RFR: JDK-8235621: Replace use of Function<?,Integer> with ToIntFunction

[Remi Forax]

Hi Jonathan,
for addExtraAttributes, the method should be

  public void addExtraAttributes(ToIntFunction<? super Symbol> addExtraAttributes) {

for the same reason a public method should take a List and not an ArrayList, so you can call it with
  addExtraAttributes((Object o) -> 12);
if the attribute is constant.

If addExtraAttributes takes a ToIntFunction<? super Symbol>, you will have to use ToIntFunction<? super Symbol> everywhere.

I should propose a new JEP to lock Dan Smith into a prison until JEP 300 [1] is delivered, because we will be able to get ride of most of those pesky wildcards (at least all the ones on functional interfaces) if that JEP is delivered.

regards,
Rémi

[1] https://openjdk.java.net/jeps/300

----- Mail original -----
> De: "jonathan gibbons" <jonathan.gibbons at oracle.com>
> À: "compiler-dev" <compiler-dev at openjdk.java.net>
> Envoyé: Mardi 10 Décembre 2019 01:38:44
> Objet: RFR: JDK-8235621: Replace use of Function<?,Integer> with ToIntFunction

> Following Rémi's suggestion[1], please review a trivial change to javac
> to have it use ToIntFunction
> instead of Function<..., Integer> in the recent patch for JDK-8234689 [2].
> 
> Patch inline below. No change to the original test is necessary.
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8235621
> [1]
> https://mail.openjdk.java.net/pipermail/compiler-dev/2019-December/014043.html
> [2] https://hg.openjdk.java.net/jdk/jdk/rev/17b0f051280f
> 
> -- Jon
> 
> diff -r 2aaa8bcb90a9 -r 1e000f399f3a
> src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java
> 
> ---
> a/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java
> Mon Dec 09 15:28:46 2019 +0100
> +++
> b/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java
> Mon Dec 09 16:12:42 2019 -0800
> @@ -30,7 +30,7 @@
>  import java.util.Map;
>  import java.util.Set;
>  import java.util.LinkedHashSet;
> -import java.util.function.Function;
> +import java.util.function.ToIntFunction;
> 
>  import javax.tools.JavaFileManager;
>  import javax.tools.FileObject;
> @@ -114,7 +114,7 @@
>       */
>      public boolean multiModuleMode;
> 
> -    private List<Function<Symbol, Integer>> extraAttributeHooks =
> List.nil();
> +    private List<ToIntFunction<Symbol>> extraAttributeHooks = List.nil();
> 
>      /** The initial sizes of the data and constant pool buffers.
>       *  Sizes are increased when buffers get full.
> @@ -191,7 +191,7 @@
>          }
>      }
> 
> -    public void addExtraAttributes(Function<Symbol, Integer>
> addExtraAttributes) {
> +    public void addExtraAttributes(ToIntFunction<Symbol>
> addExtraAttributes) {
>          extraAttributeHooks =
> extraAttributeHooks.prepend(addExtraAttributes);
>      }
> 
> @@ -1669,7 +1669,7 @@
>       */
>      protected int writeExtraAttributes(Symbol sym) {
>          int i = 0;
> -        for (Function<Symbol, Integer> hook : extraAttributeHooks) {
> +        for (ToIntFunction<Symbol> hook : extraAttributeHooks) {
>              i += hook.apply(sym);
>          }
>           return i;