[GitHub] [commons-geometry] singhbaljit commented on a change in pull request #122: Miscellaneous (cherry-picked) improvements

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

singhbaljit commented on a change in pull request #122:
URL: https://github.com/apache/commons-geometry/pull/122#discussion_r547330636



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File path: commons-geometry-core/src/main/java/org/apache/commons/geometry/core/partitioning/AbstractConvexHyperplaneBoundedRegion.java
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@@ -161,7 +161,7 @@ public String toString() {
      */
     protected <R extends AbstractConvexHyperplaneBoundedRegion<P, S>> R transformInternal(
             final Transform<P> transform, final R thisInstance, final Class<S> boundaryType,
-            final Function<List<S>, R> factory) {
+            final Function<? super List<S>, R> factory) {

Review comment:
       IMO, it improves the usability of the APIs. See Josh Bloch's _Effective Java_ (3rd Edition):
   
   > Using wildcard types in your APIs, while tricky, makes the APIs far more flexible. If you write a library that will be widely used, the proper use of wildcard types should be considered mandatory.
   
   Actually, some of the generic parameters can also wildcards (i.e. `final Class<? extends S> boundaryType`), but I kept those out for now to avoid overcomplicating the signature even more.




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