REPL code review

[Robert Field]

On 09/11/15 08:25, Maurizio Cimadamore wrote:
>
> * MemoryFileManager
>
>    - Maybe the code of 'list' could be more optimized/lazy by 
> returning a compound iterator - i.e. an iterator that keeps scanning 
> the items in the first iterator and, when finished moves onto the next 
> iterator.

How's this?  It could be more or less lazy: "it" could be pre-filled, or 
"stdList" could be called at the last minute.

     @Override
     public Iterable<JavaFileObject> list(JavaFileManager.Location location,
             String packageName,
             Set<JavaFileObject.Kind> kinds,
             boolean recurse)
             throws IOException {
         Iterable<JavaFileObject> stdList = 
stdFileManager.list(location, packageName, kinds, recurse);
         if (location==CLASS_PATH && packageName.equals("REPL")) {
             // if the desired list is for our JShell package, lazily 
iterate over
             // first the standard list then any generated classes.
             return () -> new Iterator<JavaFileObject>() {
                 boolean stdDone = false;
                 Iterator<? extends JavaFileObject> it;

                 @Override
                 public boolean hasNext() {
                     if (it == null) {
                         it = stdList.iterator();
                     }
                     if (it.hasNext()) {
                         return true;
                     }
                     if (stdDone) {
                         return false;
                     } else {
                         stdDone = true;
                         it = generatedClasses().iterator();
                         return it.hasNext();
                     }
                 }

                 @Override
                 public JavaFileObject next() {
                     if (!hasNext()) {
                         throw new NoSuchElementException();
                     }
                     return it.next();
                 }

             };
         } else {
             return stdList;
         }
     }

>
>    - comments: is it normal to repeat all comments from the 
> JavaFileManager interface?

I don't think it is normal.

I've found it very useful to have them there both during implementation 
and maintenance.  If you feel they should be removed, I will.

>
>    - watch out for unused methods: dumpClasses, findGeneratedClass, 
> findGeneratedBytes, inferModuleName, listModueLocations (maybe this 
> stuff is for Jigsaw? If so, maybe add a comment) 

I've added comment (in my local repo).

     // For debugging dumps
dumpClasses

     // For restoring process-local execution support
findGeneratedClass, findGeneratedBytes
and several others

     // Make compatible with Jigsaw
inferModuleName, listModueLocations

Thanks,
Robert