java - Spring Data Mongodb - repository for collection with different types -

i have mongo collection may contain 3 types of entities map java types:

• node
• leaftype1
• leaftype2

collection ment store tree-like structure using dbrefs of child nodes in parent entry.

i didn't find information subject in spring reference documentation i'm asking here: there way use repository mechanism work collection may contain different types of objects?

declaring several repositories different types in 1 collection seems not idea because struggle situations when queried object not of expected type , creating 1 repository abstract class possible types inherrit doesn't seems work.

to illustrate mean:

/**  * seems not safe  */ public interface noderepository extends mongorepository<node, string> { } public interface leaftype1repository extends mongorepository<leaftype1, string> { } public interface leaftype2repository extends mongorepository<leaftype2, string> { }  /**  * doesn't work @  */ public interface mycollectionrepository extends mongorepository<abstractmycollectionnode, string> { } 

if node\leaftype1\leaftype2 sub-classes of abstractmycollectionnode, things easy. declare repository write:

public interface mycollectionrepository extends mongorepository<abstractmycollectionnode, string> { } 

we have done in project, , works good. spring data add property named '_class' documents in mongodb collection, can finger out class instantiate.

documents stored in 1 collection may have similarity, maybe can extract generic class them.

here code copied 1 of our projects:

entity:

public abstract class document {     private string id;      public string getid() {         return id;     }      public void setid(string id) {         this.id = id;     }     .... 

---

public class webclipdocument extends document {     private string digest;     ... 

repository:

public interface documentdao extends mongorepository<document, string>{ ... 

and, if documents in mongodb collection not have "_class" property. can use converter:

when storing , querying objects convenient have mongoconverter instance handle mapping of java types dbobjects. however, may want `mongoconverter’s of work allow selectively handle conversion particular type or optimize performance.