[CONFIGURATION-686] JSONConfiguration doesn't support array of objects

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2
• Fix Version/s: 2.3
• Assignee: Unassigned
• Reporter: Vincent Maurin
• Created: 27/Dec/17 16:48
• Updated: 08/Aug/18 20:28
• Resolved: 02/Jan/18 20:01

Description

Hello,

I have noticed that the array type is not properly handled by the JSONConfiguration (or AbstractYAMLBasedConfiguration)

If we take the example from json.org

{
  "menu": {
    "id": "file",
    "value": "File",
    "popup": {
      "menuitem": [
        {
          "value": "New",
          "onclick": "CreateNewDoc()"
        },
        {
          "value": "Open",
          "onclick": "OpenDoc()"
        },
        {
          "value": "Close",
          "onclick": "CloseDoc()"
        }
      ]
    }
  }
}

I would have expect the following call to return "New"

configuration.getString("menu.popup.menuitem(0).value")

The issue, I guess, is that only the Map type is handled by AbstractYAMLBasedConfiguration in a recursive way and not the list type.

I had a custom JSONConfiguration implementation before supporting this use case, sorry for the code, it could be a bit messy and old, but it is maybe clearer to understand my issue

@Override
    @SuppressWarnings("unchecked")
    public void read(Reader in) throws ConfigurationException {
        try {
            Object jsonRoot = MAPPER.readValue(in, Object.class);
            List<ImmutableNode.Builder> roots = createHierarchy(jsonRoot);
            if (roots.size() != 1) {
                throw new ConfigurationException("The configuration only support a single root");
            }
            getSubConfigurationParentModel().mergeRoot(roots.get(0).create(), null, null, null, null);
        } catch (IOException ex) {
            throw new ConfigurationException("Invalid JsonConfiguration", ex);
        }
    }
 
    @SuppressWarnings("unchecked")
    private static List<ImmutableNode.Builder> createHierarchy(Object value) {
        if (value instanceof Map) {
            ImmutableNode.Builder result = new ImmutableNode.Builder();
            Map<String, ?> map = (Map<String, ?>) value;
            for (Map.Entry<String, ?> entry : map.entrySet()) {
                List<ImmutableNode.Builder> children = createHierarchy(entry.getValue());
                for (ImmutableNode.Builder child : children) {
                    child.name(entry.getKey());
                    result.addChild(child.create());
                }
            }
            return Collections.singletonList(result);
        } else if (value instanceof List) {
            List list = (List) value;
            List<ImmutableNode.Builder> result = new ArrayList<>(list.size());
            for (Object item : list) {
                List<ImmutableNode.Builder> children = createHierarchy(item);
                for (ImmutableNode.Builder child : children) {
                    result.add(child);
                }
            }
            return result;
        }
        ImmutableNode.Builder result = new ImmutableNode.Builder();
        result.value(value);
        return Collections.singletonList(result);
    }