These webinar slides provide a quick tour through graphs, graph databases, neo4j and spring data neo4j. The example app discussed is a twitter-graph.

1. Spring Data Neo4j 2.1
Introduction
Michael Hunger, Neo Technology

2. Me & You ?
๏ Me: Michael Hunger, Neo Technology
• Neo4j Community Team
• Spring Data Neo4j Project Lead
• Neo4j Cloud Hosting
• michael.hunger@neotechnology.com / @mesirii
๏ You:
• Java & Spring !
• Enterprise ?
• NOSQL ?
• Cloud (CF, Heroku) ?

3. About the Webinar
๏ Graphs are EveryWhere
๏ Graph Database
๏ Intro Neo4j
๏ Sample App - Twitter Graph
• Domain Model
• Code
๏ Resources, Books, GraphConnect
๏ Questions answered during webinar and Q & A at the end
๏ All your questions will be answered in a follow up blog post,
don‘t hesitate to ask

4. To become part of todays
Twitter-Graph

5. To become part of todays
Twitter-Graph
please tweet with #neo4j #sdn

6. To become part of todays
Twitter-Graph
please tweet with #neo4j #sdn
•your attendance
•questions
•remarks
•....

7. Graphs are
everywhere
5

8. 7
6

9. Science
7
6

10. Science
Biology
Chemistry
7
6

11. Science
Biology
Chemistry
Proteins
Reactions
Environments
7
6 Genes

12. Science
Biology
Chemistry
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

13. Science
Biology
Work
Friends
Neighbor
Family Chemistry
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

14. Computers
Internet
Science
Biology
Work
Friends
Neighbor
Family Chemistry
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

15. Devices
Users
Software
Networks
Services
Computers
Internet
Science
Biology
Work
Friends
Neighbor
Family Chemistry
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

16. Devices
Users
Software
Networks
Services
Computers
Internet
Business Science
Biology
Work
Friends
Neighbor
Family Chemistry
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

17. Devices
Users
Software
Networks
Services
Computers
Internet
Business Science
ERP Biology
Work Geo
Friends
Retail
Neighbor
Family
Cloud Chemistry
Travel
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

18. Devices
Users
Software
Networks
Services
Computers
Internet
Art
Business Science
ERP Biology
Work Geo
Friends
Retail
Neighbor
Family
Cloud Chemistry
Travel
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

19. Devices Stories
Users
Software Creativity
Visuals
Networks
Services
Computers
Internet
Art
Business Science
ERP Biology
Work Geo
Friends
Retail
Neighbor
Family
Cloud Chemistry
Travel
Proteins
Reactions
Politics Environments
7
6 Genes
Society History

20. A Graph Database
Node Node

21. A Graph Database
Typed relationship
Node Node

22. A Graph Database
Typed relationship
Node Node
key: value key: value

23. Neo4j Intro

24. 9

25. 10

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34. Java Lucene
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35. Introducing
The Twitter-Graph
Domain Model

36. Whiteboard it - abstract
:Tweet
:Tweet

37. Whiteboard it - abstract
:User
PO
ST
ED
:Tweet
:User :Tweet
POSTED

38. Whiteboard it - abstract
:User
PO
ST
ED
TAGGED
:Tag
:Tweet TAGG
ED
:Tag
ED
G
AG
:User :Tweet T
POSTED

39. Whiteboard it - abstract
:User
PO
ST
ED
TAGGED
:Tag
:Tweet TAGG
ED
:Tag
NS
O ED
TI G
MEN AG
:User :Tweet T
POSTED

40. Whiteboard friendly - example
Attending the
#SDN #Neo4j
webinar by
@mesirii
Looking forward
to my #SDN webinar

41. Whiteboard friendly - example
@peterneubauer
PO
ST
ED
Attending the
#SDN #Neo4j
webinar by
@mesirii
Looking forward
@mesirii to my #SDN webinar
POSTED

42. Whiteboard friendly - example
@peterneubauer
PO
ST
ED
TAGGED
#Neo4j
Attending the
#SDN #Neo4j TAGG
webinar by ED
@mesirii #SDN
ED
G
Looking forward TAG
@mesirii to my #SDN webinar
POSTED

43. Whiteboard friendly - example
@peterneubauer
PO
ST
ED
TAGGED
#Neo4j
Attending the
#SDN #Neo4j TAGG
webinar by ED
@mesirii #SDN
NS
O ED
TI G
MEN Looking forward TAG
@mesirii to my #SDN webinar
POSTED

44. Cypher Query Language
๏ Declarative query language
• Describe what you want, not how
• Based on pattern matching
๏ Examples:
START peter=node:User(userName=”peterneubauer”) # index lookup
MATCH peter-[:POSTED]->tweet-[:MENTIONS]->user
WHERE user.country = ”SE” and not peter-[:FOLLOWS]-user
RETURN user
START tag=node:Tag(tag = ”Neo4j”)
MATCH tag<-[:TAGGED]-tweet-[:TAGGED]->co_tag
RETURN co_tag.tag, COUNT(*) as cnt
ORDER cnt DESC LIMIT 10
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45. Spring Data Neo4j 2.1

46. Spring Data
๏ Spring Data: VMWare/SpringSource initiative to give Spring
developers easy access to the emerging world of NOSQL
๏ Build on top of common infrastructure
๏ Spring Data Neo4j is the integration library for Neo4j
๏ http://springsource.org/spring-data
๏ Support for other NOSQL approaches
• Redis
• MongoDB
• Hadoop
• GemFire

47. Spring Data Neo4j
๏ The brain child of Rod Johnson & Emil Eifrém
• Wrote functional initial prototype
• Developed by Neo Technology and SpringSource teams
๏ Uses annotations to define graph entities
๏ Entity state backed by graph database
๏ Two modes of Object Graph Mapping
• simple POJO Graph Mapping
• advanced, seamless AspectJ backed Mapping
๏ SD-Repositories support
๏ Neo4j Server Support

48. Classic Neo4j domain class
public class Tag {
private final Node underlyingNode;
Tag( final Node node ) {
underlyingNode = node;
}
public Node getUnderlyingNode() {
return underlyingNode;
}
public final String getTag() {
return (String) underlyingNode.getProperty( “tag” );
}
public void setTag( final String tag ) {
underlyingNode.setProperty( “tag”, tag );
}
}

49. Spring Data Neo4j domain class
@NodeEntity
public class Tag {
@GraphId private Long id;
private String tag;
}

50. Spring Data Neo4j domain class
@NodeEntity
public class Tag {
@GraphId private Long id;
@Indexed(unique = true)
private String tag;
}

51. Defining entity classes

52. Defining entity classes
• @NodeEntity
• Represents a node in the graph
• Fields saved as properties on node
• References stored as relationships between nodes
• Instantiated using Java ‘new’ keyword, like any POJO
• Also returned by lookup mechanisms
• Type information stored in the graph

53. Defining entity classes

54. Defining entity classes
• @RelationshipEntity
• Represents a relationship in the graph
• Fields saved as properties on relationship
• Special fields for start- and end-nodes
• Only returned by lookup methods

55. Tweet domain class
@NodeEntity
public class Tweet {
@GraphId private Long id;
@Indexed(unique=true) Long tweetId;
String text;
@Fetch User sender; // eager loading
@RelatedTo(type="TAGGED") Collection<Tag> tags;
@RelatedTo(type="MENTIONS") Set<User> mentions;
@RelatedTo(type="SOURCE") Tweet source;
}

56. Compare to Core-API approach
@NodeEntity
class Tweet {
...
public Collecti
on<Tag> getTags
final List<Tag> () {
tags = new Link
for ( Relations edList<Tag>();
hip rel : under
RelTypes.TAGGED lyingNode.getRe
, Direction.OUT lationships(
movies.add( new GOING ) ) {
Tag( rel.getEnd
Old
} Node() ) );
return tags;
}
@RelatedTo(type="TAGGED")
gs; New
private Collection<Tag> ta

57. Interface based Repositories
๏ based on Repository infrastructure in Spring Data Commons
๏ just define the interface and the namespace configuration
๏ provide out-of-the-box support for
• CRUD-Operations
• Index-Lookups
• Traversal-Execution
• Annotated Graph-Queries (Cypher, Gremlin)
• Derived Queries
• Spatial Queries
๏ extensible via custom methods with provided implementations
24

58. Repositories
interface TweetRepository extends GraphRepository<Tweet> {
Tweet findByTweetId(String id);
Collection<Tweet> findByTagsTag(String tag);
}
<neo4j:repositories base-package=“org.neo4j.twitter_graph.repositories„/>
@Controller
public class TwitterController {
@Autowired TweetRepository tweetRepository;
@RequestMapping(value = "/tweet/{id}",...)
public String show(Model model, @PathVariable String id) {
Tweet tweet = tweetRepository.findByTweetId(id);
model.addAttribute("tweet", tweet);
return "/tweet/show";
}}
25

59. Neo4j-Template (I)
๏ well known Spring Template Pattern
๏ Resource / Transaction Management
๏ Convenience Methods
๏ Nodes and Entities handling & conversion
๏ Fluent Query Result Handling
๏ Works also via REST with Neo4j-Server
๏ Exception Translation
26

60. REST-Client-Support
<bean id="restGraphDatabaseService"
class="org.sf.data.neo4j.rest.SpringRestGraphDatabase">
<constructor-arg value="http://localhost:7473/db/data" />
</bean>
<neo4j:config graphDatabaseService="restGraphDatabaseService"/>
๏ drop-in replacement for the embedded GraphDatabase
๏ works transparently with POJO-Entity-Mapping and
Neo4j-Template
27

61. Coding the Twitter-Graph
28

62. Todays Coding Exercise
๏ uses Spring Social (minimally)
๏ Simple Domain: Tweets, Users, Tags
• connected Entities
• Repositories, Service
๏ standalone App with
• embedded Neo4j-Database
• (local Neo4j-Server)
29

63. Spring Data Neo4j Guidebook
“Good Relationships”
“I’m excited about Spring Data Neo4j.... Spring Data Neo4j makes working
with Neo4j amazingly easy, and therefore has the potential to make you
more successful as a developer.”
Rod Johnson, founder of Spring
๏ Spring Data Neo4j comes with a great Guide Book, featuring:
• Forewords by Rod Johnson and Emil Eifrem
• Ancineasts.net narrative tutorial walkthrough for
easy to read,
• A comprehensive reference for all the details
• Check it out: http://bit.ly/sdn-book
• Free e-book and printed 30

64. http://cineasts.net
Check Out: http://spring.neo4j.org/tutorial

65. O‘Reilly Spring Data Book
„Modern Data Access for Enterprise Java“
• upcoming book by the Spring Data project leads
• introduction to Spring Data & SD-repositories
• covers all subprojects
• available in O‘Reilly OFPS and O‘Reilly store (e-book)
• http://bit.ly/sd-ofps
32

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33

67. Continue here
๏ See the Spring Data Neo4j site for more info:
http://spring.neo4j.org
๏ Again, don’t miss our guidebook on Spring Data Neo4j
published by InfoQ also printed
http://bit.ly/sdn-book
๏ All about Neo4j: ๏ local Neo4j meetup groups
http://neo4j.org http://neo4j.meetup.com
๏ Neo4j & SDN videos and webinars:
http://video.neo4j.org
๏ Spring Data Forum at
http://spring.neo4j.org/discussions
๏ Neo4j Google Group
• http://neo4j.org/forums

68. Thank You!
Feel free to reach out with questions on
•Twitter,
•Spring-Forums,
•Neo4j-Google-Group
•Stack-Overflow
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