenSelectionList());
100+
} else {
101+
builder.append(selectItems);
100102
}
101103

102-
QueryTokenStream tokenStream = QueryTokenStream.concat(ctx.select_item(), this::visit, TOKEN_COMMA);
104+
return builder;
105+
}
106+
107+
@Override
108+
public QueryTokenStream visitSelect_item(EqlParser.Select_itemContext ctx) {
109+
110+
QueryTokenStream tokens = super.visitSelect_item(ctx);
111+
112+
if (ctx.result_variable() != null && !tokens.isEmpty()) {
113+
transformerSupport.registerAlias(ctx.result_variable().getText());
114+
}
115+
116+
return tokens;
117+
}
118+
119+
@Override
120+
public QueryTokenStream visitSelect_expression(EqlParser.Select_expressionContext ctx) {
121+
122+
QueryTokenStream selectItem = super.visitSelect_expression(ctx);
123+
124+
if (dtoDelegate != null && dtoDelegate.applyRewriting() && ctx.constructor_expression() == null) {
125+
dtoDelegate.appendSelectItem(selectItem);
126+
}
127+
128+
return selectItem;
129+
}
130+
131+
@Override
132+
public QueryTokenStream visitJoin(EqlParser.JoinContext ctx) {
133+
134+
QueryTokenStream tokens = super.visitJoin(ctx);
135+
136+
if (ctx.identification_variable() != null) {
137+
transformerSupport.registerAlias(ctx.identification_variable().getText());
138+
}
103139

104-
return builder.append(dtoDelegate.transformSelectionList(tokenStream));
140+
return tokens;
105141
}
106142

107143
private void doVisitOrderBy(QueryRendererBuilder builder, EqlParser.Select_statementContext ctx, Sort sort) {
@@ -131,28 +167,4 @@ private void doVisitOrderBy(QueryRendererBuilder builder, EqlParser.Select_state
131167
}
132168
}
133169

134-
@Override
135-
public QueryTokenStream visitSelect_item(EqlParser.Select_itemContext ctx) {
136-
137-
QueryTokenStream tokens = super.visitSelect_item(ctx);
138-
139-
if (ctx.result_variable() != null && !tokens.isEmpty()) {
140-
transformerSupport.registerAlias(tokens.getLast());
141-
}
142-
143-
return tokens;
144-
}
145-
146-
@Override
147-
public QueryTokenStream visitJoin(EqlParser.JoinContext ctx) {
148-
149-
QueryTokenStream tokens = super.visitJoin(ctx);
150-
151-
if (!tokens.isEmpty()) {
152-
transformerSupport.registerAlias(tokens.getLast());
153-
}
154-
155-
return tokens;
156-
}
157-
158170
}

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/HqlCountQueryTransformer.java‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -103,13 +103,12 @@ public QueryRendererBuilder visitFromQuery(HqlParser.FromQueryContext ctx) {
103103

104104
if (ctx.fromClause() != null) {
105105
builder.appendExpression(visit(ctx.fromClause()));
106-
if(primaryFromAlias == null) {
106+
if (primaryFromAlias == null) {
107107
builder.append(TOKEN_AS);
108108
builder.append(TOKEN_DOUBLE_UNDERSCORE);
109109
}
110110
}
111111

112-
113112
if (ctx.whereClause() != null) {
114113
builder.appendExpression(visit(ctx.whereClause()));
115114
}

‎spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/HqlQueryRenderer.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -830,7 +830,7 @@ public QueryTokenStream visitSelection(HqlParser.SelectionContext ctx) {
830830
builder.appendExpression(visit(ctx.variable()));
831831
}
832832

833-
return builder;
833+
return builder.toInline();
834834
}
835835

836836
@Override

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