feat: payload util methods

[Anush008]

This PR intends to payload util methods and unit tests for easy interop between java maps. Supports nested maps and arrays.

Example usage:

Map<String, Object> map = new HashMap<>();
map.put("name", "John Doe");
map.put("age", 42);
map.put("married", true);

Map<String, Value> payload = PayloadUtil.toPayload(map);

Reciprocal

Map<String, Object> mapAgain = PayloadUtil.toMap(payload);

[russcam]

I'm a little weary of adding utility methods that don't control invariants in public packages. For example,

toPayload(Map<String, Object> inputMap) { ... }

Allows any Object entry value. Consequently,

1. It silently ignores types that aren't supported by Value (it could throw instead)
2. It throws for Maps that have entry keys other than String

With the methods in ValueFactory, it's a little more convenient to build payloads e.g.

Map<String, Value> map = Map.of(
  "foo", value("bar"),
  "baz", value(1),
  "quux", list(List.of(value(true), value(false)))
);

Do you feel strongly about supporting conversion to/from Map<String,Object> in addition? If you do, what do you think about a specialized PayloadMap type with overloaded methods for the supported types?

[russcam]

initialize with the expected size (avoid allocation on resizing)

Suggested change

	Map<String, Value> map = new HashMap<>();
	Map<String, Value> map = new HashMap<>(inputMap.size());

[russcam]

initialize with the expected size (avoid allocation on resizing)

Suggested change

	Map<String, Object> hashMap = new HashMap<>();
	Map<String, Object> hashMap = new HashMap<>(payload.size());

[russcam]

WDYT about making this function pure?

Suggested change

	static void setValue(Value.Builder valueBuilder, Object value) {
	static Value toValue(Object value) {

[russcam]

Would a List<T> be more appropriate? It would be congruent with the inverse operation, List<T> -> ListValue

Suggested change

	return listValue.getValuesList().stream().map(PayloadUtil::valueToObject).toArray();
	return listValue.getValuesList().stream().map(PayloadUtil::valueToObject).collect(Collectors.toList());

[russcam]

This will throw an exception for any key that isn't a String

[Anush008]

I'm a little weary of adding utility methods that don't control invariants in public packages. For example,

toPayload(Map<String, Object> inputMap) { ... }

Allows any Object entry value. Consequently,

1. It silently ignores types that aren't supported by Value (it could throw instead)
2. It throws for Maps that have entry keys other than String

With the methods in ValueFactory, it's a little more convenient to build payloads e.g.

Map<String, Value> map = Map.of(
  "foo", value("bar"),
  "baz", value(1),
  "quux", list(List.of(value(true), value(false)))
);

Do you feel strongly about supporting conversion to/from Map<String,Object> in addition? If you do, what do you think about a specialized PayloadMap type with overloaded methods for the supported types?

Great points. I too now don't see any clear benefit of using this utility with exceptions over the Map.of() usage you presented.

[Anush008]

Closing with reference to #11 (comment).