Monjo is a lightweight type-safe library for mapping Java objects to/from MongoDB:
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Easy to use, and very lightweight
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Type-safe Query support
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Annotations describe mapping behavior; there are no XML files.
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Extensions: Validation (jsr330), and SLF4J Logging
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Standard Mapping: use a set of rules for determining the physical fields and collections names given the information in the mapping document (ex: naming strategy prefers embedded underscores to mixed case names)
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Javabeans: accessors and mutators are always used to infer fields
@Entity("professionals") class Employee implements IdentificableDocument<ObjectId>{ ObjectId id; // auto-generated, if not set (see ObjectId) String firstName, lastName; // value types are automatically persisted Long salary = null; // only non-null values are stored Address address; // by default fields are embedded @ReferenceKey<Employee> manager; //references can be saved without automatic loading List<Employee> underlings = new ArrayList<Employee>(); // by default, use DBList to persist inner collections @Indexed boolean active = false; //fields can be indexed for better performance @Transient int notStored; //fields can be ignored (no load/save) transient boolean stored = true; //not @Transient, will be ignored by Serialization/GWT for example. }
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Find By Example (find a object using any field, maybe an inner inner inner ... object )
PojoWithListInnerObject pojo = PojoBuilder.createMegaZordePojo(); Monjo<ObjectId, PojoWithListInnerObject> monjo = new Monjo<ObjectId, PojoWithListInnerObject>(getMongoDB(), PojoWithListInnerObject.class); monjo.removeAll(); monjo.insert(createMegaZordePojo); pojo.setId(null); List<Category> categories = pojo.getCategories(); Category category = categories.get(0); category.setName(null); PojoWithListInnerObject result = pojongo.findByExample(pojo.toList().get(0);
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Cursor (select page of selection, sort and so on)
List<SimplePOJO> list = monjo.find().limit(5).toList();
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Update inner Objects
monjo.<Category> updateInnerObject("categories", category, pojo);
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Does not store Null/Empty values (by default).
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GWT support (entities are just POJOs) -- (GWT ignores annotations)
Note: @Reference will not save objects, just a reference to them; You must save them yourself.
This library is currently at a very early development stage, but already being used in production in some really big applications.