@Property methods now implicitly override fields

[SentryMan]

• automatically disables field serialization if a @Property method targeting the same field is located (the getter method will serialize instead)
• can even change the type of the accessor

Now this:

@Json
public class OptionalAccess {

  String stringy;

  @Property("stringy")
  public Optional<String> stringy() {
    return Optional.of(stringy);
  }

  public void stringy(String stringy) {
    this.stringy = stringy;
  }
}

will generate like this:

public final class OptionalAccessJsonAdapter implements JsonAdapter<OptionalAccess> , ViewBuilderAware {
...

  private final JsonAdapter<String> stringJsonAdapter;
  private final JsonAdapter<Optional<String>> optionalStringJsonAdapter;
  private final PropertyNames names;

  public OptionalAccessJsonAdapter(Jsonb jsonb) {
    this.stringJsonAdapter = jsonb.adapter(String.class);
    this.optionalStringJsonAdapter = jsonb.adapter(Types.optionalOf(String.class));
    this.names = jsonb.properties("stringy");
  }
...

  @Override
  public void build(ViewBuilder builder, String name, MethodHandle handle) {
    builder.beginObject(name, handle);
    builder.add("stringy", optionalStringJsonAdapter, builder.method(OptionalAccess.class, "stringy", java.util.Optional.class));
    builder.endObject();
  }

  @Override
  public void toJson(JsonWriter writer, OptionalAccess optionalAccess) {
    writer.beginObject(names);
    writer.name(0);
    optionalStringJsonAdapter.toJson(writer, optionalAccess.stringy());
    writer.endObject();
  }

  @Override
  public OptionalAccess fromJson(JsonReader reader) {
    OptionalAccess _$optionalAccess = new OptionalAccess();

    // read json
    reader.beginObject(names);
    while (reader.hasNextField()) {
      final String fieldName = reader.nextField();
      switch (fieldName) {
        case "stringy": 
          _$optionalAccess.stringy(stringJsonAdapter.fromJson(reader));
          break;

        default:
          reader.unmappedField(fieldName);
          reader.skipValue();
      }
    }
    reader.endObject();

    return _$optionalAccess;
  }
}

part of #216

[Auties00]

I'll take a look this night to see if I can help add support for views, we might also want to consider OptionalInt, OptionaLong, OptionalDouble

[SentryMan]

found another way to do it.

[SentryMan]

Yeah, I'm good with this. @rbygrave please review when you get time