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

@@ -25,6 +25,7 @@ import org.springframework.data.jpa.provider.QueryExtractor;
 import org.springframework.data.repository.query.Parameters;
 import org.springframework.data.repository.query.QueryCreationException;
 import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.util.StringUtils;
 
 /**
  * Implementation of {@link RepositoryQuery} based on {@link javax.persistence.NamedQuery}s.
@@ -46,6 +47,7 @@ final class NamedQuery extends AbstractJpaQuery {
 	private final String countProjection;
 	private final QueryExtractor extractor;
 	private final boolean namedCountQueryIsPresent;
+	private final StringQuery declaredQuery;
 
 	/**
 	 * Creates a new {@link NamedQuery}.
@@ -79,6 +81,11 @@ final class NamedQuery extends AbstractJpaQuery {
 			LOG.warn("Finder method {} is backed by a NamedQuery" + " but contains a Pageable parameter! Sorting delivered "
 					+ "via this Pageable will not be applied!", method);
 		}
+
+		Query query = em.createNamedQuery(queryName);
+		String queryString = extractor.extractQueryString(query);
+
+		this.declaredQuery = StringUtils.hasText(queryString) ? new StringQuery(queryString) : null;
 	}
 
 	/**
@@ -157,13 +164,29 @@ final class NamedQuery extends AbstractJpaQuery {
 		TypedQuery<Long> countQuery = null;
 
 		if (namedCountQueryIsPresent) {
+
 			countQuery = em.createNamedQuery(countQueryName, Long.class);
+
 		} else {
-			Query query = createQuery(values);
-			String queryString = extractor.extractQueryString(query);
-			countQuery = em.createQuery(QueryUtils.createCountQueryFor(queryString, countProjection), Long.class);
+
+			if (declaredQuery == null) {
+				throw new IllegalStateException("Cannot derive count query without an extracted source query!");
+			}
+
+			String countQueryString = QueryUtils.createCountQueryFor(declaredQuery.getQueryString(), countProjection);
+
+			countQuery = em.createQuery(countQueryString, Long.class);
 		}
 
 		return createBinder(values).bind(countQuery);
 	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.query.AbstractJpaQuery#getTypeToRead()
+	 */
+	@Override
+	protected Class<?> getTypeToRead() {
+		return declaredQuery != null && !declaredQuery.hasConstructorExpression() ? super.getTypeToRead() : null;
+	}
 }

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

@@ -82,7 +82,10 @@ 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

@@ -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
+public 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

@@ -494,6 +494,9 @@ public interface UserRepository
 	@Query("select firstname as firstname, lastname as lastname from User u where u.firstname = 'Oliver'")
 	Map<String, Object> findMapWithNullValues();
 
+	// DATAJPA-1334
+	List<NameOnlyDto> findByNamedQueryWithConstructorExpression();
+
 	interface RolesAndFirstname {
 
 		String getFirstname();