The document summarizes Spring Data Neo4j 4.0, a new version of the Spring Data project that provides integration with the Neo4j graph database. It describes Neo4j and Spring Data briefly, then outlines the key features and architecture of SDN 4.0, including a standalone object-graph mapping layer, variable depth persistence, and integration with Spring and repositories. It demonstrates a sample conference application built with SDN 4.0 and provides information on getting started and support resources.

1. GraphAware
TM
Building High Performance Applications
with Spring Data Neo4j 4
Vince Bickers, GraphAware
graphaware.com
@graph_aware

2. Agenda
● A bit about Neo4j and the Spring Data project
● A brief history of SDN
● SDN 4: Spring Data + Standalone Java OGM
● Conference Demo
o Data model
o Code
o Live demo!
● Roadmap
● Q & A

3. Neo4j is a Graph Database
•Nodes & Edges (Relationships)
•Index-free adjacency means super-fast traversals
•Embedded Client and Remote Server
•Schema-flexible!
•Cypher Query Language

4. When worlds collide…
The impedance mismatch

5. Spring Data
•Most active Spring Project
•Consistent APIs to access both RDBMS and NoSQL stores
•JPA, Neo4j, MongoDB, Redis, CouchBase…
•Convenient abstractions for Spring developers

6. Quick History of SD-Neo4j
● SDN 0.x - Rod and Emil wrote it, started Spring Data efforts
● SDN 1.x - Embedded Neo4j, Object Mapping, Templates
● SDN 2.x - Neo4j Server, SD-Repositories
● SDN 3.x - Neo4j 2.x with Label + Schema Index Support, etc.

7. Now… Spring Data Neo4j 4.0
● New and Shiny!
o Complete rewrite
o Neo4j Server only (for now, at least)
o Sympathetic to typical business use cases
o And … not just for Spring developers!

8. Spring Data Neo4j 4 - Progress
● Development started Sep 2014
● Milestone 1 released end Mar 2015
● RC1 end-May 2015
● GA … mid-June 2015

9. Spring Data + Separate OGM
● Standalone Java OGM
● Spring+
o Template methods
o Transactions
o Repositories
o Queries
o Exception Translation
o Conversion Services

10. Approach
● Constraint: Cypher over HTTP
● Solution: Focus on performance!

11. Core OGM - Features
● "Vampire" Metadata scanning (no reflection!)
● Optional annotations
● Mapping contexts scoped to “conversational” lifetimes:
o Application,
o HTTP session,
o HTTP request, etc.
● "Smart" object-mapping
● Variable-depth persistence

12. Variable-depth persistence
If you're interested in loading this...
...you're often really interested in this

13. Variable-depth persistence
If your domain objects are connected….
…you should be able to save them all at once - from any object.

14. Conference Application
Spring Data Neo4j 4.0
Spring Boot
Angular.js

15. Application architecture
Straightforward Spring Boot application:
● RESTControllers
● … depending on Services
● …... depending on Spring Repositories
● to persist POJO Entity classes

16. Entities and Relationships
Entities (Labels)
● Speaker
● Conference
● Track
● Talk (Session)
● Timeslot
Relationships
● PRESENTS
● REGISTERED_FOR
● IN_TRACK
● HAS_TRACK
● AT_TIMESLOT

17. Conference Graph Model
Speaker
Conference
Track
Session
Timeslot
PRESENTS
REGISTERED_FORHAS_TRACK
IN_TRACKAT_TIME_SLOT

18. Preparing the data - CQL
create (conference:Conference {name : 'GraphConnect 2015'})
create (track1:Track {name : 'Technical Track'})
create (track2:Track {name : 'Business Track'})
create (track3:Track {name : 'Practitioner Track'})
create (track4:Track {name : 'Beginner Track'})
create (conference)<-[:REGISTERED_FOR]-(long:Speaker {name : 'Josh Long'})
create (conference)<-[:REGISTERED_FOR]-(gonzalez:Speaker {name : 'Ignasi Gonzalez'})
create (conference)<-[:REGISTERED_FOR]-(lopez:Speaker {name : 'Ivan Lopez'})
create (conference)<-[:REGISTERED_FOR]-(rodriguez:Speaker {name : 'Anton Rodriguez'})
…etc

19. All the data loaded…

20. Configuration: Spring Boot
@SpringBootApplication
@Import(PersistenceConfig.class)
public class ConferenceApplication {
public static void main(String[] args) {
SpringApplication app = new SpringApplication(ConferenceApplication.class);
app.setShowBanner(false);
app.run(args);
}
}

21. Configuration: Persistence
@Configuration
@EnableNeo4jRepositories(basepackages="app.conference.repository")
@EnableTransactionManagement
public class PersistenceConfig extends Neo4jConfiguration {
@Bean public Neo4jServer neo4jServer() {
return new RemoteServer("http://localhost:7474");
}
@Bean public SessionFactory getSessionFactory() {
return new SessionFactory("app.conference.domain");
}
@Bean @Scope(value="session", proxyMode=ScopedProxyMode.TARGET_CLASS)
public Session getSession() throws Exception {
return super.getSession();
}
}

22. Entities: Abstract Entity
@JsonIdentifyInfo(generator=JSOGGenerator.class)
public abstract class Entity {
@JsonProperty("id")
@GraphId
private Long id;
private String name;
}

23. Entities: Speaker
public class Speaker extends Entity {
@Relationship(type="PRESENTS")
private Set<Talk> talks;
}

24. Entities: Talk
@NodeEntity(label="Session")
public class Talk extends Entity {
@Relationship(type="AT_TIMESLOT")
private Timeslot timeslot;
@Relationship(type="IN_TRACK")
private Track track;
@Relationship(type="PRESENTS", direction=Relationship.INCOMING)
private Set<Speaker> presenters;
}

25. Repositories
interface SpeakerRepository extends GraphRepository<Speaker> {
@Query("MATCH(s:Speaker)-[:PRESENTS]->()
return s, count(*) as hits ORDER BY hits DESC")
Iterable<Map<String,Object>> speakersByNumberOfTalks();
}

26. Services - abstraction
public abstract class GenericCRUDService<T> implements Service<T> {
private static final int DEPTH_LIST = 0;
private static final int DEPTH_ENTITY = 1;
@Override
public Iterable<T> findAll() {
return getRepository().findAll(DEPTH_LIST);
}
@Override
public T find(Long id) {
return getRepository().findOne(id, DEPTH_ENTITY);
}
public abstract GraphRepository<T> getRepository();
}

27. Services - implementation
@Service
public class SpeakerService extends GenericCRUDService<Speaker> {
@Autowired
private SpeakerRepository repository;
@Override
public GraphRepository<Speaker> getRepository() {
return repository;
}
}

28. Controllers - abstraction
@RequestMapping(value = "/api")
public abstract class Controller<T> {
public Iterable<T> list() {
return getService().findAll();
}
public T create (T entity) {
return getService().createOrUpdate(entity);
}
// … more controller methods here
public abstract Service<T> getService();
}

29. Controllers - implementation
// controller methods get an @ResponseBody annotation by default, yay!
@RestController
public class TalkController extends Controller<Talk> {
@Autowired private TalkService service;
@RequestMapping(value="/talks", method = RequestMethod.GET)
public Iterable<Talk> list() {
return service.findAll();
}
}

30. Front end: Angular js
● Very simple CRUD application
● Loosely based on jHipster angular templates
● Each JSON entity (track, speaker, etc) fully supported by 5 files:
o config.js
o servicefactory.js
o controllers.js
o list.html
o detail.html

31. Demo
Conference Application

32. Where next?
Immediately after RC1:
● Project code split
● General release mid-June
● More features planned
o Dynamic Properties
o Support for Embedded Neo4j
o Versioning (MVCC)
o Automatic hooks to pre/post-save lifecycle events
o Binary protocol …etc.

33. Getting started
Neo4j: http://neo4j.com/download
SDN4 Conference Application: https://github.com/neo4j-examples/sdn4-
conference
Spring Data Neo4j (4)
Current Release: http://maven.springframework.org/milestone/org/springframework/
data/spring-data-neo4j/4.0.0.M1
Latest Build: http://repo.spring.io/libs-snapshot/org/springframework/data/spring-data-
neo4j/4.0.0.BUILD-SNAPSHOT
Code: https://github.com/spring-projects/spring-data-neo4j/tree/4.0
Documentation: http://docs.spring.io/spring-data/neo4j/docs/4.0.0.M1

34. GraphAware
TM
Getting help
Luanne Misquitta
Adam George
Vince Bickers
Want to track/raise an issue?
○ https://jira.spring.io/browse/DATAGRAPH
Got questions, or need some advice?
○ Check our blog:
http://graphaware.com/blog/
○ Stack Overflow is your friend
graphaware.com
@graph_aware