Spring Data Neo4j 4 : Failed to convert from type java.util.LinkedHashSet<?> to type org.springframework.data.domain.Page<?> - spring-data-neo4j

Question

Having this Repository method
#Query("MATCH (i:`Interest`) WHERE not(i-[:PARENT]->()) return i")
public Page<Interest> findAllByParentIsNull(Pageable pageRequest);
It cause (it didn't respect the specification):
org.springframework.core.convert.ConversionFailedException: Failed to convert from type java.util.LinkedHashSet<?> to type org.springframework.data.domain.Page<?> for value '[com.nearofme.model.Interest#12a4479, com.nearofme.model.Interest#15bdfb3, com.nearofme.model.Interest#1af6067, com.nearofme.model.Interest#1c17d4d, com.nearofme.model.Interest#df65f4, com.nearofme.model.Interest#3b140d, com.nearofme.model.Interest#1e24566, com.nearofme.model.Interest#da49c9]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type java.util.LinkedHashSet<?> to type org.springframework.data.domain.Page<?>
at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:41)
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:192)
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:176)
at org.springframework.data.repository.core.support.QueryExecutionResultHandler.postProcessInvocationResult(QueryExecutionResultHandler.java:75)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:439)
Debugging the code shows that a conversion is needed at the GraphRepositoryQuery level :
#Override
public final Object execute(Object[] parameters) {
Class<?> returnType = graphQueryMethod.getMethod().getReturnType();
Class<?> concreteType = graphQueryMethod.resolveConcreteReturnType();
Map<String, Object> params = resolveParams(parameters);
// could be converted here
return execute(returnType, concreteType, getQueryString(), params);
}
The current code convert the result at GraphRepositoryImpl with the private method updatePage that should be used in the GraphRepositoryQuery
#Override
public Page<T> findAll(Pageable pageable, int depth) {
Collection<T> data = session.loadAll(clazz, convert(pageable.getSort()), new Pagination(pageable.getPageNumber(), pageable.getPageSize()), depth);
return updatePage(pageable, new ArrayList<T>(data));
}

Answer 1

So my current temporary solution is to update GraphRepositoryQuery with :
#Override
public final Object execute(Object[] parameters) {
Class<?> returnType = graphQueryMethod.getMethod().getReturnType();
Class<?> concreteType = graphQueryMethod.resolveConcreteReturnType();
Map<String, Object> params = resolveParams(parameters);
Object result = execute(returnType, concreteType, getQueryString(), params);
if (params.size()>0){
Object param = params.values().toArray()[0];
if (param instanceof Pageable){
Pageable pageable = (Pageable) param;
result = updatePage(pageable, new ArrayList((Collection) result));
}
}
return result;
}
private Page updatePage(Pageable pageable, List results) {
int pageSize = pageable.getPageSize();
int pageOffset = pageable.getOffset();
int total = pageOffset + results.size() + (results.size() == pageSize ? pageSize : 0);
return new PageImpl(results, pageable, total);
}
No more need to convert inside the GraphRepositoryImpl but it still working