JSON Parsing problem

Question

Hey, Im trying to parse the following JSON data:

{"chat":
{"link":
[{"@rel":"next","@ref":"http"}],
"events":
{"link2":
[{"@rel":"next","@ref":"http"}]}
}}

The code that reads the data is (where 'a' is the JSON as String):

  JSONObject jsonObject1 = new JSONObject(a);
  JSONObject jsonObject = jsonObject1.getJSONObject("chat");

So the structure (at least the way I intended) is:

<chat>
    <link>
    <events>
        <link2>
    </events>
</chat<

But, after getJsonObject("chat"), jsonObject equals to:

{"chat":{"events":{"link2":[{"@ref":"http","@rel":"next"}]},"link":[{"@ref":"http","@rel":"next"}]}}

What am I missing? Why does the data flips and the structure changes?

"Why does the data flips and the structure changes?" I don't see any structure changes, just "data flips" (e.g., changes in the order in which the properties are shown). As msalvadores points out below, there is no order to the properties in an object represented by JSON. (From the JSON site: "An object is an unordered set of name/value pairs") To have order, you must use an ordering construct (such as an array). Since the only arrays in your structure only have one element, it's not evident from the above, but array entries are ordered and so won't be moved around. — T.J. Crowder
– T.J. Crowder, Commented May 2, 2011 at 11:08
@Lucero: Well, it's mostly just an extension of msalvadores' answer, which is why I commented rather than answering. Really, what I should have done / should do is edit msalvadores' answer to add the link and quote or something, as StackOverflow is meant to be collaborative. But I'm really cautious about doing that (and most people seem to be, probably more cautious than Jeff originally planned). Edit: And I've done that now, we should all be more willing to make good answers even better. — T.J. Crowder
– T.J. Crowder, Commented May 2, 2011 at 11:18

T.J. Crowder · Accepted Answer · 2011-05-02 11:20:59Z

3

The properties in a JSON object are not sorted. From the JSON site:

An object is an unordered set of name/value pairs...

(My emphasis) Therefore the position of link and event are irrelevant for the parser. Bottom line, link and event are at the same level therefore they can be shifted and wherever order matters use arrays in JSON ... [].

edited May 2, 2011 at 11:20

T.J. Crowder

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answered May 2, 2011 at 11:03

Manuel Salvadores

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