Integrate clauses based statements with executable statements, improv…

…e documentation.

docs/cypher-parser/cypher-parser.adoc

@@ -133,7 +133,7 @@ include::../../neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-parser/src/te
 <.> The callback from step one is passed as callback to the event `ON_RETURN_ITEM` and will be called for every item
 <.> The final option instance will be applied to the parser. The statement will render to the same result as <<example-using-input,the first example>>.
 
-== Preventing certain things
+=== Preventing certain things
 
 Callbacks can of course be used to prevent things.
 Any exception thrown will halt the parsing.
@@ -208,3 +208,28 @@ include::../../neo4j-cypher-dsl-parser/src/test/java/org/neo4j/cypherdsl/parser/
 
 Changing relationship types via a filter is possible as well, but as relationships might only have one type, the number of
 usecases is smaller.
+
+
+=== Combining the parser with SDN's `CypherdslConditionExecutor`
+
+Spring Data Neo4j 6 provides `CypherdslConditionExecutor`. This is a fragment that adds the capability to execute
+statements with added conditions to a `Neo4jRepository`.
+
+Given the following repository:
+
+[source,java,indent=0,tabsize=4]
+----
+include::../../neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/src/main/java/org/neo4j/cypherdsl/examples/sdn6/movies/PeopleRepository.java[tag=additional-fragments]
+----
+<.> Allows to just add conditions to our generated queries
+<.> Provides an alternative to using @Query with strings
+
+One possible use case is presented in this service:
+
+[source,java,indent=0,tabsize=4]
+----
+include::../../neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/src/main/java/org/neo4j/cypherdsl/examples/sdn6/movies/PeopleService.java[tag=using-parser-with-spring]
+----
+<.> The condition that only people born later than 1980 is hard coded in the service.
+    An arbitrary String is than parsed into a condition and attached via `AND`.
+    Thus only valid cypher can go in there and with filters and callbacks, preconditions of that Cypher can be asserted.

neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/pom.xml

@@ -52,6 +52,13 @@
 			<version>${project.version}</version>
 		</dependency>
 
+		<!-- Only needed when using the parser feature -->
+		<dependency>
+			<groupId>org.neo4j</groupId>
+			<artifactId>neo4j-cypher-dsl-parser</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-data-neo4j</artifactId>

neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/src/main/java/org/neo4j/cypherdsl/examples/sdn6/movies/PeopleController.java

@@ -53,4 +53,10 @@ Iterable<Person> findPeopleBornInThe70tiesOr(@RequestParam(name = "name") Option
 
 		return peopleService.findPeopleBornInThe70tiesOr(optionalName);
 	}
+
+	@GetMapping("/findPeopleBornAfterThe70ties")
+	Iterable<Person> findPeopleBornAfterThe70ties(@RequestParam(name = "conditions") String additionalConditions) {
+
+		return peopleService.findPeopleBornAfterThe70tiesAnd(additionalConditions);
+	}
 }

neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/src/main/java/org/neo4j/cypherdsl/examples/sdn6/movies/PeopleService.java

@@ -25,6 +25,7 @@
 import org.neo4j.cypherdsl.core.Cypher;
 import org.neo4j.cypherdsl.core.Functions;
 // end::using-person-repo[]
+import org.neo4j.cypherdsl.parser.CypherParser;
 import org.springframework.data.domain.Example;
 // tag::using-person-repo[]
 import org.springframework.stereotype.Service;
@@ -51,6 +52,17 @@ Optional<Person> findOne(Example<Person> example) {
 		return peopleRepository.findOne(example);
 	}
 
+
+	// tag::using-parser-with-spring[]
+	Iterable<Person> findPeopleBornAfterThe70tiesAnd(String additionalConditions) {
+
+		return peopleRepository.findAll(
+			PERSON.BORN.gte(Cypher.literalOf(1980))
+				.and(CypherParser.parseExpression(additionalConditions).asCondition()) // <.>
+		);
+	}
+	// end::using-parser-with-spring[]
+
 	// tag::using-person-repo[]
 	Iterable<Person> findPeopleBornInThe70tiesOr(Optional<String> optionalName) {
 

neo4j-cypher-dsl-examples/neo4j-cypher-dsl-examples-sdn6/src/test/java/org/neo4j/cypherdsl/examples/sdn6/ApplicationIT.java

@@ -174,4 +174,16 @@ void findPeopleBornInThe70tiesOrShouldWork2(@Autowired TestRestTemplate restTemp
 		var people = exchange.getBody();
 		assertThat(people).hasSize(18);
 	}
+
+	@Test
+	@DisplayName("Using conditions pt3.")
+	void findPeopleBornAfterThe70tiesShouldWork(@Autowired TestRestTemplate restTemplate) {
+
+		var exchange = restTemplate
+			.exchange("/api/people/findPeopleBornAfterThe70ties?conditions={conditions}", HttpMethod.GET, null, new ParameterizedTypeReference<List<Person>>() {
+			}, "n.name contains \"Ricci\" OR n.name ends with 'Hirsch'");
+		assertThat(exchange.getStatusCode()).isEqualTo(HttpStatus.OK);
+		var people = exchange.getBody();
+		assertThat(people).hasSize(2);
+	}
 }

neo4j-cypher-dsl-parser/pom.xml

@@ -54,6 +54,12 @@
 			<artifactId>neo4j-cypher-javacc-parser</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>io.projectreactor</groupId>
+			<artifactId>reactor-core</artifactId>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.asciidoctor</groupId>
 			<artifactId>asciidoctorj</artifactId>
@@ -71,6 +77,12 @@
 			<artifactId>junit-jupiter</artifactId>
 			<scope>test</scope>
 		</dependency>
+
+		<dependency>
+			<groupId>org.reactivestreams</groupId>
+			<artifactId>reactive-streams</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/ClausesBasedStatement.java

@@ -60,7 +60,8 @@ public void accept(Visitor visitor) {
 		visitor.leave(this);
 	}
 
-	boolean doesReturnOrYield() {
+	@Override
+	public boolean doesReturnOrYield() {
 		if (this.clauses.isEmpty()) {
 			return false;
 		}

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/Statement.java

@@ -185,4 +185,11 @@ interface RegularQuery extends Statement {
 	 */
 	interface SingleQuery extends RegularQuery {
 	}
+
+	/**
+	 * @return True if this statement can be assured to return something.
+	 */
+	default boolean doesReturnOrYield() {
+		return this instanceof ResultStatement || this instanceof UnionQuery;
+	}
 }

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/Subquery.java

@@ -67,8 +67,7 @@ static Subquery call(Statement statement, IdentifiableElement... imports) {
 	static Subquery call(Statement statement, boolean skipAssertions, IdentifiableElement... imports) {
 
 		if (!skipAssertions) {
-			boolean clausesBasedWithReturn = statement instanceof ClausesBasedStatement && ((ClausesBasedStatement) statement).doesReturnOrYield();
-			boolean validReturn = statement instanceof ResultStatement || statement instanceof UnionQuery || clausesBasedWithReturn;
+			boolean validReturn = statement.doesReturnOrYield();
 			if (!validReturn) {
 				throw new IllegalArgumentException("Only a statement that returns elements, either via RETURN or YIELD, can be used in a subquery.");
 			}

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/SymbolicName.java

@@ -47,7 +47,7 @@
  * @since 1.0
  */
 @API(status = Status.EXPERIMENTAL, since = "1.0")
-public class SymbolicName implements Expression, IdentifiableElement {
+public final class SymbolicName implements Expression, IdentifiableElement {
 
 	private static final Map<String, SymbolicName> CACHE = Collections.synchronizedMap(new LRUCache<>(32));
 

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/executables/DefaultExecutableResultStatement.java

@@ -27,7 +27,7 @@
 import java.util.stream.Stream;
 
 import org.apiguardian.api.API;
-import org.neo4j.cypherdsl.core.ResultStatement;
+import org.neo4j.cypherdsl.core.Statement;
 import org.neo4j.driver.QueryRunner;
 import org.neo4j.driver.Record;
 import org.neo4j.driver.Result;
@@ -42,7 +42,7 @@
 @API(status = INTERNAL, since = "2021.2.1")
 class DefaultExecutableResultStatement extends DefaultExecutableStatement implements ExecutableResultStatement {
 
-	DefaultExecutableResultStatement(ResultStatement delegate) {
+	DefaultExecutableResultStatement(Statement delegate) {
 		super(delegate);
 	}
 

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/executables/DefaultReactiveExecutableResultStatement.java

@@ -25,7 +25,7 @@
 import java.util.function.Function;
 
 import org.apiguardian.api.API;
-import org.neo4j.cypherdsl.core.ResultStatement;
+import org.neo4j.cypherdsl.core.Statement;
 import org.neo4j.driver.Record;
 import org.neo4j.driver.reactive.RxQueryRunner;
 import org.reactivestreams.Publisher;
@@ -38,7 +38,7 @@
 @API(status = INTERNAL, since = "2021.2.1")
 class DefaultReactiveExecutableResultStatement extends DefaultReactiveExecutableStatement implements ReactiveExecutableResultStatement {
 
-	DefaultReactiveExecutableResultStatement(ResultStatement delegate) {
+	DefaultReactiveExecutableResultStatement(Statement delegate) {
 		super(delegate);
 	}
 

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/executables/ExecutableStatement.java

@@ -68,8 +68,8 @@ public interface ExecutableStatement {
 	 * @see #of(Statement)
 	 */
 	static ExecutableStatement makeExecutable(Statement statement) {
-		if (statement instanceof ResultStatement) {
-			return makeExecutable((ResultStatement) statement);
+		if (statement.doesReturnOrYield()) {
+			return new DefaultExecutableResultStatement(statement);
 		}
 		return new DefaultExecutableStatement(statement);
 	}

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/executables/ReactiveExecutableStatement.java

@@ -49,8 +49,8 @@ public interface ReactiveExecutableStatement extends ExecutableStatement {
 	 * @see #of(Statement)
 	 */
 	static ReactiveExecutableStatement makeExecutable(Statement statement) {
-		if (statement instanceof ResultStatement) {
-			return makeExecutable((ResultStatement) statement);
+		if (statement.doesReturnOrYield()) {
+			return new DefaultReactiveExecutableResultStatement(statement);
 		}
 		return new DefaultReactiveExecutableStatement(statement);
 	}