DATACASS-611 - Add query derivation for delete queries.

We now support query derivation for delete queries using delete…By in method declarations.

interface PersonRepository extends Repository<Person, String> {

  void deleteWithoutResultByLastname(String lastname);

  boolean deleteByLastname(String lastname);
}

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

@@ -146,6 +146,8 @@ public abstract class AbstractCassandraQuery extends CassandraRepositoryQuerySup
 			return ((statement, type) -> new SingleEntityExecution(getOperations(), false).execute(statement, Long.class));
 		} else if (isExistsQuery()) {
 			return new ExistsExecution(getOperations());
+		} else if (isModifyingQuery()) {
+			return ((statement, type) -> getOperations().getCqlOperations().queryForResultSet(statement).wasApplied());
 		} else {
 			return new SingleEntityExecution(getOperations(), isLimiting());
 		}
@@ -174,4 +176,12 @@ public abstract class AbstractCassandraQuery extends CassandraRepositoryQuerySup
 	 * @since 2.0.4
 	 */
 	protected abstract boolean isLimiting();
+
+	/**
+	 * Returns whether the query is a modifying query.
+	 *
+	 * @return a boolean value indicating whether the query is a modifying query.
+	 * @since 2.2
+	 */
+	protected abstract boolean isModifyingQuery();
 }

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

@@ -20,6 +20,7 @@ import reactor.core.publisher.Mono;
 
 import org.reactivestreams.Publisher;
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.cassandra.ReactiveResultSet;
 import org.springframework.data.cassandra.core.CassandraOperations;
 import org.springframework.data.cassandra.core.ReactiveCassandraOperations;
 import org.springframework.data.cassandra.core.convert.CassandraConverter;
@@ -151,6 +152,9 @@ public abstract class AbstractReactiveCassandraQuery extends CassandraRepository
 					Long.class));
 		} else if (isExistsQuery()) {
 			return new ExistsExecution(getReactiveCassandraOperations());
+		} else if (isModifyingQuery()) {
+			return (statement, type) -> getReactiveCassandraOperations().getReactiveCqlOperations()
+					.queryForResultSet(statement).map(ReactiveResultSet::wasApplied);
 		} else {
 			return new SingleEntityExecution(getReactiveCassandraOperations(), isLimiting());
 		}
@@ -180,6 +184,14 @@ public abstract class AbstractReactiveCassandraQuery extends CassandraRepository
 	 */
 	protected abstract boolean isLimiting();
 
+	/**
+	 * Returns whether the query is a modifying query.
+	 *
+	 * @return a boolean value indicating whether the query is a modifying query.
+	 * @since 2.2
+	 */
+	protected abstract boolean isModifyingQuery();
+
 	private static CassandraConverter getRequiredConverter(ReactiveCassandraOperations operations) {
 
 		Assert.notNull(operations, "ReactiveCassandraOperations must not be null");

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

@@ -104,6 +104,10 @@ public class PartTreeCassandraQuery extends AbstractCassandraQuery {
 			return getQueryStatementCreator().exists(getStatementFactory(), getTree(), parameterAccessor);
 		}
 
+		if (getTree().isDelete()) {
+			return getQueryStatementCreator().delete(getStatementFactory(), getTree(), parameterAccessor);
+		}
+
 		return getQueryStatementCreator().select(getStatementFactory(), getTree(), parameterAccessor,
 				getQueryMethod().getResultProcessor());
 	}
@@ -131,4 +135,12 @@ public class PartTreeCassandraQuery extends AbstractCassandraQuery {
 	protected boolean isLimiting() {
 		return getTree().isLimiting();
 	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.cassandra.repository.query.AbstractCassandraQuery#isModifyingQuery()
+	 */
+	@Override
+	protected boolean isModifyingQuery() {
+		return getTree().isDelete();
+	}
 }

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

@@ -118,6 +118,32 @@ class QueryStatementCreator {
 		return doWithQuery(parameterAccessor, tree, function);
 	}
 
+	/**
+	 * Create a {@literal DELETE} {@link Statement} from a {@link PartTree} and apply query options for delete query
+	 * execution.
+	 *
+	 * @param statementFactory must not be {@literal null}.
+	 * @param tree must not be {@literal null}.
+	 * @param parameterAccessor must not be {@literal null}.
+	 * @return the {@literal DELETE} {@link Statement}.
+	 * @since 2.2
+	 */
+	Statement delete(StatementFactory statementFactory, PartTree tree, CassandraParameterAccessor parameterAccessor) {
+
+		Function<Query, Statement> function = query -> {
+
+			RegularStatement statement = statementFactory.delete(query, requirePersistentEntity());
+
+			if (LOG.isDebugEnabled()) {
+				LOG.debug(String.format("Created query [%s].", statement));
+			}
+
+			return statement;
+		};
+
+		return doWithQuery(parameterAccessor, tree, function);
+	}
+
 	/**
 	 * Create a {@literal SELECT} {@link Statement} from a {@link PartTree} and apply query options for exists query
 	 * execution. Limit results to a single row.

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

@@ -17,10 +17,13 @@ package org.springframework.data.cassandra.repository.query;
 
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import java.util.List;
 
+import org.reactivestreams.Publisher;
+
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.data.cassandra.core.ReactiveCassandraOperations;
@@ -190,7 +193,6 @@ interface ReactiveCassandraQueryExecution {
 		 * (non-Javadoc)
 		 * @see org.springframework.data.cassandra.repository.query.ReactiveCassandraQueryExecution#execute(java.lang.String, java.lang.Class)
 		 */
-		@SuppressWarnings("ConstantConditions")
 		@Override
 		public Object execute(Statement statement, Class<?> type) {
 			return converter.convert(delegate.execute(statement, type));
@@ -222,6 +224,16 @@ interface ReactiveCassandraQueryExecution {
 				return source;
 			}
 
+			if (returnedType.getReturnedType().equals(Void.class)) {
+				if (source instanceof Mono) {
+					return ((Mono<?>) source).then();
+				}
+
+				if (source instanceof Publisher) {
+					return Flux.from((Publisher<?>) source).then();
+				}
+			}
+
 			if (returnedType.isInstance(source)) {
 				return source;
 			}

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

@@ -104,6 +104,10 @@ public class ReactivePartTreeCassandraQuery extends AbstractReactiveCassandraQue
 			return getQueryStatementCreator().exists(getStatementFactory(), getTree(), parameterAccessor);
 		}
 
+		if (getTree().isDelete()) {
+			return getQueryStatementCreator().delete(getStatementFactory(), getTree(), parameterAccessor);
+		}
+
 		return getQueryStatementCreator().select(getStatementFactory(), getTree(), parameterAccessor,
 				getQueryMethod().getResultProcessor());
 	}
@@ -131,4 +135,12 @@ public class ReactivePartTreeCassandraQuery extends AbstractReactiveCassandraQue
 	protected boolean isLimiting() {
 		return getTree().isLimiting();
 	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.cassandra.repository.query.AbstractCassandraQuery#isModifyingQuery()
+	 */
+	@Override
+	protected boolean isModifyingQuery() {
+		return getTree().isDelete();
+	}
 }

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

@@ -140,4 +140,12 @@ public class ReactiveStringBasedCassandraQuery extends AbstractReactiveCassandra
 	protected boolean isLimiting() {
 		return false;
 	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.cassandra.repository.query.AbstractCassandraQuery#isModifyingQuery()
+	 */
+	@Override
+	protected boolean isModifyingQuery() {
+		return false;
+	}
 }

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

@@ -134,4 +134,12 @@ public class StringBasedCassandraQuery extends AbstractCassandraQuery {
 	protected boolean isLimiting() {
 		return false;
 	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.cassandra.repository.query.AbstractCassandraQuery#isModifyingQuery()
+	 */
+	@Override
+	protected boolean isModifyingQuery() {
+		return false;
+	}
 }

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

@@ -343,6 +343,23 @@ public class QueryDerivationIntegrationTests extends AbstractSpringDataEmbeddedC
 		assertThat(count).isEqualTo(3);
 	}
 
+	@Test // DATACASS-611
+	public void shouldDeleteRecords() {
+
+		personRepository.deleteByLastname("White");
+
+		assertThat(personRepository.countByLastname("White")).isZero();
+	}
+
+	@Test // DATACASS-611
+	public void shouldDeleteRecordsWithWasApplied() {
+
+		boolean deleted = personRepository.deleteByLastname("White");
+
+		assertThat(deleted).isTrue();
+		assertThat(personRepository.countByLastname("White")).isZero();
+	}
+
 	@Test // DATACASS-512
 	public void shouldApplyExistsProjection() {
 
@@ -383,6 +400,10 @@ public class QueryDerivationIntegrationTests extends AbstractSpringDataEmbeddedC
 
 		long countByLastname(String lastname);
 
+		boolean deleteByLastname(String lastname);
+
+		void deleteVoidByLastname(String lastname);
+
 		boolean existsByLastname(String lastname);
 
 		Slice<Person> findAllSlicedByLastname(String lastname, Pageable pageable);

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

@@ -15,19 +15,19 @@
  */
 package org.springframework.data.cassandra.repository;
 
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Set;
-
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-
 import org.reactivestreams.Publisher;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.BeanFactory;
@@ -132,11 +132,10 @@ public class ReactiveCassandraRepositoryIntegrationTests extends AbstractKeyspac
 		repository.findByLastname(dave.getLastname()).as(StepVerifier::create).expectNextCount(2).verifyComplete();
 	}
 
-	@Test //DATACASS-529
+	@Test // DATACASS-529
 	public void shouldFindSliceByLastName() {
 		repository.findByLastname(carter.getLastname(), CassandraPageRequest.first(1)).as(StepVerifier::create)
-				.expectNextMatches(users -> users.getSize() == 1 && users.hasNext())
-				.verifyComplete();
+				.expectNextMatches(users -> users.getSize() == 1 && users.hasNext()).verifyComplete();
 	}
 
 	@Test // DATACASS-529
@@ -193,8 +192,7 @@ public class ReactiveCassandraRepositoryIntegrationTests extends AbstractKeyspac
 				.verifyComplete();
 
 		groupRepostitory.findByIdGroupnameAndIdHashPrefix("Simpsons", "hash", Sort.by("id.username").descending())
-				.as(StepVerifier::create)
-				.expectNext(new Group(key2), new Group(key1)) //
+				.as(StepVerifier::create).expectNext(new Group(key2), new Group(key1)) //
 				.verifyComplete();
 	}
 
@@ -208,6 +206,22 @@ public class ReactiveCassandraRepositoryIntegrationTests extends AbstractKeyspac
 		repository.countQueryByLastname("None").as(StepVerifier::create).expectNext(0L).verifyComplete();
 	}
 
+	@Test // DATACASS-611
+	public void shouldDeleteRecords() {
+
+		repository.deleteVoidById(dave.getId()).as(StepVerifier::create).verifyComplete();
+
+		repository.countByLastname("Matthews").as(StepVerifier::create).expectNext(1L).verifyComplete();
+	}
+
+	@Test // DATACASS-611
+	public void shouldDeleteRecordsReturingWasApplied() {
+
+		repository.deleteAllById(dave.getId()).as(StepVerifier::create).expectNext(true).verifyComplete();
+
+		repository.countByLastname("Matthews").as(StepVerifier::create).expectNext(1L).verifyComplete();
+	}
+
 	@Test // DATACASS-512
 	public void shouldApplyExistsProjection() {
 
@@ -232,6 +246,10 @@ public class ReactiveCassandraRepositoryIntegrationTests extends AbstractKeyspac
 
 		Mono<Long> countByLastname(String lastname);
 
+		Mono<Boolean> deleteAllById(String lastname);
+
+		Mono<Void> deleteVoidById(String lastname);
+
 		Mono<Boolean> existsByLastname(String lastname);
 
 		@Query("SELECT * FROM users WHERE lastname = ?0")

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

@@ -30,6 +30,7 @@ import org.junit.rules.ExpectedException;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
+
 import org.springframework.data.cassandra.core.CassandraOperations;
 import org.springframework.data.cassandra.core.convert.CassandraConverter;
 import org.springframework.data.cassandra.core.convert.MappingCassandraConverter;
@@ -215,6 +216,15 @@ public class PartTreeCassandraQueryUnitTests {
 		assertThat(statement.toString()).isEqualTo("SELECT COUNT(1) FROM person;");
 	}
 
+	@Test // DATACASS-611
+	public void shouldCreateDeleteQuery() {
+
+		Statement statement = deriveQueryFromMethod(Repo.class, "deleteAllByLastname", new Class[] { String.class },
+				"Walter");
+
+		assertThat(statement.toString()).isEqualTo("DELETE FROM person WHERE lastname='Walter';");
+	}
+
 	@Test // DATACASS-512
 	public void shouldCreateExistsQuery() {
 
@@ -295,6 +305,8 @@ public class PartTreeCassandraQueryUnitTests {
 
 		long countBy();
 
+		boolean deleteAllByLastname(String lastname);
+
 		boolean existsBy();
 
 		@AllowFiltering

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

@@ -141,6 +141,15 @@ public class ReactivePartTreeCassandraQueryUnitTests {
 		assertThat(statement.toString()).isEqualTo("SELECT COUNT(1) FROM person;");
 	}
 
+	@Test // DATACASS-611
+	public void shouldCreateDeleteQuery() {
+
+		Statement statement = deriveQueryFromMethod(PartTreeCassandraQueryUnitTests.Repo.class, "deleteAllByLastname",
+				new Class[] { String.class }, "Walter");
+
+		assertThat(statement.toString()).isEqualTo("DELETE FROM person WHERE lastname='Walter';");
+	}
+
 	@Test // DATACASS-512
 	public void shouldCreateExistsQuery() {
 
@@ -202,6 +211,8 @@ public class ReactivePartTreeCassandraQueryUnitTests {
 
 		Mono<Long> countBy();
 
+		Mono<Boolean> deleteAllByLastname(String lastname);
+
 		Mono<Boolean> existsBy();
 
 		@Consistency(ConsistencyLevel.LOCAL_ONE)

src/main/asciidoc/new-features.adoc

@@ -13,6 +13,7 @@ This chapter summarizes changes and new features for each release.
 * Optimistic Locking support.
 * Auditing via `@EnableCassandraAuditing`.
 * Idempotency support in `@Query` annotation.
+* Query derivation for <<cassandra.repositories.queries.delete,`DELETE` queries>>.
 
 [[new-features.2-1-0]]
 == What's new in Spring Data for Apache Cassandra 2.1

src/main/asciidoc/reference/cassandra-repositories.adoc

@@ -282,6 +282,25 @@ lower / upper bounds (`>` / `>=` & `<` / `<=`) according to `Range`
 
 |===
 
+[[cassandra.repositories.queries.delete]]
+== Repository Delete Queries
+
+The keywords in the preceding table can be used in conjunction with `delete…By` to create queries that delete matching documents.
+
+====
+[source,java]
+----
+interface PersonRepository extends Repository<Person, String> {
+
+  void deleteWithoutResultByLastname(String lastname);
+
+  boolean deleteByLastname(String lastname);
+}
+----
+====
+
+Delete queries return whether the query was applied or terminate without returning a value using `void`.
+
 include::../{spring-data-commons-docs}/repository-projections.adoc[leveloffset=+2]
 
 [[cassandra.repositories.queries.options]]
@@ -297,6 +316,7 @@ The declared consistency level is applied to the query each time it is executed.
 The following example sets the consistency level to `ConsistencyLevel.LOCAL_ONE`:
 
 ====
+[source,java]
 ----
 public interface PersonRepository extends CrudRepository<Person, String> {