Download pdf - Webinar: MongoDB Persistence with Java and Morphia

MongoDB Persistence with Java and Morphia

Software Engineer, MongoDB

Justin Lee

AgendaIntroduction

Getting Started

Modeling

Querying

Updating

Indexing

Road Map

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

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

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

Getting Started

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>

Adding morphia — Gradle

compile "org.mongodb.morphia:morphia:0.105"

compile "org.mongodb:mongo-java-driver:2.11.3"

!

!

Initializing morphia

Morphia morphia = new Morphia();

Datastore datastore = morphia.createDatastore(

new MongoClient(), “morphia-demo");

morphia.mapPackage("org.mongodb.morphia.demo");

datastore.ensureIndexes();

!

Entity Modeling

Basic Entity

@Entity

public class GithubUser {

private String userName;

private String fullName;

!

private Date memberSince;

}

Basic Entity

@Entity




!


}

(value = “users")

Basic Entity

@Entity




!


}

(value = "users", noClassnameStored = true)

Basic Entity

@Entity




!


}


@Id

Basic Entity

@Entity




!


}


@Id

@Property("since")

Basic Entity — Saving

GithubUser user = new GithubUser("evanchooly");

user.fullName = "Justin Lee";

user.memberSince = sdf.parse("6-15-1987");

datastore.save(user);

Basic Entity — Shell

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

Complex Entities

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

Complex Entities

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

Complex Entities

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

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<>(); }

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"));

Complex Entities — Shell

repl0:PRIMARY> show collections orgs repos system.indexes users


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

Complex Entities — Shellrepl0: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" : { … } }


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") ] }

Queries

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(); !… ?

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" } }

Complex Entities

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

Basic Query — @Property

@Entity(value = "users", noClassnameStored = true)


@Id



@Property("since")


}

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}

Updates

Updating Entities

evanchooly.followers = 12; datastore.save(evanchooly);

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 } }

Versioned Updates

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

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.

Indexes

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; !… }

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" } ]

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; !…

What’s Next

The Road to 1.0

• It’s short

• Aggregation support

• Text Searching

• Improved geo support

• Handful of bug fixes

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/morphia-demo

https://github.com/mongodb/morphia

https://groups.google.com/forum/#!forum/morphia

https://github.com/evanchooly/morphia-demo

Questions?

MongoDB Persistence with Java and Morphia

Software Engineer, MongoDB

Justin Lee