Add Streamable support to AOT repositories.

Closes #1620

Author: christophstrobl

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/repository/aot/CassandraCodeBlocks.java

@@ -42,6 +42,7 @@
 import org.springframework.data.javapoet.TypeNames;
 import org.springframework.data.repository.aot.generate.AotQueryMethodGenerationContext;
 import org.springframework.data.repository.aot.generate.MethodReturn;
+import org.springframework.data.util.Streamable;
 import org.springframework.javapoet.CodeBlock;
 import org.springframework.javapoet.CodeBlock.Builder;
 import org.springframework.javapoet.TypeName;
@@ -706,16 +707,22 @@ CodeBlock build() {
 					conversionMethod = "convertOne";
 				}
 
+				CodeBlock result = CodeBlock.of("$L($L, $T.class)", conversionMethod, execution.build(), actualReturnType);
+				if (queryMethod.getReturnType().getType().equals(Streamable.class)) {
+					result = CodeBlock.of("$T.of($L)", Streamable.class, result);
+				}
+
 				builder.addStatement(returnBuilder //
-						.optional("($T) $L($L, $T.class)", methodReturn.getTypeName(), conversionMethod, execution.build(),
-								actualReturnType) //
+						.optional("($T) $L", methodReturn.getTypeName(), result) //
 						.build());
 			} else {
 
 				CodeBlock executionBlock = execution.build();
 
 				if (query.isCount()) {
 					returnBuilder.whenPrimitiveOrBoxed(Integer.class, "(int) $L", executionBlock);
+				} else if (queryMethod.getReturnType().getType().equals(Streamable.class)) {
+					executionBlock = CodeBlock.of("$T.of($L)", Streamable.class, executionBlock);
 				}
 
 				builder.addStatement(returnBuilder.optional(executionBlock) //

spring-data-cassandra/src/test/java/org/springframework/data/cassandra/repository/aot/CassandraRepositoryContributorIntegrationTests.java

@@ -45,12 +45,14 @@
 import org.springframework.data.cassandra.repository.support.AbstractSpringDataEmbeddedCassandraIntegrationTest;
 import org.springframework.data.cassandra.repository.support.IntegrationTestConfig;
 import org.springframework.data.domain.Limit;
+import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.ScoringFunction;
 import org.springframework.data.domain.Slice;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Vector;
 import org.springframework.data.domain.Window;
+import org.springframework.data.util.Streamable;
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
 
 import com.datastax.oss.driver.api.core.CqlIdentifier;
@@ -196,6 +198,24 @@ void shouldApplySorting() {
 				.containsSequence("Flynn (Walter Jr.)", "Skyler", "Walter");
 	}
 
+	@Test // GH-1620
+	void shouldConvertResultToStreamable() {
+
+		assertThat(fragment.streamByLastname("White", Sort.by("firstname")))
+			.isInstanceOf(Streamable.class) //
+			.extracting(Person::getFirstname) //
+			.containsExactly("Flynn (Walter Jr.)", "Skyler", "Walter");
+	}
+
+	@Test // GH-1620
+	void shouldConvertResultToStreamableWhenPageableParameterIsUsed() {
+
+		assertThat(fragment.streamByLastname("White", PageRequest.of(0, 2, Sort.by("firstname"))))
+			.isInstanceOf(Streamable.class) //
+			.extracting(Person::getFirstname) //
+			.containsExactly("Flynn (Walter Jr.)", "Skyler");
+	}
+
 	@Test // GH-1566
 	void shouldFindByFirstnameContains() {
 

spring-data-cassandra/src/test/java/org/springframework/data/cassandra/repository/aot/PersonRepository.java

@@ -41,6 +41,7 @@
 
 import com.datastax.oss.driver.api.core.DefaultConsistencyLevel;
 import com.datastax.oss.driver.api.core.cql.ResultSet;
+import org.springframework.data.util.Streamable;
 
 /**
  * AOT repository interface for {@link Person} entities.
@@ -63,6 +64,10 @@ public interface PersonRepository extends CrudRepository<Person, String> {
 
 	List<Person> findByLastname(String lastname, Sort sort);
 
+	Streamable<Person> streamByLastname(String lastname, Sort sort);
+
+	Streamable<Person> streamByLastname(String lastname, Pageable pageable);
+
 	List<Person> findByLastnameOrderByFirstnameAsc(String lastname);
 
 	Person findByFirstnameStartsWith(String prefix);