Inline Record

[forax at univ-mlv.fr]

yes, 
an inline should use Object.equals and Object.hashCode. 

There is still an issue with the reference projection vs java.lang.Record. 
An inline record can not insert a ref projection because java.lang.Record as to be the sole super type. 

With the current compiler, this code compiles 
inline record RecordPoint(int x, int y) { 
public boolean equals(Object o) { 
return this == o; 
} 
public int hashCode() { 
return System.identityHashCode(this); 
} 
public String toString() { 
return "Point"; 
} 
} 

but there is a class format error on the ref projection 
java.lang.ClassFormatError: Record attribute in non-final or abstract class file fr/umlv/valuetype/RecordPoint$ref 

Rémi 

> De: "Brian Goetz" <brian.goetz at oracle.com>
> À: "John Rose" <john.r.rose at oracle.com>
> Cc: "Remi Forax" <forax at univ-mlv.fr>, "Srikanth"
> <srikanth.adayapalam at oracle.com>, "amber-dev" <amber-dev at openjdk.java.net>
> Envoyé: Jeudi 7 Mai 2020 15:47:07
> Objet: Re: Inline Record

> The implementation in Object is

> public boolean equals(Object obj) {
> return (this == obj);
> }

> This _already_ has exactly the default semantics we want for both inlines and
> identities. Records layer their implementation atop it, regardless of
> inline-ness.

> On 5/6/2020 7:11 PM, John Rose wrote:

>> On May 6, 2020, at 3:42 PM, Brian Goetz < [ mailto:brian.goetz at oracle.com |
>> brian.goetz at oracle.com ] > wrote:

>>> Eventually, inline classes will inherit eq/hashCode from Object.

>> Crazy half-baked idea of the moment:

>> Factor the equals/hashCode/toString methods for records into
>> static methods (in ju.Objects) which are configurable appropriately,
>> and have a default configuration. Use ClassValue for performance.

>> Then define equals/hashCode/toString in jl.Object (yes, Object)
>> to call those methods, *when the receiver is a Record and/or an inline*.

>> Two ideas here: 1. No per-class indy or BSM at all, but a ClassValue
>> instead. (We should do this for Record anyway.) 2. Push the specification
>> all the way up to Object. (2 makes more sense for inlines than for
>> Record, since it’s natural to define equals/hashCode/toString in
>> the class hierarchy, if there’s a place to put it. There isn’t for inlines.)

>> — John