GH-2681 - Add anyOf / allOf to SpEL.

Currently we only have the literals clause to render an arbitrary string into a custom Cypher statement.
Although one could prepare the string upfront manually and joining multiple strings on | or &
and pass this to the query method, it would be more convenient to add one or two functions directly.

Namely those functions will be
anyOf : renders input ["a","b", ..] to A|B|..
allOf : renders input ["a","b", ..] to A&B&..
The usage would be MATCH (n::#{allOf(#labels)}) RETURN n, for example.

Closes #2681

Author: meistermeier

src/main/asciidoc/appendix/custom-queries.adoc

@@ -418,11 +418,16 @@ public interface MyPersonRepository extends Neo4jRepository<Person, Long> {
 <.> A `Pageable` has always the name `pageable` inside the SpEL context.
 <.> A `Sort` has always the name `sort` inside the SpEL context.
 
+[[spel-extensions]]
+=== Spring Expression Language extensions
+
+[[literal-extension]]
+==== Literal extension
+
 The `literal` extension can be used to make things like labels or relationship-types "dynamic" in custom queries.
 Neither labels nor relationship types can be parameterized in Cypher, so they must be given literal.
 
 [source,java]
-[[literal-extension]]
 .literal-Extension
 ----
 interface BaseClassRepository extends Neo4jRepository<Inheritance.BaseClass, Long> {
@@ -438,6 +443,25 @@ If you pass in `SomeLabel` as a parameter to the method, `MATCH (n:``SomeLabel``
 will be generated. Ticks have been added to correctly escape values. SDN won't do this
 for you as this is probably not what you want in all cases.
 
+[[list-extensions]]
+==== List extensions
+
+For more than one value there are `allOf` and `anyOf` in place that would render
+either a `&` or `|` concatenated list of all values.
+
+[source,java]
+.List extensions
+----
+interface BaseClassRepository extends Neo4jRepository<Inheritance.BaseClass, Long> {
+
+    @Query("MATCH (n:`:#{allOf(#label)}`) RETURN n")
+    List<Inheritance.BaseClass> findByLabels(List<String> labels);
+
+    @Query("MATCH (n:`:#{anyOf(#label)}`) RETURN n")
+    List<Inheritance.BaseClass> findByLabels(List<String> labels);
+}
+----
+
 === Referring to Labels
 
 You already know how to map a Node to a domain object:

src/main/java/org/springframework/data/neo4j/repository/query/Neo4jSpelSupport.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.neo4j.repository.query;
 
+import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.Locale;
 import java.util.Map;
@@ -23,7 +24,9 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import org.apache.commons.logging.LogFactory;
 import org.apiguardian.api.API;
+import org.springframework.core.log.LogAccessor;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.neo4j.core.mapping.CypherGenerator;
@@ -49,8 +52,12 @@
 public final class Neo4jSpelSupport {
 
 	public static String FUNCTION_LITERAL = "literal";
+	public static String FUNCTION_ANY_OF = "anyOf";
+	public static String FUNCTION_ALL_OF = "allOf";
 	public static String FUNCTION_ORDER_BY = "orderBy";
 
+	private static final LogAccessor LOG = new LogAccessor(LogFactory.getLog(Neo4jSpelSupport.class));
+
 	/**
 	 * Takes {@code arg} and tries to either extract a {@link Sort sort} from it or cast it to a sort.  That sort is
 	 * than past to the {@link CypherGenerator} that renders a valid order by fragment which replaces the SpEL placeholder
@@ -87,6 +94,34 @@ public static LiteralReplacement literal(@Nullable Object arg) {
 		return literalReplacement;
 	}
 
+	public static LiteralReplacement anyOf(@Nullable Object arg) {
+		return labels(arg, "|");
+	}
+
+	public static LiteralReplacement allOf(@Nullable Object arg) {
+		return labels(arg, "&");
+	}
+
+	private static LiteralReplacement labels(@Nullable Object arg, String joinOn) {
+		return StringBasedLiteralReplacement
+				.withTargetAndValue(LiteralReplacement.Target.UNSPECIFIED,
+						arg == null ? "" : joinStrings(arg, joinOn)
+				);
+	}
+
+	private static String joinStrings(Object arg, String joinOn) {
+		if (arg instanceof Collection) {
+			return ((Collection<?>) arg).stream().map(Object::toString).collect(Collectors.joining(joinOn));
+		}
+
+		// we are so kind and also accept plain strings instead of collection<string>
+		if (arg instanceof String) {
+			return (String) arg;
+		}
+
+		throw new IllegalArgumentException(
+				String.format("Cannot process argument %s. Please note that only Collection<String> and String are supported types.", arg));
+	}
 	/**
 	 * A marker interface that indicates a literal replacement in a query instead of a parameter replacement. This
 	 * comes in handy in places where non-parameterizable things should be created dynamic, for example matching on

src/main/java/org/springframework/data/neo4j/repository/support/Neo4jEvaluationContextExtension.java

@@ -45,12 +45,15 @@ public String getExtensionId() {
 
 	@Override
 	public Map<String, Function> getFunctions() {
-
 		Map<String, Function> functions = new HashMap<>();
 		functions.put(Neo4jSpelSupport.FUNCTION_ORDER_BY, new Function(ReflectionUtils
 				.findRequiredMethod(Neo4jSpelSupport.class, Neo4jSpelSupport.FUNCTION_ORDER_BY, Object.class)));
 		functions.put(Neo4jSpelSupport.FUNCTION_LITERAL, new Function(ReflectionUtils
 				.findRequiredMethod(Neo4jSpelSupport.class, Neo4jSpelSupport.FUNCTION_LITERAL, Object.class)));
+		functions.put(Neo4jSpelSupport.FUNCTION_ANY_OF, new Function(ReflectionUtils
+				.findRequiredMethod(Neo4jSpelSupport.class, Neo4jSpelSupport.FUNCTION_ANY_OF, Object.class)));
+		functions.put(Neo4jSpelSupport.FUNCTION_ALL_OF, new Function(ReflectionUtils
+				.findRequiredMethod(Neo4jSpelSupport.class, Neo4jSpelSupport.FUNCTION_ALL_OF, Object.class)));
 
 		return functions;
 	}

src/test/java/org/springframework/data/neo4j/integration/imperative/RepositoryIT.java

@@ -3799,6 +3799,29 @@ void findByDynamicLabel(@Autowired BaseClassRepository baseClassRepository) {
 					.first().isInstanceOf(Inheritance.ConcreteClassB.class)
 					.extracting(Inheritance.BaseClass::getName)
 					.isEqualTo("cc2");
+
+			List<String> labels = new ArrayList<>();
+			labels.add("ConcreteClassA");
+			labels.add("ConcreteClassB");
+
+			assertThat(baseClassRepository.findByOrLabels(labels)).hasSize(2)
+					.hasOnlyElementsOfTypes(Inheritance.ConcreteClassA.class, Inheritance.ConcreteClassB.class)
+					.extracting(Inheritance.BaseClass::getName)
+					.containsExactlyInAnyOrder("cc1", "cc2");
+
+			assertThat(baseClassRepository.findByAndLabels(labels)).hasSize(0);
+
+			String labelsString = "ConcreteClassA";
+			assertThat(baseClassRepository.findByAndLabels(labelsString)).hasSize(1)
+					.first().isInstanceOf(Inheritance.ConcreteClassA.class)
+					.extracting(Inheritance.BaseClass::getName)
+					.isEqualTo("cc1");
+
+			assertThatExceptionOfType(RuntimeException.class).isThrownBy(() -> baseClassRepository.findByAndLabels(1))
+					.havingRootCause()
+					.isInstanceOf(IllegalArgumentException.class)
+					.withMessageContaining("Cannot process argument");
+
 		}
 
 		@Test
@@ -4442,6 +4465,12 @@ interface BaseClassRepository extends Neo4jRepository<Inheritance.BaseClass, Lon
 
 		@Query("MATCH (n::#{literal(#label)}) RETURN n")
 		List<Inheritance.BaseClass> findByLabel(@Param("label") String label);
+
+		@Query("MATCH (n::#{anyOf(#label)}) RETURN n")
+		List<Inheritance.BaseClass> findByOrLabels(@Param("label") List<String> labels);
+
+		@Query("MATCH (n::#{allOf(#label)}) RETURN n")
+		List<Inheritance.BaseClass> findByAndLabels(@Param("label") Object labels);
 	}
 
 	interface SuperBaseClassRepository extends Neo4jRepository<Inheritance.SuperBaseClass, Long> {