JPA - Create document tree with specific elements from database - sql

Question

I have a web app where you select documents and display them. The document tree is generated from a sql table with a one to many relationship on itself.
What it looks like on the frontend
This tree is generated from an sql table with the following columns :
(page_id, position, title, version, parent_id)
The sql table in question
I can already query this table and retrieve a tree like the following :
{
"position": 0,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"parentId": "2",
"id": "5",
"name": "Page 1"
},
{
"position": 1,
"version": 51,
"parentId": "2",
"id": "6",
"name": "Page 2"
},
{
"position": 2,
"version": 51,
"parentId": "2",
"id": "7",
"name": "Page 3"
}
],
"parentId": "1",
"id": "2",
"name": "Category 1"
},
{
"position": 1,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"parentId": "3",
"id": "8",
"name": "Page 4"
},
{
"position": 1,
"version": 51,
"parentId": "3",
"id": "9",
"name": "Page 5"
},
{
"position": 2,
"version": 51,
"parentId": "3",
"id": "10",
"name": "Page 6"
},
{
"position": 3,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"parentId": "4",
"id": "11",
"name": "Page 7"
},
{
"position": 1,
"version": 51,
"parentId": "4",
"id": "12",
"name": "Page 8"
},
{
"position": 2,
"version": 51,
"parentId": "4",
"id": "13",
"name": "Page 9"
}
],
"parentId": "3",
"id": "4",
"name": "Category 3"
}
],
"parentId": "1",
"id": "3",
"name": "Category 2"
}
],
"parentId": "0",
"id": "1",
"name": "Doc Root"
}
This is the entity class :
#Entity
#Table
#AllArgsConstructor
#NoArgsConstructor
#Getter
#Setter
#JsonInclude(JsonInclude.Include.NON_EMPTY)
public class Node {
#Id
#JsonProperty("id")
private Long pageId;
public String getPageId() {
return pageId.toString();
}
#ManyToOne(cascade = CascadeType.ALL)
#JsonBackReference
#JoinColumn(name = "parent_id")
private Node parent;
public String getParentId() {
return parent.getPageId();
}
private Long position;
private Long version;
#JsonProperty("name")
private String title;
#OneToMany(mappedBy = "parent")
#OrderBy(value = "position asc")
#JsonManagedReference
private List<Node> children;
}
What I am trying to do is to retrieve only parts of this tree depending on the selected nodes. For reference, with the above selections, I'd like to receive a tree with the following content :
{
"position": 0,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"parentId": "2",
"id": "5",
"name": "Page 1"
},
{
"position": 1,
"version": 51,
"parentId": "2",
"id": "6",
"name": "Page 2"
},
{
"position": 2,
"version": 51,
"parentId": "2",
"id": "7",
"name": "Page 3"
}
],
"parentId": "1",
"id": "2",
"name": "Category 1"
},
{
"position": 1,
"version": 51,
"children": [
{
"position": 3,
"version": 51,
"children": [
{
"position": 0,
"version": 51,
"parentId": "4",
"id": "11",
"name": "Page 7"
},
{
"position": 1,
"version": 51,
"parentId": "4",
"id": "12",
"name": "Page 8"
},
{
"position": 2,
"version": 51,
"parentId": "4",
"id": "13",
"name": "Page 9"
}
],
"parentId": "3",
"id": "4",
"name": "Category 3"
}
],
"parentId": "1",
"id": "3",
"name": "Category 2"
}
],
"parentId": "0",
"id": "1",
"name": "Doc Root"
}