danieldingzju / morphia

Morphia

Morphia is a lightweight type-safe library for mapping Java objects to/from MongoDB. Morphia provides a typesafe, and fluent Query API support with (runtime) validation. Morphia uses annotations so there are no XML files to manage or update. Morphia should feel very comfortable for any developer with JPA experience.

##Features

• Lifecycle Method/Event Support
• Works great with Guice, Spring, and other DI frameworks.
• Many extension points (new annotations, converters, mapping behavior, logging, etc.)
• Does not store Null/Empty values (by default).
• GWT support (entities are just POJOs) -- (GWT ignores annotations)
• Advanced mapper which allows raw conversion, void toObject(DBObject) or DBObject fromObject(Object)

Please continue by reading the QuickStart or looking at a list of the annotations. If you have further questions, please reach out to us on our mailing list.

Quick start

Including morphia in your build

Maven

<dependency>
    <groupId>org.mongodb.morphia</groupId>
    <artifactId>morphia</artifactId>
    <version>###</version>
</dependency>

See the dependencies page for more detail.

Sample code

@Entity("employees")
class Employee {
  // auto-generated, if not set (see ObjectId)
  @Id ObjectId id;

  // value types are automatically persisted
  String firstName, lastName;

  // only non-null values are stored
  Long salary = null;

  // by default fields are @Embedded
  Address address;

  //references can be saved without automatic loading
  Key<Employee> manager;

  //refs are stored**, and loaded automatically
  @Reference List<Employee> underlings = new ArrayList<Employee>();

  // stored in one binary field
  @Serialized EncryptedReviews;

  //fields can be renamed
  @Property("started") Date startDate;
  @Property("left") Date endDate;

  //fields can be indexed for better performance
  @Indexed boolean active = false;

  //fields can loaded, but not saved
  @NotSaved string readButNotStored;

  //fields can be ignored (no load/save)
  @Transient int notStored;

  //not @Transient, will be ignored by Serialization/GWT for example.
  transient boolean stored = true;

  //Lifecycle methods -- Pre/PostLoad, Pre/PostPersist...
  @PostLoad void postLoad(DBObject dbObj) { ... }
}

...

Datastore ds = ...; // like new Morphia(new Mongo()).createDatastore("hr")
morphia.map(Employee.class);

ds.save(new Employee("Mister", "GOD", null, 0));

// get an employee without a manager
Employee boss = ds.find(Employee.class).field("manager").equal(null).get();

Key<Employee> scottsKey =
  ds.save(new Employee("Scott", "Hernandez", ds.getKey(boss), 150**1000));

//add Scott as an employee of his manager
UpdateResults<Employee> res =
  ds.update(
    boss,
    ds.createUpdateOperations(Employee.class).add("underlings", scottsKey)
  );

// get Scott's boss; the same as the one above.
Employee scottsBoss =
  ds.find(Employee.class).filter("underlings", scottsKey).get();

for (Employee e : ds.find(Employee.class, "manager", boss))
   print(e);

Note: @Reference will not save objects, just a reference to them; You must save them yourself.