On Wed, 31 Mar 2021 18:32:31 GMT, Mandy Chung <mch...@openjdk.org> wrote:
>> Hi Mandy, I have updated the PR with a revised version of the text above. Is >> that more in line what you had in mind? >> >> best regards, >> -- daniel > > This looks better. I like a separate mapping section for records since the > mapping rules are straight-forward. The complexity comes if we want to > support a record to implement `CompositeDataView` that allows a type to > support more flexible conversion to `CompositeData` which is why you add > records in the "Mappings for other types". I am wondering if we really want > to support records to implement `CompositeDataView` but we may want to avoid > such a special case. > > I suggest add subsections in "Mappings for other types": There are two > mapping rules: (1) _opentype(J)_ maps `J` to `CompositeType` (2) > _opendata(J)_ maps `J` to `CompositeData`. _opentype(J)_ for record class > does not need to refer to other types. The common cases for _opendata(J)_ > for record class is using the canonical constructors. The other less common > cases like using non-canonical constructors and `CompositeDataView` can state > that it follows the same rules as specified for other types. "Mappings for > other types" does not need any change for records. > > "Reconstructing an instance of Java type J from a CompositeData" section > should be renamed to "Reconstructing an instance of Java type or record class > J from a CompositeData" > > Here is a minor tweaking on "Mappings for Records" > > A record is convertible to a CompositeType if and only if all its components > are > convertible to open types. Otherwise, it is not convertible. > > A record class is converted to a CompositeType with one item for every record > component as follows. > - The type name of this CompositeType is determined by the type name rules > detailed below. > - Each record component of type T, the item in the CompositeType has the same > name > as the record component and of type opentype(T). > > The mapping from an instance of a record class to a CompositeData > corresponding to > the CompositeType is the same as specified as for other types (add a link). > > A record is reconstructed from a CompositeData using its canonical > constructor. > The canonical constructor doesn't require the presence of > @javax.management.ConstructorParameters > or @java.beans.ConstructorProperties annotations. If these annotations are > present on > the canonical constructor, they will be ignored. > > If the CompositeData from which the record is reconstructed doesn't contain > all the record components, > the MXBean framework will attempt to reconstruct the record in the same way > as specified for > other types (add a link). I have updated the PR with those changes, plus a few minor adjustments. ------------- PR: https://git.openjdk.java.net/jdk/pull/3201
