ValueType.findConstructor

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Fri Jun 23 23:31:18 UTC 2017


Maybe a naive question - but do you need method handle builder (and 
extra bytecode spinning) for constructor? Can't we combine the result of 
findConstructor on the boxed class with the vunbox MH?

Maurizio


On 23/06/17 23:17, Paul Sandoz wrote:
> Hi,
>
> This adds a findConstructor method to ValueType:
>
>    http://cr.openjdk.java.net/~psandoz/valhalla/find-constructor/webrev/ <http://cr.openjdk.java.net/~psandoz/valhalla/find-constructor/webrev/>
>
>>
> Next steps are to investigate re-construction: taking an existing value, one or more explicit component values, and constructing a new value by merging the implicit components of the existing value and the explicit component values. It’s a bit like one or more vwithfield calls but would go through a constructor and perform argument checks etc.
>
> The tricky aspect is reliably extracting out the component values and in a known order so they can be passed as arguments to the VCC constructor.
>
> For MVT i think we can define something useful even if it is a little fragile, so was to make construction easier.
>
> (There are also potential short-cuts if there is no explicit constructor and fields are either initialized to default or some other values, as i think vnew could be used directly for construction).
>
> Paul.



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