[EDGENT-407] JsonFunctions: more convenience functions for creation and unpartitioned window

• Type: Wish
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Apache Edgent 1.2.0
• Component/s: API
• Assignee: Dale LaBossiere
• Reporter: Dale LaBossiere
• Created: 13/Apr/17 14:19
• Updated: 02/Jan/18 18:58
• Resolved: 19/Apr/17 20:20

Description

Recently I've found myself repetitively doing the following when transforming a stream of simple numerics into a JsonObject (e.g., for publishing via IotDevice(TStream<JsonObject>)):

TStream<Double> s = ...
TStream<JsonObject> js = s.map(val -> {
  JsonObject jo = new JsonObject();
  jo.addProperty("propName", val);
  return jo.
});

Unfortunately, addProperty() returns void so the above can't be reduced to something like:

return new JsonObject().addProperty("propName", val)

I'd like an ease-of-use function like:

TStream<JsonObject> js = s.map(JsonFunctions.valueOfNumber("propName"));

For completeness, there should also be valueOfString(), valueOfCharacter(), valueOfBoolean().

Also, JsonAnalytics works with JsonElement partitioned windows: TWindow<JsonObject,JsonElement>. It should be trivial to be able to specify an unpartitioned window. Functions.unpartitioned() provides that for Integer keyed windows. There should be a corresponding JsonFunctions.unpartitioned().