3/15 - Intro to Spring Data Neo4j
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WebinarIntroduction to
Spring Data Neo4j 2.0
Michael Hunger, Neo Technology
Thursday, March 15, 12
Me & You ?
๏Me: Michael Hunger, Neo Technology
• passionate software developer / Neo4j German Division
• Spring Data Neo4j Project Lead
•Neo4j Cloud Hosting
•michael.hunger@neotechnology.com / @mesirii
๏You:
• Java & Spring !
• Enterprise ?
• Rich Domain ?
•NOSQL ?
Thursday, March 15, 12
About the Webinar
๏Covers Spring Data Neo4j only
๏too much content anyway
๏so it will be just a whirlwind tour
๏no detailed introductions to NOSQL and Neo4j in particular
๏ for those go to http://neo4j.org
๏Q&A at the end
๏all your questions will be answered in a follow up blog post, don‘t hesitate to ask
Thursday, March 15, 12
What‘s up?
๏Spring Data overview
๏Networks are everywhere
๏Neo4j introduction
๏Spring Data Neo4j introduction
4
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Spring Data
5
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What is NOSQL?
Thursday, March 15, 12
What is NOSQL?
It’s not “No to SQL”
Thursday, March 15, 12
What is NOSQL?
It’s not “No to SQL”
It’s not “Never SQL”
Thursday, March 15, 12
What is NOSQL?
It’s not “No to SQL”
It’s not “Never SQL”
It’s “Not Only SQL”
Thursday, March 15, 12
What is NOSQL?
It’s not “No to SQL”
It’s not “Never SQL”
It’s “Not Only SQL”
NOSQL \no-seek-wool\ n. Describes ongoing trend where developers increasingly opt for non-relational databases to help solve their problems, in an effort to use the right tool for the right job.
Thursday, March 15, 12
NOSQL categories
We see four main categories in the NOSQL space:
Thursday, March 15, 12
NOSQL categories
We see four main categories in the NOSQL space:
•Redis
•Riak
•Voldemort
Key-Value
Thursday, March 15, 12
NOSQL categories
We see four main categories in the NOSQL space:
•Cassandra
•HBase
Column-family/BigTable
•Redis
•Riak
•Voldemort
Key-Value
Thursday, March 15, 12
NOSQL categories
We see four main categories in the NOSQL space:
•Cassandra
•HBase
Column-family/BigTable
•Redis
•Riak
•Voldemort
Key-Value
•MongoDB
•CouchDB
Document
Thursday, March 15, 12
NOSQL categories
We see four main categories in the NOSQL space:
•Cassandra
•HBase
Column-family/BigTable
•Redis
•Riak
•Voldemort
Key-Value
•MongoDB
•CouchDB
Document
•Neo4j
•InfiniteGraph
•OrientDB
•DEX
Graph
Thursday, March 15, 12
Scaling to size vs. Scaling to complexity
8
Size
Complexity
Key-Value stores
Bigtable clones
Document databases
Graph databases
Thursday, March 15, 12
Scaling to size vs. Scaling to complexity
8
Size
Complexity
Key-Value stores
Bigtable clones
Document databases
Graph databases
Billions of nodesand relationships
Thursday, March 15, 12
Scaling to size vs. Scaling to complexity
8
Size
Complexity
Key-Value stores
Bigtable clones
Document databases
Graph databases
> 90% of use cases
Billions of nodesand relationships
Thursday, March 15, 12
Why NOSQL now?
๏Trend 1: Size of data is growing
๏Trend 2: Data is increasingly connected
๏Trend 3: Data is increasingly semi-structured
๏Trend 4: Change in architecture
We have observed four trends since the 90‘s:
Thursday, March 15, 12
What is Spring Data?
10
๏VMWare/SpringSource initiative to give Spring developers easy access to the emerging world of NOSQL, including:
•Non-relational databases
•Grails NOSQL support
•Cross-store persistence
•Object Persistence Mapping Infrastructure
•Generic Repository Infrastructure
• upcoming Spring Roo add-ons
Thursday, March 15, 12
Spring Data projects
๏Code is in SpringSource git repository:
• http://springsource.org/spring-data
• https://github.com/SpringSource/spring-data-*
๏ Includes:
• data-commons
• spring-data-graph-neo4j
• spring-data-{redis,riak}
• spring-data-mongo
• spring-data-jdbc
• spring-data-jpa
Thursday, March 15, 12
Spring Data Neo4j
๏Focus on Spring Data Neo4j
๏VMWare is collaborating with Neo Technology, the company behind the Neo4j graph database.
๏Improved programming model: Annotation-based programming model for applications with rich domain models
๏Cross-store persistence: Extend existing JPA application with NOSQL persistence
๏Spring Roo support: Add graph persistence with Roo add-on
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13
Graphs are everywhere
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Even in the Matrix- everything is a graph
14
Google Image Search: „graph OR network“
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Graphs Everywhere
๏Relationships in
• Politics, Economics, History, Science, Transportation
๏Biology, Chemistry, Physics, Sociology
•Body, Ecosphere, Reaction, Interactions
๏ Internet / IT
•Hardware, Software, Interaction
๏Social Networks
• Family, Friends
•Work, Communities
•Neighbours, Cities, Society 15
Thursday, March 15, 12
Good Relationships
๏World is rich, messy and related data
๏Relationships are as least as important as the things they connect
๏Graphs = Whole > Sum of all parts
๏Complex interactions
๏Always changing, change of structures as well
๏Graph => Relationships are part of the data
๏RDBMS => Relationships part of the fixed schema
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Questions and Answers
๏Complex Questions
๏Answers lie between the lines (things)
๏Locality of the information
๏Global searches / operations very expensive
๏Constant query time, regardless of data volume
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Categories ?
๏Categories == Classes, Trees ?
๏What if more than one category fits?
๏Tags
๏Categories via relationships like „IS_A“
๏Any number, easy to change
๏„Virtual“ Relationships - Traversals
๏Category dynamically derived from queries
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Neo4j introduction
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What is Neo4j?data model
Thursday, March 15, 12
What is Neo4j?
A Graph Databasedata model
Thursday, March 15, 12
What is Neo4j?
A Graph Databasedata model
Thursday, March 15, 12
What is Neo4j?
A Graph Databasedata model
Thursday, March 15, 12
What is Neo4j?
Node Node
A Graph Databasedata model
Thursday, March 15, 12
What is Neo4j?
Node Node
A Graph Database
Typed relationship
data model
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What is Neo4j?
NodeNode
A Graph Database
Typed relationship
data model
key: value key: value
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For example
Thursday, March 15, 12
For example
name: Oliver
Thursday, March 15, 12
For example
name: Oliver name: Michael
Thursday, March 15, 12
For example
name: Oliver name: MichaelWORKS_WITHproject: spring-data
Thursday, March 15, 12
For example
name: Oliver name: MichaelWORKS_WITHproject: spring-data
company: VMware
EMPLOYED_BY
city: Dresdencountry: DE
LIVE
S_IN
Thursday, March 15, 12
For example
name: Oliver name: MichaelWORKS_WITHproject: spring-data
company: VMware
EMPLOYED_BY
city: Dresdencountry: DE
LIVE
S_IN
name: Rod
KNOWS KNOWS
Thursday, March 15, 12
For example
name: Oliver name: MichaelWORKS_WITHproject: spring-data
company: VMware
EMPLOYED_BY
city: Dresdencountry: DE
LIVE
S_IN
name: Rod
KNOWS KNOWS
food: Chinese
LIKE
S
Thursday, March 15, 12
Facts about Neo4j
•Written in Java •Embeddable or standalone Server•Schema-free - perfect for rich domains•Fully transactional (ACID)•Persistent to custom on-disk file structure•Traversal speeds of 1,000,000+ hops per second•Integrated indexing•Plenthora of language bindings•24/7 production since 2003
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Show me some code, please
Node david = graphDb.createNode();Node andreas = graphDb.createNode();
david.setProperty(“name”, “David Montag”);andreas.setProperty(“name”, “Andreas Kollegger”);
Relationship presentedWith = david.createRelationshipTo( andreas, PresentationTypes.PRESENTED_WITH);presentedWith.setProperty(“date”, System.currentTimeMillis());
GraphDatabaseService graphDb = new EmbeddedGraphDatabase(“var/neo4j”);
Thursday, March 15, 12
Show me some code, please
Node david = graphDb.createNode();Node andreas = graphDb.createNode();
david.setProperty(“name”, “David Montag”);andreas.setProperty(“name”, “Andreas Kollegger”);
Relationship presentedWith = david.createRelationshipTo( andreas, PresentationTypes.PRESENTED_WITH);presentedWith.setProperty(“date”, System.currentTimeMillis());
Transaction tx = graphDb.beginTx();try {
tx.success();} finally { tx.finish();}
GraphDatabaseService graphDb = new EmbeddedGraphDatabase(“var/neo4j”);
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Traversal framework
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Traversal frameworkExample: a dependency graph
A
BDC
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Traversal frameworkExample: a dependency graph
A
BDC
Query: Find all dependencies of A, transitively
Thursday, March 15, 12
Traversal frameworkExample: a dependency graph
A
BDC
Query: Find all dependencies of A, transitively
Thursday, March 15, 12
Traversal frameworkExample: a dependency graph
A
BDC
Query: Find all dependencies of A, transitively
Thursday, March 15, 12
Traversal frameworkExample: a dependency graph
A
BDC
Query: Find all dependencies of A, transitively
Thursday, March 15, 12
Traversal frameworkExample: a dependency graph
A
BDC
Query: Find all dependencies of A, transitively
TraversalDescription desc = Traversal.description() .relationships(ExampleTypes.DEPENDS_ON, Direction.OUTGOING);
Node a = ...;
for (Node dependency : desc.traverse(a).nodes()) { print(dependency);}
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So how do I find a node to traverse from?
?
Thursday, March 15, 12
So how do I find a node to traverse from?
?By us
ing in
dexin
g!
Thursday, March 15, 12
So how do I find a node to traverse from?
?name: DavidBy us
ing in
dexin
g!
Thursday, March 15, 12
So how do I find a node to traverse from?
?Davidname: DavidBy
using
inde
xing!
Thursday, March 15, 12
So how do I find a node to traverse from?
?Davidname: David
Ed
Allison
Michael
Andreas
By us
ing in
dexin
g!
Thursday, March 15, 12
Cypher Query Language
๏Declarative query language
•Describe what you want, not how
•Based on pattern matching
๏Examples:
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START david=node:people(name=”David M”) # index lookupMATCH david-[:knows]-friends-[:knows]-new_friendsWHERE new_friends.age > 18RETURN new_friends
START user=node(5, 15, 26, 28) # node IDsMATCH user--friendRETURN user, COUNT(friend), SUM(friend.money)
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Beyond basics๏Traversal API / DSL
• Express powerful Graph Traversals succinctly
๏Graph algorithm library
•Cheapest path (Dijkstra, A*)
• Shortest path
• Simple paths
•All paths
๏REST API access to Neo4j Standalone Server
๏High availability and online backups
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Spring Data Neo4j 2.0
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Spring Framework Conveniences
๏default enterprise development framework
๏ future Java Cloud stack
๏POJO centric application design
๏made AspectJ aspects socially acceptable (tx-config, @Configurable)
๏Template programming model
๏ Inversion of Control / Dependency Injection
๏Spring Java Config, configuration XML-namespaces
๏ lots of powerful libraries and library abstractions
๏existing, well-known persistence framework for JDBC
๏Spring Data project
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Programming model overview
๏SDN is the brain child of Rod Johnson and 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
• POJO Graph Mapping
• seamless AspectJ backed Object Graph Mapping
๏Spring Roo add-on available
Thursday, March 15, 12
Spring Data Neo4j features
๏ Annotation-based programming model
๏ Spring Data Commons Repository support
๏ Neo4j Query (Cypher, Gremlin) and Traversal support
• on dynamic fields and via repository methods
๏ Neo4j indexing support (includes fulltext and numeric range queries)
๏ Entity types stored in the graph database as well
๏ Dynamic type projection (duck typing)
๏ Cross-store support for partial JPA / graph entities
๏ Support for JSR-303 (bean validation)
๏ Support for the Neo4j Server (remote server and in server extension)
๏ Neo4jTemplate with exception translation, optional transaction management and more
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public class Actor { private final Node underlyingNode;
Actor( final Node node ) { underlyingNode = node; }
public Node getUnderlyingNode() { return underlyingNode; }
public final String getName() { return (String) underlyingNode.getProperty( “name” ); }
public void setName( final String name ) { underlyingNode.setProperty( “name”, name ); }}
Classic Neo4j domain class
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Spring Data Neo4j domain class
@NodeEntitypublic class Actor { @Indexed private String name;}
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What about relationships
public Iterable<Movie> getMovies() { final List<Movie> movies = new LinkedList<Movie>(); for ( Relationship rel : underlyingNode.getRelationships( RelTypes.ACTS_IN, Direction.OUTGOING ) ) { movies.add( new Movie( rel.getEndNode() ) ); } return movies; }
@NodeEntityclass Actor { ...
Old @RelatedTo(type="ACTS_IN", elementCl
ass = Movie.class)
private Set<Movie> movies; public Iterable<Movie> getMovies() {
return movies; }
New
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Defining entity classes
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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
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Defining entity classes
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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
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Fields in node entities (@NodeEntity)
• Primitive types and strings are directly persisted
• For all other types, Spring conversion support can be used
• Enum and Date conversion is provided out-of-the-box
•Transient fields not persisted
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@NodeEntitypublic class Actor { private String name; private int age; private HairColor hairColor; private transient String nickname;}
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Fields in node entities (@NodeEntity)
• Fields of types that represent a node (@NodeEntity)
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Thursday, March 15, 12
Fields in node entities (@NodeEntity)
• Fields of types that represent a node (@NodeEntity)
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@NodeEntitypublic class Movie {}
@NodeEntitypublic class Person { private Movie favoriteMovie;}
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Fields in node entities (@NodeEntity)
• Fields of types that represent a node (@NodeEntity)
38
@NodeEntitypublic class Movie {}
@NodeEntitypublic class Person { private Movie favoriteMovie;}
@NodeEntitypublic class Movie { private Actor topActor;}
@NodeEntitypublic class Actor { // Mirrors topActor in Movie @RelatedTo(type = ”topActor”, direction = Direction.INCOMING) private Movie wasTopActorIn;}
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Fields in node entities (@NodeEntity)
• Fields of collections of node entities: @RelatedTo
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@NodeEntitypublic class Movie {}
@NodeEntitypublic class Actor { @RelatedTo(type = “ACTS_IN”) private Set<Movie> movies;}
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Fields in node entities (@NodeEntity)
๏Fields of collections of relationship entities: @RelatedToVia
๏Read only view of relationship entities40
@RelationshipEntitypublic class Role { @StartNode private Actor actor; @EndNode private Movie movie; private String roleName;}
@NodeEntitypublic class Actor { @RelatedToVia(type = “ACTS_IN”) private Iterable<Role> roles;}
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Fields in relationship entities (@RelationshipEntity)
• Primitive and convertible types work just the same
• @StartNode and @EndNode provide access to the start and end node entities for the relationship entity
@RelationshipEntitypublic class Role { @StartNode private Actor actor; @EndNode private Movie movie; private String title;}
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Indexing
@NodeEntitypublic class Actor { @Indexed private String name; @Indexed private HairColor hairColor;
GraphRepository<Actor> actorRepo = template.repositoryFor(Actor.class);Actor kevin = actorRepo.findByPropertyValue(“name”, “Kevin Bacon”);Iterable<Actor> allBlondActors = actorRepo.findAllByPropertyValue(“hairColor”, “blond”);
It can then be looked up:
By annotating an entity field with @Indexed it becomes searchable:
Thursday, March 15, 12
Indexing
@NodeEntitypublic class Actor { @Indexed(type = FULLTEXT) private String name;
๏ Index name defaults to domain class name
๏ Index key defaults to field name
๏Fulltext and spatial index types
๏Repository query methods for any Lucene query, including ranges:
Iterable<Actor> allKevinsOlderThan32 = actorRepo.findAllByQuery(“name:Kevin* AND age>32”);Iterable<Actor> youngActors = actorRepo.findAllByRange(“age”, 3, 18);
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Traversal
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@NodeEntitypublic class Actor { @GraphTraversal( traversalBuilder = CoactorsTraversalDescriptionBuilder.class) private Iterable<Actor> coactors;}
public class CoactorsTraversalDescriptionBuilder implements FieldTraversalDescriptionBuilder { public TraversalDescription build(...) { return Traversal.description() .evaluator(Evaluators.atDepth(2)) .relationships(RelTypes.ACTS_IN); }}
Example for dynamic field computation
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Cypher query language
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@NodeEntitypublic class Actor { @Query(“START actor=node({self}) ” + “MATCH actor-[:ACTS_IN]->movie<-[:ACTS_IN]-coactor ” + “RETURN coactor”) private Iterable<Actor> coactors;}
@NodeEntitypublic class User { @Query(“START actor=node({self}) ” + “MATCH actor-[:ACTS_IN]->movie<-[:ACTS_IN]-coactor ” + “RETURN movie.title, coactor.name”) private List<Map<String, Object>> movieCoactorPairs;}
Thursday, March 15, 12
POJO-Mapping
46
๏Based on Spring-Data-Commons infrastructure
• Extract Mapping Meta Information
• Entity-Converter for Object-Graph-Mapping
‣Type-resolution
‣Entity construction
‣Transfer properties
‣Load Cache
‣Load Policies + recurse for eagerly fetched relationships
•Neo4j-Template for Graph-Interaction
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AspectJ
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๏ Introduces interface to entities:
•NodeBacked into @NodeEntity classes
• RelationshipBacked into @RelationshipEntity classes
๏NodeBacked introduces methods such as:
• relateTo
• findByQuery
• findAllByTraversal
• ...
๏going to be pulled out in separate Active-Record-Mixin
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AspectJ - Tooling
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๏ IDE‘s
• latest versions of STS / Eclipse with current AJDT plugin
• IntelliJ IDEA 10.5 compile + run, some editor quirks
‣full AspectJ support in IDEA 11
๏Build Systems
•Maven
•Gradle
•Ant / Ivy
• ...
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AspectJ - NodeBacked.relateTo
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<T extends RelationshipBacked> T NodeBacked.relateTo( NodeBacked node, Class<T> relationshipEntityType, String relationshipType);
@NodeEntitypublic class Actor { public Role actsIn(Movie movie, String roleName) { Role role = relateTo(movie, Role.class, “ACTS_IN”); role.setName(roleName); return role; }}
usage:
Thursday, March 15, 12
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 implementations50
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Repositories
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interface MovieRepository extends GraphRepository<Movie> { Movie findById(String id); Page<Movie> findByTitle(String title, Pageable page);}
<neo4j:repositories base-package=“com.example.repositories„/>
@Controllerpublic class MovieController { @Autowired MovieRepository moviesRepository;
@RequestMapping(value = "/movies/{movieId}",...) public String show(Model model, @PathVariable String movieId) { Movie movie = moviesRepository.findByPropertyValue("id", movieId); Movie movie = moviesRepository.findById(movieId); model.addAttribute("movie", movie); return "/movies/show"; }}
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Repository-Query-Support
52
interface MovieRepository extends GraphRepository<Movie> {
@Query("start m=({movie}) match m-[ACTS_IN]-actor return actor") List<Actor> getActorsCypher(@Param("movie") Movie m); @Query("start movie =({0}) match (movie)<-[role:ACTS_IN]-(actor) return actor.name, role.title") Iterable<Map<String,Object>> getCast(Movie m);
@Query(value = "g.v(movie).out('ACTS_IN')", type = QueryType.Gremlin) Set<Person> getActorsGremlin(@Param("movie") Movie m);
Page<Person> findByTitleAndActorsName(String title, String name, Pageable page); }
Thursday, March 15, 12
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
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Neo4j-Template (II)
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template.lookup("node", "name", "David") .to(String.class, new PropertyContainerNameConverter()).single()
template.traverse(node, traversal) .to(Integer.class,new ResultConverter<Path,Integer>() { public Integer convert(Path path, Class<String> type) { return path.length(); }})
template.query("start movie=(Movies,title, {m}) match movie-->actor return actor", map("m","Matrix")).to(Actor.class)
template.execute("g.v(ref).outE", map("ref",0)).to(Relationship.class)
Thursday, March 15, 12
REST-Client-Support
55
<bean id="restGraphDatabaseService" class="org.sf.data.neo4j.rest.SpringRestGraphDatabase"> <constructor-arg value="http://localhost:7473/db/data" /> </bean>
<datagraph:config graphDatabaseService="restGraphDatabaseService"/>
๏drop-in replacement for the embedded GraphDatabase
๏works transparently with POJO-Entity-Mapping and
Neo4j-Template
Thursday, March 15, 12
REST-Server-Support
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public class HelloWorldInitializer extends SpringPluginInitializer { public HelloWorldInitializer() { super(new String[]{"spring/helloWorldServer-Context.xml"}, Pair.of("worldRepository", WorldRepository.class), Pair.of("graphRepositoryFactory", GraphRepositoryFactory.class)); }}
๏ integrate Spring Data Neo4j config with already running
Graph-Database in Neo4j-Server
๏expose Spring Beans as Jersey Injectables
Thursday, March 15, 12
Cross-store persistence
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A scenario...
You have a traditional web app using JPA to persist data to a relational database
Thursday, March 15, 12
Option C: Introducing cross-store persistence
๏ JPA data and NOSQL data can share a data model
๏Could be the entire entity, or some fields of an entity
๏We call this cross-store persistence
•One transaction manager to coordinate the NOSQL database with the JPA relational database
•AspectJ support to manage the NOSQL entities and fields
Thursday, March 15, 12
The JPA data model
Restaurant@Entitypublic class Restaurant {
@Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
Thursday, March 15, 12
Adding to the data model
Recommendation
@RelationshipEntitypublic class Recommendation { @StartNode private UserAccount user; @EndNode private Restaurant restaurant; private int stars; private String comment;
Restaurant@Entity@NodeEntity(partial = true)public class Restaurant { @Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")@NodeEntity(partial = true)public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
@GraphProperty String nickname; @RelatedTo(type = "friends", elementClass = UserAccount.class) Set<UserAccount> friends; @RelatedToVia(type = "recommends", elementClass = Recommendation.class) Iterable<Recommendation> recommendations;
Thursday, March 15, 12
Adding to the data model
Recommendation
@RelationshipEntitypublic class Recommendation { @StartNode private UserAccount user; @EndNode private Restaurant restaurant; private int stars; private String comment;
Restaurant@Entity@NodeEntity(partial = true)public class Restaurant { @Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")@NodeEntity(partial = true)public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
@GraphProperty String nickname; @RelatedTo(type = "friends", elementClass = UserAccount.class) Set<UserAccount> friends; @RelatedToVia(type = "recommends", elementClass = Recommendation.class) Iterable<Recommendation> recommendations;
Thursday, March 15, 12
Adding to the data model
Recommendation
@RelationshipEntitypublic class Recommendation { @StartNode private UserAccount user; @EndNode private Restaurant restaurant; private int stars; private String comment;
Restaurant@Entity@NodeEntity(partial = true)public class Restaurant { @Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")@NodeEntity(partial = true)public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
@GraphProperty String nickname; @RelatedTo(type = "friends", elementClass = UserAccount.class) Set<UserAccount> friends; @RelatedToVia(type = "recommends", elementClass = Recommendation.class) Iterable<Recommendation> recommendations;
Thursday, March 15, 12
Adding to the data model
Recommendation
@RelationshipEntitypublic class Recommendation { @StartNode private UserAccount user; @EndNode private Restaurant restaurant; private int stars; private String comment;
Restaurant@Entity@NodeEntity(partial = true)public class Restaurant { @Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")@NodeEntity(partial = true)public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
@GraphProperty String nickname; @RelatedTo(type = "friends", elementClass = UserAccount.class) Set<UserAccount> friends; @RelatedToVia(type = "recommends", elementClass = Recommendation.class) Iterable<Recommendation> recommendations;
Thursday, March 15, 12
Adding to the data model
Recommendation
@RelationshipEntitypublic class Recommendation { @StartNode private UserAccount user; @EndNode private Restaurant restaurant; private int stars; private String comment;
Restaurant@Entity@NodeEntity(partial = true)public class Restaurant { @Id @GeneratedValue private Long id; private String name; private String city; private String state; private String zipCode;
UserAccount@Entity@Table(name = "user_account")@NodeEntity(partial = true)public class UserAccount { @Id @GeneratedValue private Long id; private String userName; private String firstName; private String lastName; @Temporal(TemporalType.TIMESTAMP) private Date birthDate; @ManyToMany(cascade = CascadeType.ALL) private Set<Restaurant> favorites;
@GraphProperty String nickname; @RelatedTo(type = "friends", elementClass = UserAccount.class) Set<UserAccount> friends; @RelatedToVia(type = "recommends", elementClass = Recommendation.class) Iterable<Recommendation> recommendations;
Thursday, March 15, 12
Spring Data Neo4j Roo add-on
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๏Roo adding support for non-JPA persistence providers
๏Spring Data Neo4j was the first NOSQL persistence Roo Add-On
๏See the chapter on Spring Data Neo4j in the latest O’Reilly Roo book, Getting Started with Roo.
Thursday, March 15, 12
Spring Data Neo4j Roo add-on
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roo> project --topLevelPackage org.neo4j.imdbroo> graph setup --provider NEO4J --databaseLocation target/imdb
roo> graph entity --class ~.model.Movieroo> field string titleroo> field number --fieldName year --type java.lang.Integer --permitReservedWords --primitive
roo> graph entity --class ~.model.Actorroo> field string name
roo> graph relationship --to Movie --from Actor --fieldName movies --type ACTS_IN --cardinality ONE_TO_MANYroo> graph relationship --via ~.model.Role --to Movie --from Actor --fieldName roles --type ACTS_IN --cardinality ONE_TO_MANYroo> graph relationship --from Movie --to Actor --type ACTS_IN --fieldName actors --direction INCOMING --cardinality MANY_TO_ONEroo> field string --fieldName title --class ~.model.Role
roo> controller scaffold --class ~.web.ActorController --entity ~.model.Actorroo> controller scaffold --class ~.web.MovieController --entity ~.model.Movie
Thursday, March 15, 12
Spring Data Neo4j Guidebook“Good Relationships”
๏Spring Data Neo4j comes with a great Guide Book, featuring:
• Forewords by Rod Johnson and Emil Eifrem
•An easy to read, narrative tutorial walkthrough for cineasts.net
•A comprehensive reference for all the details
•Check it out here: http://spring.neo4j.org/guide
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“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
Thursday, March 15, 12
The end (and the beginning!)๏See the Spring Data Neo4j site for more info:
http://spring.neo4j.org
๏Check out the developer notes at GitHub:http://spring.neo4j.org/notes
๏Again, don’t miss our fantastic e-book on Spring Data Neo4j:http://spring.neo4j.org/guide
๏Spring Data Forum at http://spring.neo4j.org/discussions
๏All about Neo4j: http://neo4j.org
๏Neo4j videos and webinars: http://video.neo4j.org
Thursday, March 15, 12
Cineasts.net
Check Out: http://spring.neo4j.org/tutorialThursday, March 15, 12
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