Read correct domain type when returning interface type from domain type hierarchy.

We now read the correct type to read (domain type) when a repository query method declares an interface type that is implemented by the domain type.

Closes #1335

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/repository/query/AbstractCassandraQuery.java

@@ -107,7 +107,7 @@ public abstract class AbstractCassandraQuery extends CassandraRepositoryQuerySup
 		CassandraReturnedType returnedType = new CassandraReturnedType(resultProcessor.getReturnedType(),
 				getOperations().getConverter().getCustomConversions());
 
-		return returnedType.isProjecting() ? returnedType.getDomainType() : returnedType.getReturnedType();
+		return returnedType.getResultType();
 	}
 
 	/**

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/repository/query/AbstractReactiveCassandraQuery.java

@@ -103,7 +103,7 @@ public abstract class AbstractReactiveCassandraQuery extends CassandraRepository
 		CassandraReturnedType returnedType = new CassandraReturnedType(resultProcessor.getReturnedType(),
 				getRequiredConverter(getReactiveCassandraOperations()).getCustomConversions());
 
-		return (returnedType.isProjecting() ? returnedType.getDomainType() : returnedType.getReturnedType());
+		return returnedType.getResultType();
 	}
 
 	/**

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/repository/query/CassandraRepositoryQuerySupport.java

@@ -19,7 +19,6 @@ import java.util.Map;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.data.cassandra.core.CassandraOperations;
 import org.springframework.data.cassandra.core.mapping.CassandraMappingContext;
 import org.springframework.data.cassandra.core.mapping.CassandraPersistentEntity;
@@ -104,7 +103,22 @@ public abstract class CassandraRepositoryQuerySupport implements RepositoryQuery
 			this.customConversions = customConversions;
 		}
 
-		boolean isProjecting() {
+		public Class<?> getResultType() {
+
+			if (isProjecting()) {
+				return returnedType.getDomainType();
+			}
+
+			Class<?> typeToRead = returnedType.getTypeToRead();
+
+			if (typeToRead == null) {
+				return returnedType.getReturnedType();
+			}
+
+			return typeToRead;
+		}
+
+		private boolean isProjecting() {
 
 			if (!this.returnedType.isProjecting()) {
 				return false;
@@ -124,13 +138,5 @@ public abstract class CassandraRepositoryQuerySupport implements RepositoryQuery
 			// Don't apply projection on Cassandra simple types
 			return !this.customConversions.isSimpleType(this.returnedType.getReturnedType());
 		}
-
-		Class<?> getDomainType() {
-			return this.returnedType.getDomainType();
-		}
-
-		Class<?> getReturnedType() {
-			return this.returnedType.getReturnedType();
-		}
 	}
 }

spring-data-cassandra/src/test/java/org/springframework/data/cassandra/repository/query/AbstractCassandraQueryUnitTests.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2023 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
+ *
+ *      https://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.cassandra.repository.query;
+
+import static org.mockito.Mockito.*;
+
+import java.util.Optional;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.data.cassandra.core.CassandraOperations;
+import org.springframework.data.cassandra.core.convert.MappingCassandraConverter;
+import org.springframework.data.cassandra.core.mapping.CassandraMappingContext;
+import org.springframework.data.cassandra.repository.CassandraRepository;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
+import org.springframework.data.repository.core.support.DefaultRepositoryMetadata;
+
+/**
+ * Unit tests for {@link AbstractCassandraQuery}.
+ *
+ * @author Mark Paluch
+ */
+public class AbstractCassandraQueryUnitTests {
+
+	CassandraMappingContext context = new CassandraMappingContext();
+	CassandraOperations operations = mock(CassandraOperations.class);
+
+	@BeforeEach
+	void setUp() {
+		when(operations.getConverter()).thenReturn(new MappingCassandraConverter(context));
+	}
+
+	@Test
+	void shouldResolveDomainTypeForReturnedInterfaceInHierarchy() throws Exception {
+
+		DefaultRepositoryMetadata metadata = new DefaultRepositoryMetadata(MyRepository.class);
+
+		ProjectionFactory factory = new SpelAwareProxyProjectionFactory();
+		CassandraQueryMethod method = new CassandraQueryMethod(MyRepository.class.getMethod("findBy"), metadata, factory,
+				context);
+
+		PartTreeCassandraQuery cq = new PartTreeCassandraQuery(method, operations);
+		cq.execute(new Object[0]);
+
+		verify(operations).select(any(com.datastax.oss.driver.api.core.cql.Statement.class), eq(MyClass.class));
+	}
+
+	interface MyInterface {
+
+	}
+
+	static class MyClass implements MyInterface {
+
+	}
+
+	interface MyRepository extends CassandraRepository<MyClass, String> {
+
+		Optional<MyInterface> findBy();
+	}
+}