DATAJPA-1334 - Fixed named query execution using constructor expressions.

Our named query execution now refrains from using Tuple as return type in case the query uses a constructor expression.

src/main/java/org/springframework/data/jpa/repository/query/NamedQuery.java

@@ -17,6 +17,8 @@ package org.springframework.data.jpa.repository.query;
 
 import static org.springframework.data.jpa.repository.query.QueryParameterSetter.ErrorHandling.*;
 
+import java.util.Optional;
+
 import javax.persistence.EntityManager;
 import javax.persistence.Query;
 import javax.persistence.TypedQuery;
@@ -50,6 +52,7 @@ final class NamedQuery extends AbstractJpaQuery {
 	private final @Nullable String countProjection;
 	private final QueryExtractor extractor;
 	private final boolean namedCountQueryIsPresent;
+	private final DeclaredQuery declaredQuery;
 
 	/**
 	 * Creates a new {@link NamedQuery}.
@@ -72,6 +75,11 @@ final class NamedQuery extends AbstractJpaQuery {
 
 		this.namedCountQueryIsPresent = hasNamedQuery(em, countQueryName);
 
+		Query query = em.createNamedQuery(queryName);
+		String queryString = extractor.extractQueryString(query);
+
+		this.declaredQuery = DeclaredQuery.of(queryString);
+
 		boolean weNeedToCreateCountQuery = !namedCountQueryIsPresent && method.getParameters().hasPageableParameter();
 		boolean cantExtractQuery = !this.extractor.canExtractQuery();
 
@@ -165,18 +173,25 @@ final class NamedQuery extends AbstractJpaQuery {
 		TypedQuery<Long> countQuery;
 
 		if (namedCountQueryIsPresent) {
+
 			countQuery = em.createNamedQuery(countQueryName, Long.class);
+
 		} else {
-			Query query = createQuery(values);
-			String queryString = extractor.extractQueryString(query);
 
-			if (queryString == null) {
-				throw new IllegalStateException(String.format("Cannot extract query string for query %s is null!", query));
-			}
+			String countQueryString = declaredQuery.deriveCountQuery(null, countProjection).getQueryString();
 
-			countQuery = em.createQuery(QueryUtils.createCountQueryFor(queryString, countProjection), Long.class);
+			countQuery = em.createQuery(countQueryString, Long.class);
 		}
 
 		return parameterBinder.get().bind(countQuery, values, LENIENT);
 	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.query.AbstractJpaQuery#getTypeToRead()
+	 */
+	@Override
+	protected Optional<Class<?>> getTypeToRead() {
+		return declaredQuery.hasConstructorExpression() ? Optional.empty() : super.getTypeToRead();
+	}
 }

src/test/java/org/springframework/data/jpa/domain/sample/User.java

@@ -85,7 +85,10 @@ import javax.persistence.TemporalType;
 		@NamedQuery(name = "User.findByEmailAddress", //
 				query = "SELECT u FROM User u WHERE u.emailAddress = ?1"), //
 		@NamedQuery(name = "User.findByNamedQueryWithAliasInInvertedOrder", //
-				query = "SELECT u.lastname AS lastname, u.firstname AS firstname FROM User u ORDER BY u.lastname ASC") })
+				query = "SELECT u.lastname AS lastname, u.firstname AS firstname FROM User u ORDER BY u.lastname ASC"),
+		@NamedQuery(name = "User.findByNamedQueryWithConstructorExpression",
+				query = "SELECT new org.springframework.data.jpa.repository.sample.NameOnlyDto(u.firstname, u.lastname) from User u") })
+
 @NamedStoredProcedureQueries({ //
 		@NamedStoredProcedureQuery(name = "User.plus1", procedureName = "plus1inout",
 				parameters = { @StoredProcedureParameter(mode = ParameterMode.IN, name = "arg", type = Integer.class),

src/test/java/org/springframework/data/jpa/repository/UserRepositoryFinderTests.java

@@ -172,8 +172,8 @@ public class UserRepositoryFinderTests {
 	public void respectsPageableOrderOnQueryGenerateFromMethodName() throws Exception {
 		Page<User> ascending = userRepository.findByLastnameIgnoringCase(PageRequest.of(0, 10, Sort.by(ASC, "firstname")),
 				"Matthews");
-		Page<User> descending = userRepository
-				.findByLastnameIgnoringCase(PageRequest.of(0, 10, Sort.by(DESC, "firstname")), "Matthews");
+		Page<User> descending = userRepository.findByLastnameIgnoringCase(PageRequest.of(0, 10, Sort.by(DESC, "firstname")),
+				"Matthews");
 		assertThat(ascending.getTotalElements(), is(2L));
 		assertThat(descending.getTotalElements(), is(2L));
 		assertThat(ascending.getContent().get(0).getFirstname(),
@@ -223,4 +223,9 @@ public class UserRepositoryFinderTests {
 	public void rejectsStreamExecutionIfNoSurroundingTransactionActive() {
 		userRepository.findAllByCustomQueryAndStream();
 	}
+
+	@Test // DATAJPA-1334
+	public void executesNamedQueryWithConstructorExpression() {
+		userRepository.findByNamedQueryWithConstructorExpression();
+	}
 }

src/test/java/org/springframework/data/jpa/repository/sample/NameOnlyDto.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2018 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
+ *
+ *      http://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.jpa.repository.sample;
+
+// DATAJPA-1334
+class NameOnlyDto {
+
+	String firstname, lastname;
+
+	public NameOnlyDto(String firstname, String lastname) {
+		this.firstname = firstname;
+		this.lastname = lastname;
+	}
+}

src/test/java/org/springframework/data/jpa/repository/sample/UserRepository.java

@@ -553,6 +553,9 @@ public interface UserRepository
 	@Query(value = "select * from SD_User u where u.emailAddress = ?", nativeQuery = true)
 	User findByEmailNativeAddressJdbcStyleParameter(String emailAddress);
 
+	// DATAJPA-1334
+	List<NameOnlyDto> findByNamedQueryWithConstructorExpression();
+
 	interface RolesAndFirstname {
 
 		String getFirstname();