MongoDB is the leading noSQL database and as with any new technology, some of the biggest questions are about tools and integration. This webinar will cover how to use MongoDB from a Java application and introduce Morphia, the object document mapping library. It will cover the essential features of the framework with examples before moving on to some of the more advanced and upcoming features such as text search and aggregation framework support.

1. MongoDB Persistence
with Java and Morphia
Justin Lee
Software Engineer, MongoDB

2. Agenda
Introduction
Getting Started
Modeling
Querying
Updating
Indexing
Road Map

3. What is Morphia?
•
Object document mapper — https://github.com/mongodb/morphia
•
Provides mapping to/from Java objects to mongodb
•
Annotation-based
•
Embedded objects/documents
•
References (lazy or eager)
•
Fluent query/update APIs
•
Runtime validation

4. Why Morphia?
•
Offload object marshaling
•
automatically keeps up as objects evolve: new, removed, renamed
•
Higher abstraction
•
Simplified management of indexes
•
Unify code with schema management
•
Object/Document Versioning

5. A Brief History
•
Created by Scott Hernandez
•
Hired by 10Gen —> started working on the kernel
•
Morphia left alone for a couple of years
•
Lots of uncertainty
•
James Green forked morphia
•
I was hired in June, 2013 in part to pick up Morphia
•
5 releases since with another pending

6. Getting Started

7. Adding morphia — Maven
<dependency>
<groupId>org.mongodb.morphia</groupId>
<artifactId>morphia</artifactId>
<version>0.105</version>
</dependency>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>2.11.3</version>
</dependency>

8. Adding morphia — Gradle
compile "org.mongodb.morphia:morphia:0.105"
compile "org.mongodb:mongo-java-driver:2.11.3"
!
!

9. Initializing morphia
Morphia morphia = new Morphia();
Datastore datastore = morphia.createDatastore(
new MongoClient(), “morphia-demo");
morphia.mapPackage("org.mongodb.morphia.demo");
datastore.ensureIndexes();
!

10. Entity Modeling

11. Basic Entity
@Entity
public class GithubUser {
private String userName;
private String fullName;
!
private Date memberSince;
}

12. Basic Entity
@Entity (value = “users")
public class GithubUser {
private String userName;
private String fullName;
!
private Date memberSince;
}

13. Basic Entity
@Entity (value = "users", noClassnameStored = true)
public class GithubUser {
private String userName;
private String fullName;
!
private Date memberSince;
}

14. Basic Entity
@Entity (value = "users", noClassnameStored = true)
public class GithubUser {
@Id
private String userName;
private String fullName;
!
private Date memberSince;
}

15. Basic Entity
@Entity (value = "users", noClassnameStored = true)
public class GithubUser {
@Id
private String userName;
private String fullName;
!
}
@Property("since")
private Date memberSince;

16. Basic Entity — Saving
GithubUser user = new GithubUser("evanchooly");
user.fullName = "Justin Lee";
user.memberSince = sdf.parse("6-15-1987");
datastore.save(user);

17. Basic Entity — Shell
repl0:PRIMARY> db.users.findOne()
{
"_id" : "evanchooly",
"fullName" : "Justin Lee",
"since" : ISODate("1987-06-15T04:00:00Z")
}

18. Complex Entities
@Entity("orgs")
public class Organization {
@Id
public String name;
!
}
public Organization(final String name) {
this.name = name;
}

19. Complex Entities
@Embedded
public class Settings {
public String defaultBranch = "master";
public Boolean allowWiki = false;
public Boolean allowIssues = true;
}

20. Complex Entities
@Entity("repos")
public class Repository {
@Id
public String name;
@Reference
public Organization organization;
@Reference
public GithubUser owner;
public Settings settings = new Settings();
}

21. Complex Entities
@Entity(value = "users", noClassnameStored = true)
public class GithubUser {
@Id
public final String userName;
public String fullName;
@Property("since")
public Date memberSince;
@Reference(lazy = true)
public List<Repository> repositories = new
ArrayList<>();
}

22. Complex Entities
Organization org = new Organization("mongodb");
!
GithubUser user = new GithubUser("evanchooly");
user.fullName = "Justin Lee";
user.memberSince = sdf.parse("6-15-1987");
!
datastore.save(org);
datastore.save(user);
!
datastore.save(new Repository(org, "morphia"));
datastore.save(new Repository(user, "morphia"));

23. Complex Entities — Shell
repl0:PRIMARY> show collections
orgs
repos
system.indexes
users

24. Complex Entities — Shell
repl0:PRIMARY> db.orgs.findOne();
{ "_id" : "mongodb", "className" :
"org.mongodb.morphia.demo.Organization" }

25. Complex Entities — Shell
repl0:PRIMARY> db.repos.find().pretty();
{
"_id" : "mongodb/morphia",
"className" : "org.mongodb.morphia.demo.Repository",
"organization" : DBRef("orgs", "mongodb"),
"settings" : {
"defaultBranch" : "master",
"allowWiki" : false,
"allowIssues" : true
}
}
{
"_id" : "evanchooly/morphia",
"className" : "org.mongodb.morphia.demo.Repository",
"owner" : DBRef("users", "evanchooly"),
"settings" : {
…
}
}

26. Complex Entities — Shell
repl0:PRIMARY> db.users.findOne();
{
"_id" : "evanchooly",
"fullName" : "Justin Lee",
"since" : ISODate("1987-06-15T04:00:00Z"),
"repositories" : [
DBRef("repos", "mongodb/morphia"),
DBRef("repos", "evanchooly/morphia")
]
}

27. Queries

28. Basic Query
Query<Repository> query =
datastore.createQuery(Repository.class);
Repository repository = query.get();
!
runQuery called morphia-demo.repos {}
!
List<Repository> repositories = query.asList();
!
runQuery called morphia-demo.repos {}
!
Iterable<Repository> fetch = query.fetch();
!
… ?

29. Basic Query
Query<Repository> query =
datastore.createQuery(Repository.class);
query.field("owner").equal(evanchooly).get();
!
runQuery called morphia-demo.repos { owner: { $ref:
"users", $id: "evanchooly" } }

30. Complex Entities
@Entity("repos")
public class Repository {
@Id
public String name;
@Reference
public Organization organization;
@Reference
public GithubUser owner;
public Settings settings = new Settings();
}

31. Basic Query — @Property
@Entity(value = "users", noClassnameStored = true)
public class GithubUser {
@Id
private String userName;
private String fullName;
@Property("since")
private Date memberSince;
}

32. Basic Query — @Property
datastore.createQuery(GithubUser.class)
.field("memberSince").equal(date).get();
!
GithubUser{userName='evanchooly', fullName='Justin
Lee', memberSince=Mon Jun 15 00:00:00 EDT 1987}
!
datastore.createQuery(GithubUser.class)
.field("since").equal(date).get();
!
GithubUser{userName='evanchooly', fullName='Justin
Lee', memberSince=Mon Jun 15 00:00:00 EDT 1987}

33. Updates

34. Updating Entities
evanchooly.followers = 12;
datastore.save(evanchooly);

35. Multiple Updates
UpdateOperations<GithubUser> update =
datastore.createUpdateOperations(
GithubUser.class)
.inc("followers").set("following", 42);
Query<GithubUser> query =
datastore.createQuery(GithubUser.class)
.field(“followers”)
.equal(0);
datastore.update(query, update);
!
update morphia-demo.users query: { followers: 0 }
update: { $set: { following: 42 }, $inc:
{ followers: 1 } }

36. Versioned Updates
@Entity("orgs")
public class Organization {
@Id
public String name;
@Indexed
public Date created;
@Version(“v”)
private long version;
!
…
!
}

37. Versioned Updates
Organization organization =
datastore.createQuery(Organization.class).get();
Organization organization2 =
datastore.createQuery(Organization.class).get();
!
datastore.save(organization); // fine
datastore.save(organization); // fine
datastore.save(organization2);
!
java.util.ConcurrentModificationException: Entity
of class org.mongodb.morphia.demo.Organization
(id='mongodb',version='1') was concurrently
updated.

38. Indexes

39. Indexes — Fields
@Entity("orgs")
public class Organization {
@Id
public String name;
@Indexed(value = IndexDirection.ASC, unique = false,
name = "", dropDups = false, background = false,
sparse = false, expireAfterSeconds = -1)
public Date created;
!
…
}

40. Indexes — Fields
repl0:PRIMARY> db.orgs.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "morphia-demo.orgs"
},
{
"v" : 1,
"key" : {
"created" : 1
},
"name" : "created_1",
"ns" : "morphia-demo.orgs"
}
]

41. Indexes — Classes
@Entity(value = "users", noClassnameStored = true)
@Indexes({
@Index(value ="userName, -followers", name = "popular")
})
public class GithubUser {
@Id
public String userName;
public String fullName;
@Property("since")
public Date memberSince;
public Date lastActive;
@Reference(lazy = true)
public List<Repository> repositories = new ArrayList<>();
public int followers = 0;
public int following = 0;
!
…

42. What’s Next

43. The Road to 1.0
•
It’s short
•
Aggregation support
•
Text Searching
•
Improved geo support
•
Handful of bug fixes

44. Resources
•
Morphia Homepage https://github.com/mongodb/morphia
•
Discussions Forum https://groups.google.com/forum/#!forum/
morphia
•
This presentation and code https://github.com/evanchooly/morphiademo

45. Questions?

46. MongoDB Persistence
with Java and Morphia
Justin Lee
Software Engineer, MongoDB