Defining Query for OrientDB - using JSON data - orientdb

Question

I have a question concerning using orientDB for JSON data. In my scenario,
I receive entities which are serialized into JSON. This JSON data should
be stored in orientDB. The relevant code part to create documents
in orientDB looks as follows:
//JSON string created by using Jackson
String jsonStr = "...";
//here some dummy name "test"
ODocument doc = new ODocument("test");
doc.fromJSON(jsonStr);
doc.save();
In the following, I give an example for classes I'm working with
(I left out constructors, getters and setters and other fields which
are not relevant for the example):
class AbstractEntity {
private String oidString;
}
class A extends AbstractEntity {
private List<B> bs;
}
class B extends AbstractEntity {
private List<C> cs;
}
class C extends AbstractEntity {
private List<D> ds;
}
class D extends AbstractEntity {
private int type;
}
As the classes use type List, Jackson needs to store
additional type information in the JSON representation, to be able
to deserialize the data properly.
{
"oidString" : "AAA_oid1",
"bs" : [ "java.util.ArrayList", [ {
"oidString" : "b_oid1",
"cs" : null
}, {
"oidString" : "b_oid2",
"cs" : [ "java.util.ArrayList", [ {
"oidString" : "c_oid1",
"ds" : [ "java.util.ArrayList", [ ] ]
}, {
"oidString" : "c_oid2",
"ds" : [ "java.util.ArrayList", [ {
"oidString" : "d_oid1",
"type" : 2
} ] ]
} ] ]
} ] ]
}
However, I have problems querying such a document if I try to e.g. find all D instances that contain a certain type. I tried to simplify my query by first listing all D instances that can be found for a specific A:
OQuery<?> query = new OSQLSynchQuery<ODocument>(
"select bs.cs.ds from test where oidString = 'AAA_oid1'"
);
This returns: {"#type":"d","#rid":"#-2:0","#version":0,"bs":[null,null]}
The additional type information ("java.util.ArrayList") seems to cause problems for orientDB. If I rewrite my example and only use ArrayList directly, hence, the additional type information is omitted, the query above shows something as a result.
Is there a general solution to this problem? I have to work with JSON data and that JSON data will contain additional type information (it has to).
Can't deal orientDB with this situation?