[GitHub] [commons-lang] kinow commented on a change in pull request #523: Rewrite the finding of matching Locales in LocaleUtils using the Streams API.

[GitBox <gi...@apache.org>]

kinow commented on a change in pull request #523:
URL: https://github.com/apache/commons-lang/pull/523#discussion_r411729884



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File path: src/main/java/org/apache/commons/lang3/LocaleUtils.java
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@@ -295,14 +297,13 @@ public static boolean isAvailableLocale(final Locale locale) {
         }
         List<Locale> langs = cLanguagesByCountry.get(countryCode);
         if (langs == null) {
-            langs = new ArrayList<>();
-            final List<Locale> locales = availableLocaleList();
-            for (final Locale locale : locales) {
-                if (countryCode.equals(locale.getCountry()) &&
-                    locale.getVariant().isEmpty()) {
-                    langs.add(locale);
-                }
-            }
+            // Allows Locales to be processed using multiple threads.
+            langs = availableLocaleList().parallelStream()

Review comment:
       From what I remember (sorry, been doing more Python these days), the `parallelStream` could be good or bad. For a low level library, I think it would be bad.
   
   That method starts executors in the background, and I think it's either a fixed number of executors, or based on the number of cores.
   
   But anyway, the point was that if a library uses `parallelStream`, users of the API would have to be aware that there could be small performance peaks due to these extra executors being created. See [this SO question & answers](https://stackoverflow.com/questions/20375176/should-i-always-use-a-parallel-stream-when-possible).
   
   The place where I would use it, would be some small command line utility processing text/files with thousands or millions of lines in a single computer. There I could perhaps use a parallelStream to do some processing.
   
   So for that, for now, I'd be -1 to `parallelStream` here in common (the code looks nicer by the way :)




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