Align OffsetScrolling to zero-based indexes.

OffsetScrollPosition is now 0-based instead of 1-based. We differentiate between ScrollPosition.offset() as initial position and ScrollPosition.offset(0) pointing to the first returned element.

Remove unused variable.

Closes #2890
Original pull request: #2891

Author: mp911de

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

@@ -244,7 +244,9 @@ private QueryFragments createQueryFragments(@Nullable Condition condition, Sort
 
 				queryFragments.setRequiresReverseSort(keysetScrollPosition.scrollsBackward());
 			} else if (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) {
-				queryFragments.setSkip(offsetScrollPosition.getOffset());
+				if (!offsetScrollPosition.isInitial()) {
+					queryFragments.setSkip(offsetScrollPosition.getOffset() + 1);
+				}
 				queryFragments.setLimit(limitModifier.apply(pagingParameter.isUnpaged() ? maxResults.intValue() : pagingParameter.getPageSize()));
 			}
 

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

@@ -170,7 +170,7 @@ public Window<R> scroll(ScrollPosition scrollPosition) {
 
 		var skip = scrollPosition.isInitial()
 				? 0
-				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset()
+				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset() + 1
 				: 0;
 
 		Condition condition = scrollPosition instanceof KeysetScrollPosition keysetScrollPosition

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

@@ -90,7 +90,7 @@ final Window<R> scroll(ScrollPosition scrollPosition, List<R> rawResult, Neo4jPe
 
 		var skip = scrollPosition.isInitial()
 				? 0
-				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset()
+				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset() + 1
 				: 0;
 
 		var scrollDirection = scrollPosition instanceof KeysetScrollPosition keysetScrollPosition ? keysetScrollPosition.getDirection() : ScrollPosition.Direction.FORWARD;

src/main/java/org/springframework/data/neo4j/repository/query/Neo4jQuerySupport.java

@@ -285,7 +285,6 @@ final Window<?> createWindow(ResultProcessor resultProcessor, boolean incrementL
 		var domainType = resultProcessor.getReturnedType().getDomainType();
 		var neo4jPersistentEntity = mappingContext.getPersistentEntity(domainType);
 		var limit = orderBy.getQueryFragments().getLimit().intValue() - (incrementLimit ? 1 : 0);
-		var conversionService = mappingContext.getConversionService();
 		var scrollPosition = parameterAccessor.getScrollPosition();
 
 		var scrollDirection = scrollPosition instanceof KeysetScrollPosition keysetScrollPosition ? keysetScrollPosition.getDirection() : Direction.FORWARD;
@@ -295,7 +294,7 @@ final Window<?> createWindow(ResultProcessor resultProcessor, boolean incrementL
 
 		return Window.from(getSubList(rawResult, limit, scrollDirection), v -> {
 			if (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) {
-				return offsetScrollPosition.advanceBy(v + limit);
+				return offsetScrollPosition.advanceBy(v);
 			} else {
 				var accessor = neo4jPersistentEntity.getPropertyAccessor(rawResult.get(v));
 				var keys = new LinkedHashMap<String, Object>();

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

@@ -273,7 +273,7 @@ static QueryFragmentsAndParameters forConditionWithScrollPosition(Neo4jPersisten
 		if (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) {
 			skip = offsetScrollPosition.isInitial()
 					? 0
-					: offsetScrollPosition.getOffset();
+					: offsetScrollPosition.getOffset() + 1;
 
 			return forCondition(entityMetaData, condition, null, sort, null, limit, skip, includeField);
 		}

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

@@ -171,7 +171,7 @@ public Mono<Window<R>> scroll(ScrollPosition scrollPosition) {
 
 		var skip = scrollPosition.isInitial()
 				? 0
-				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset()
+				: (scrollPosition instanceof OffsetScrollPosition offsetScrollPosition) ? offsetScrollPosition.getOffset() + 1
 				: 0;
 
 		Condition condition = scrollPosition instanceof KeysetScrollPosition keysetScrollPosition

src/test/java/org/springframework/data/neo4j/integration/imperative/QuerydslNeo4jPredicateExecutorIT.java

@@ -137,15 +137,15 @@ void scrollByExampleWithNoOffset(@Autowired QueryDSLPersonRepository repository)
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 
-		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(0)));
+		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset()));
 
 		assertThat(peopleWindow.getContent()).extracting(Person::getFirstName)
 				.containsExactlyInAnyOrder("Helge");
 
 		assertThat(peopleWindow.isLast()).isFalse();
 		assertThat(peopleWindow.hasNext()).isTrue();
 
-		assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(1));
+		assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(0));
 	}
 
 	@Test
@@ -154,14 +154,14 @@ void scrollByExampleWithOffset(@Autowired QueryDSLPersonRepository repository) {
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 
-		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(1)));
+		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(0)));
 
 		assertThat(peopleWindow.getContent()).extracting(Person::getFirstName)
 				.containsExactlyInAnyOrder("Bela");
 
 		assertThat(peopleWindow.isLast()).isTrue();
 
-		assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(2));
+		assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(1));
 	}
 
 	@Test
@@ -170,7 +170,7 @@ void scrollByExampleWithContinuingOffset(@Autowired QueryDSLPersonRepository rep
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 
-		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(0)));
+		Window<Person> peopleWindow = repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset()));
 		ScrollPosition currentPosition = peopleWindow.positionAt(peopleWindow.getContent().get(0));
 		peopleWindow = repository.findBy(predicate, q -> q.limit(1).scroll(currentPosition));
 

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

@@ -2923,7 +2923,7 @@ void scrollByExample(@Autowired PersonRepository repository) {
 
 			Example<PersonWithAllConstructor> example = Example.of(sameValuePerson,
 					ExampleMatcher.matchingAll().withIgnoreNullValues());
-			Window<PersonWithAllConstructor> person = repository.findBy(example, q -> q.sortBy(Sort.by("name")).limit(1).scroll(ScrollPosition.offset(0)));
+			Window<PersonWithAllConstructor> person = repository.findBy(example, q -> q.sortBy(Sort.by("name")).limit(1).scroll(ScrollPosition.offset()));
 
 			assertThat(person).isNotNull();
 			assertThat(person.getContent().get(0)).isEqualTo(person1);

src/test/java/org/springframework/data/neo4j/integration/reactive/ReactiveQuerydslNeo4jPredicateExecutorIT.java

@@ -196,7 +196,7 @@ void scrollByExampleWithNoOffset(@Autowired QueryDSLPersonRepository repository)
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 
-		repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(0)))
+		repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset()))
 				.as(StepVerifier::create)
 				.expectNextMatches(peopleWindow -> {
 
@@ -206,7 +206,7 @@ void scrollByExampleWithNoOffset(@Autowired QueryDSLPersonRepository repository)
 					assertThat(peopleWindow.isLast()).isFalse();
 					assertThat(peopleWindow.hasNext()).isTrue();
 
-					assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(1));
+					assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(0));
 					return true;
 				}).verifyComplete();
 	}
@@ -217,14 +217,14 @@ void scrollByExampleWithOffset(@Autowired QueryDSLPersonRepository repository) {
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 
-		repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(1)))
+		repository.findBy(predicate, q -> q.limit(1).sortBy(Sort.by("firstName").descending()).scroll(ScrollPosition.offset(0)))
 				.as(StepVerifier::create)
 				.expectNextMatches(peopleWindow -> {
 					assertThat(peopleWindow.getContent()).extracting(Person::getFirstName)
 							.containsExactlyInAnyOrder("Bela");
 
 					assertThat(peopleWindow.isLast()).isTrue();
-					assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(2));
+					assertThat(peopleWindow.positionAt(peopleWindow.getContent().get(0))).isEqualTo(ScrollPosition.offset(1));
 					return true;
 				}).verifyComplete();
 	}