没有完整架构的mongodb ORM？

Question

I'm frequently finding myself with one foot in POJO land, and one foot in JSON land. I want my Mongo documents that have a formal, but partially specified schema. POJO land assumes a fully specified schema. JSON land provides no contraints.

As an example, suppose I download a bunch of user data from facebook, it arrives as a JSON blob. Facebook essentially owns this structure and its madness to try to map it into an internal POJO structure - if one days FB changes this, our server break and we stop collecting this data, what the right thing to do is to store it verbatim.

What I want is to specify rules and contraints about what goes into all my databases to the extent possible and the schema is well defined :

• this attribute should be a long
• this attribute needs to be encrypted
• this attribute is optional
• this object can have an number of additional extra fields ...

I'm half way through building such a thing. But though it would be a good idea to see if existing project exist that allow document constraints to be specified.

Answer 1

What you are searching for is called a object-document-mapper or ODM (the document-database analogue to an ORM, or object-relational mapper in SQL databases).

There are different wrappers like this available for Java, like Morphia or Spring-MongoDB . A longer list can be found on Java Language Center on mongodb.org .