RFR 8158131: Nashorn should not use jdk.internal.module.Modules API

[Michael Haupt]

Hi Sundar,

lower-case thumbs up for both the jdk and nashorn changes, with remarks:

== ModuleGraphManipulator.java ==

* please add a @see or @link to the place where the bytes are read and code is dynamically generated, or used, and vice versa.

== JavaAdapterBytecodeGenerator.java ==
 
+    private static final Module nashornModule = JavaAdapterBytecodeGenerator.class.getModule();

This borders on the emerging discipline of Jigsaw idioms and patterns ... assuming this class moves, at some point in the future, to another (internal?) module. This will itch. How about having one central authority saying "I represent the Nashorn module", rather than implicitly assuming the class at hand will be in that module forever? One line below, Object.class.getModule() looks like a waterproof representative for the java.base module.

+    private static byte[] MODULES_READ_ADDER_BYRES;

If it cannot be final, how about @Stable? It would help, if not in terms of performance, so at least to document that this is an array that will be populated *once* and never change thereafter.

+        // private static final Module myModule;
+        {
+            FieldVisitor fv = cw.visitField(ACC_PRIVATE | ACC_FINAL | ACC_STATIC,
+                "myModule", "Ljava/lang/reflect/Module;", null, null);
+            fv.visitEnd();
+        }

Suggestion: adhere to Java coding style even in generated code and spell this as MY_MODULE.

Best,

Michael

> Am 30.05.2016 um 10:24 schrieb Sundararajan Athijegannathan <sundararajan.athijegannathan at oracle.com>:
> 
> Please review http://cr.openjdk.java.net/~sundar/8158131/ for
> https://bugs.openjdk.java.net/browse/JDK-8158131
> 
> This code cleanup is to avoid Nashorn's use of JDK internal class
> jdk.internal.module.Modules.
> 
> With this change, nashorn uses java.lang.reflect.Layer public API to
> create single Module layers as needed.  And nashorn generates/loads code
> into appropriate modules (which calls java.lang.reflect.Module.addReads,
> .addExports public APIs) to add module export/read edges as needed.
> 
> -Sundar
> 

-- 

 <http://www.oracle.com/>
Dr. Michael Haupt | Principal Member of Technical Staff
Phone: +49 331 200 7277 | Fax: +49 331 200 7561
Oracle Java Platform Group | LangTools Team | Nashorn
Oracle Deutschland B.V. & Co. KG | Schiffbauergasse 14 | 14467 Potsdam, Germany

ORACLE Deutschland B.V. & Co. KG | Hauptverwaltung: Riesstraße 25, D-80992 München
Registergericht: Amtsgericht München, HRA 95603

Komplementärin: ORACLE Deutschland Verwaltung B.V. | Hertogswetering 163/167, 3543 AS Utrecht, Niederlande
Handelsregister der Handelskammer Midden-Nederland, Nr. 30143697
Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher
 <http://www.oracle.com/commitment>	Oracle is committed to developing practices and products that help protect the environment