Retrieve Parent node element from Json

Question

I want to retrieve parent element along with the child element while filtering.
Please find the below XML:

    {
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },a
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
    "expensive": 10
}

When I give the below expression it gives only the child element as output:

Expression:
$.store.book[?(@.category== 'fiction')]
Output:
[
   {
      "category" : "fiction",
      "author" : "Evelyn Waugh",
      "title" : "Sword of Honour",
      "price" : 12.99
   },
   {
      "category" : "fiction",
      "author" : "Herman Melville",
      "title" : "Moby Dick",
      "isbn" : "0-553-21311-3",
      "price" : 8.99
   },
   {
      "category" : "fiction",
      "author" : "J. R. R. Tolkien",
      "title" : "The Lord of the Rings",
      "isbn" : "0-395-19395-8",
      "price" : 22.99
   }
]

Expected Output should be:

 {
    "store": {
        "book": [ then the below elements

[
   {
      "category" : "fiction",
      "author" : "Evelyn Waugh",
      "title" : "Sword of Honour",
      "price" : 12.99
   },
   {
      "category" : "fiction",
      "author" : "Herman Melville",
      "title" : "Moby Dick",
      "isbn" : "0-553-21311-3",
      "price" : 8.99
   },
   {
      "category" : "fiction",
      "author" : "J. R. R. Tolkien",
      "title" : "The Lord of the Rings",
      "isbn" : "0-395-19395-8",
      "price" : 22.99
   }
]

Please help me with any alternatives using java along with the code snippet.

score 0 · Answer 1 · answered Jun 16 '21 at 18:05

Unfortunately, this feature is not implemented yet (as of now): See this collective issue on Github.

However, I believe even if the library would allow you to get the parent node by child nodes you would not get the expected result. For instance, JsonPath-Plus (JS) allow you to go up one (or more) nodes in the hierarchy using the ^ operator. However, if you have moved up you will get everything below that node, which would defeat the purpose of filtering in your case but may work in other scenarios.

The easiest fix might be to add the "wrapping" JSON header/footer back after you have filtered, maybe by using string operations. If you don't like that you could look into JSON transformers instead. JOLT is a common one in the Java world but there are more.

Retrieve Parent node element from Json

1 Answers1