eclipse-aascw / aas-core-codegen / 35267724995

90%

Build Type

push

github

Committed by web-flow

Commit Message

Compose the Java JSON serialization (#710)

A list-typed property used to compose its serialization at the call
site, into a named temporary which the next line then handed over:

    if (that.getSupplementalSemanticIds().isPresent()) {
      final ArrayNode arraySupplementalSemanticIds = serializeArray(
        that.getSupplementalSemanticIds().get(),
        this::transform);
      result.set("supplementalSemanticIds", arraySupplementalSemanticIds);
    }

while every other property was a single statement:

    if (that.getSemanticId().isPresent()) {
      result.set("semanticId", transform(
        that.getSemanticId().get()));
    }

A list and a tuple are now named just like everything else, so all of
them are the same statement -- a key, and the value serialized by the
function of its kind:

    if (that.getSupplementalSemanticIds().isPresent()) {
      result.set("supplementalSemanticIds", serializeListOf_IClass(
        that.getSupplementalSemanticIds().get()));
    }

    if (that.getSemanticId().isPresent()) {
      result.set("semanticId", transformClass(that.getSemanticId().get()));
    }

``this::transform`` was the cost of composing at the call site. It is a
bound method reference, so it captures its receiver, and the JVM can not
cache it: it allocates a fresh instance on every evaluation, exactly as
much as the ``this``-capturing lambda it would have replaced. Measured
per call with ``getThreadAllocatedBytes``: a bound method reference and
a capturing lambda both cost 16 bytes, a static method reference and a
non-capturing lambda nothing. ``JsonNodeFactory.instance::textNode`` is
bound as well, so a list of primitives paid the same.

The transformer is therefore entered through ``transformClass``, a
static shim over a single stateless instance, which a composed
serializer -- static as well -- can reach:

    private static final _Transformer INSTANCE = new _Transformer();

    static JsonNode transformClass(IClass that) {
      return I... (continued)

Coverage Stats

156 of 156 new or added lines in 1 file covered. (100.0%)

1 existing line in 1 file now uncovered.

34366 of 40107 relevant lines covered (85.69%)

2.57 hits per line