Enum conversion to String not working on #Indexed unique field - spring-data-neo4j

Question

I'm a Neo4j/Spring-data newbie so apologies if this is something obvious but I looked here and there and can't quite figure out if it's a bug or feature.
I'm using SDN 3.1.0 and Neo4j 2.0.4, running in memory for now (for testing).
I have a super simple POJO that I try to save into Neo4j using SDN. It looks like so:
#NodeEntity
public class Weekday {
#GraphId
private Long id;
#Indexed(unique = true)
public DayOfWeek weekdayCode;
}
Everything works beautifully when I make it non-uniquely indexed, or not indexed at all. It works fine with unique constraint when I make it a String as well. (Well, sort of, I'm aware that it doesn't throw an exception but silently updates existing one - this is not perfect but I found JIRA issue related to that). Unfortunately the moment I try to save it as enum with unique constraint I get an exception:
org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props} return n; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props} return n; nested exception is java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.query(CypherQueryEngineImpl.java:61)
at org.springframework.data.neo4j.support.schema.SchemaIndexProvider.merge(SchemaIndexProvider.java:114)
at [...]
Caused by: org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props} return n; nested exception is java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.parseAndExecuteQuery(CypherQueryEngineImpl.java:72)
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.query(CypherQueryEngineImpl.java:58)
... 63 more
Caused by: java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.neo4j.kernel.api.properties.PropertyConversion.convertProperty(PropertyConversion.java:107)
at org.neo4j.kernel.api.properties.Property.property(Property.java:51)
at [...]
This, as far as I can see, is because the unique field is put into a map "props", and the contents of the map is not automatically converted so it sends an enum to Neo4j, which obviously it doesn't like.
Is this expected or should I raise a bug with SDN?
If that's expected behaviour, do I have any alternatives other than making the field a String?

Answer 1

I'm not sure if it is a real bug, however I had a similar problem using my own Enum class.
So, you could try something like this:
Create the converters
Register them in neo4j
First create your converters like:
#Component
public class StringToDayOfWeekConverter implements Converter<String, DayOfWeek> {
#Override
public DayOfWeek convert(String source) {
return DayOfWeek.valueOf(source);
}
}
#Component
public class DayOfWeekToStringConverter implements Converter<DayOfWeek, String> {
#Override
public String convert(DayOfWeek source) {
return source.name();
}
}
Then you register the converters, so neo4j can use them:
#Configuration
#EnableNeo4jRepositories("my.repository.package")
#EnableTransactionManagement
public class MyNeo4jConfiguration extends Neo4jConfiguration {
#Autowired
private StringToDayOfWeekConverter stringToDayOfWeekConverter;
#Autowired
private DayOfWeekToStringConverter dayOfWeekToStringConverter;
#Override
protected ConversionService neo4jConversionService() throws Exception {
ConverterRegistry converterRegistry = (ConverterRegistry) super.neo4jConversionService();
converterRegistry.addConverter(stringToDayOfWeekConverter);
converterRegistry.addConverter(dayOfWeekToStringConverter);
return (ConversionService) converterRegistry;
}
}

Answer 2

create an converter extends EnumStringConverter such like this:
package com.noopu.pyramid.domain.model.converter;
import com..pyramid.common.UserType;
import org.neo4j.ogm.typeconversion.EnumStringConverter;
public class UserTypeStringConverter extends EnumStringConverter {
public UserTypeStringConverter ( ) {
super ( UserType.class );
}
}
and used #Converter annotation like under:
package com.noopu.pyramid.domain.model;
import com.noopu.pyramid.common.UserType;
import com.noopu.pyramid.domain.model.converter.UserTypeStringConverter;
import lombok.Data;
import org.neo4j.ogm.annotation.GraphId;
import org.neo4j.ogm.annotation.Index;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.typeconversion.Convert;
import java.io.Serializable;
#NodeEntity
#Data
public class User implements Serializable {
private static final long serialVersionUID = 8979348201709416439L;
#GraphId
private Long graphId;
#Index
protected Long id;
#Index(unique = true)
private Long uid;
#Index(unique = true)
private String phone;
#Index
#Convert(UserTypeStringConverter.class)
private UserType type;
}