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An introduction into Spring Data

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Slides of my talk at OOP2012.

Published in: Technology, Education
  • Hi Oliver Gierke. Can You help me to create generic MongoRepository for all documents. Now we are using one Repository for one document class. we need only one Repository for all classes.
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An introduction into Spring Data

  1. 1. Data Access 2.0? …please welcome… Spring Data! Oliver Gierke
  2. 2. Oliver GierkeSpring DataCore/JPA/MongoDBogierke@vmware.comwww.olivergierke.deolivergierke
  3. 3. What to expect?
  4. 4. How?Why? What?
  5. 5. A Developer‘s View
  6. 6. What to expect? NOT!
  7. 7. What to expect? NOT!
  8. 8. Overview
  9. 9. Relational databases
  10. 10. Scaling
  11. 11. Data structures
  12. 12. Hibari Voldemort Membase Riak Cassandra RedisSimpleDB (No)SQL MongoDB OrientDB CouchDB HBase Sones Neo4J
  13. 13. Key Value
  14. 14. Column families
  15. 15. Graphs
  16. 16. Documents
  17. 17. Document database JSON documents JSON queries
  18. 18. MongoDB Infrastructure API Mongo mongo = new Mongo(…); DB db = mongo.getDB("myDatabase"); Collection collection = db.getCollection("myCollection"); DBObject address = new BasicDBObject(); address.put("city", "London"); DBObject person = new BasicDBObject(); person.put("firstname", "Dave"); person.put("lastname", "Matthews"); person.put("address", address); collection.save(person);19
  19. 19. MongoDB Query API Mongo mongo = new Mongo(…); DB db = mongo.getDB("myDatabase"); Collection collection = db.getCollection("myCollection"); DBObject query = new BasicDBObject(); query.put("address.city", "London"); DBCursor cursor = collection.find(query); for (DBObject element : cursor) { // Map data onto object }20
  20. 20. Graph database Nodes / RelationshipsTraversals / Cypher / Gremlin
  21. 21. Neo4J Infrastructure API GraphDatabaseService database = new EmbeddedGraphDatabase(…); Transaction tx = database.beginTx(); try { Node mrAnderson = database.createNode(); mrAnderson.setProperty("name", "Thomas Anderson"); Node morpheus = database.createNode(); morpheus.setProperty("name", "Morpheus"); Relationship friendship = mrAnderson.createRelationshipTo( morpheus, FriendTypes.KNOWS); tx.success(); } finally { tx.finish(); }22
  22. 22. Neo4J Query API GraphDatabaseService database = new EmbeddedGraphDatabase(…); CypherParser parser = new CypherParser(); Query query = parser.parse("start person = Person(id = *) match " + "person-[:colleagues]->colleague where colleague.firstname = {name}"); Map<String, Object> parameters = new HashMap<String, Object>(); parameters.put("name", "Dave"); ExecutionEngine engine = new ExecutionEngine(database); ExecutionResult result = engine.execute(query, parameters); for (EntrySet<String, Object> element : result) { // Map data onto object }23
  23. 23. Neo4J entity class Actor { private final Node node; public Actor(Node node) { … } public String getName() { return (String) node.getProperty(„name“); } … }24
  24. 24. Forest for the woods?
  25. 25. There‘s someSpring for that!
  26. 26. Spring Data
  27. 27. " … provide a familiar and consistent Spring-based programming model while retaining store-specific features and capabilities.
  28. 28. Spring Data JDBC JPA
  29. 29. Spring Data JDBC JPA
  30. 30. Spring Data JDBC JPA
  31. 31. Spring Data JDBC JPA
  32. 32. Building blocks
  33. 33. Spring
  34. 34. Mapping
  35. 35. JPA entity mapping @Entity class Person { @Id @GeneratedValue(strategy=GenerationType.AUTO) private BigInteger id; private String firstname, lastname; @Column(name="email") private String emailAddress; @OneToMany private Set<Person> colleagues; }36
  36. 36. Entity mapping - MongoDB @Document class Person { @Id private BigInteger id; @Indexed private String firstname, lastname; @Field("email") private String emailAddress; @DBRef private Set<Person> colleagues; public Person(String firstname) { … } @PersistenceConstructor public Person(String firstname, String lastname) { … } … }37
  37. 37. Entity mapping - Neo4J @NodeEntity class Person { @GraphId private long id; @Indexed private String firstname, lastname; @RelatedTo(direction = Direction.INCOMING) private Set<Person> colleagues; public Person(String firstname) { … } @PersistenceConstructor public Person(String firstname, String lastname) { … } … }38
  38. 38. Templates
  39. 39. MongoOperations / -Template public interface MongoOperations { // Generic callback-accepting methods <T> T execute(DbCallback<T> action); <T> T execute(Class<?> entityClass, CollectionCallback<T> action); <T> T execute(String collectionName, CollectionCallback<T> action); // Higher level access methods <T> List<T> find(Query query, Class<T> entityClass); void save(Object objectToSave, String collectionName); WriteResult updateFirst(Query query, Update update, Class<?> entityClass); // Geo API <T> GeoResults<T> geoNear(NearQuery near, Class<T> entityClass); }40
  40. 40. MongoTemplate usage // Setup infrastructure Mongo mongo = new Mongo(); MongoDbFactory factory = new SimpleMongoDbFactory(mongo, „foo“); MongoTemplate template = new MongoTemplate(factory); // Create and save entity Person dave = new Person("Dave", "Matthews"); dave.setEmailAddress("dave@dmband.com"); template.save(person); // Query entity Query query = new Query(new Criteria("emailAddress") .is("dave@dmband.com")); assertThat(template.find(query), is(dave));41
  41. 41. Repositories
  42. 42. Repositories - JPA <jpa:repositories base-package="com.acme.repositories" /> public interface PersonRepository extends Repository<Person, BigInteger> { // Finder for a single entity Person findByEmailAddress(String emailAddress); // Finder for multiple entities List<Person> findByLastnameLike(String lastname); // Finder with pagination Page<Person> findByFirstnameLike(String firstname, Pageable page); }43
  43. 43. Repositories - MongoDB public interface PersonRepository extends Repository<Person, BigInteger> { // Finder for a single entity Person findByEmailAddress(String emailAddress); // Finder for multiple entities List<Person> findByLastnameLike(String lastname); // Finder with pagination Page<Person> findByFirstnameLike(String firstname, Pageable page); // Geospatial queries List<Person> findByLocationNear(Point location, Distance distance); GeoResults<Person> findByLocationNear(Point location); }44
  44. 44. Repositories - MongoDB <mongo:repositories base-package="com.acme.repositories" /> @Component public class MyClient { @Autowired private PersonRepository repository; public List<Person> doSomething() { Point point = new Point(43.7, 48.8); Distance distance = new Distance(200, Metrics.KILOMETERS); return repository.findByLocationNear(point, distance); } }45
  45. 45. Repositories - Neo4J interface PersonRepository extends GraphRepository<Person, Long> // Finder for a single entity Person findByEmailAddress(String emailAddress); // Finder for multiple entities List<Person> findByLastnameLike(String lastname); // Finder with pagination Page<Person> findByFirstnameLike(String firstname, Pageable page); @Query("start person = Person(id = *) " + "match person-[:colleagues]->colleague where " + "colleague.firstname = {name}") List<Person> getPersonsWithColleaguesName( @Param("name") Movie m); }46
  46. 46. Repositories Querydsl47
  47. 47. Querydsl QPerson $ = QPerson.person; BooleanExpression left = $.lastname.contains("eth"); BooleanExpression right = $.firstname.is("Carter"); public interface QueryDslPredicateExecutor<T> { T findOne(Predicate predicate); List<T> findAll(Predicate predicate); } public interface PersonRepository extends Repository<Person, BigInteger>, QueryDslPredicateExecutor { … } List<Person> result = repository.findAll(left.or(right)); assertThat(result.size(), is(2)); assertThat(result, hasItems(dave, carter));48
  48. 48. Wrap up
  49. 49. Wrap upSophisticated mapping support Templates Repositories Querydsl Spring namespaceGeospatial support (MongoDB) Cross-store persistence
  50. 50. Questions?
  51. 51. Resources• www.springframework.org/spring-data• github.com/SpringSource/spring-data-mongodb• github.com/SpringSource/spring-data-neo4j• http://www.se-radio.net/2010/07/episode-165-nosql-and- mongodb-with-dwight-merriman• http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis

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