Use Method.getParameterCount() where possible

[Claes Redestad]

Hi,

looks good and trivial to me. I'll sponsor.

/Claes

(I hope we can wrap up https://bugs.openjdk.java.net/browse/JDK-8029019
some day, soon)

On 2020-04-03 12:19, Christoph Dreis wrote:
> Hi,
> 
> I noticed that the JDK itself still uses Method.getParameterTypes().length in a couple of places.
> 
> This could be replaced with Method.getParameterCount() to avoid unnecessary cloning overhead.
> While this is often optimized away, I guess it's still good to not rely on that. Additionally, it's a little more concise to read.
> 
> If you think this is worthwhile, I would need someone to sponsor that tiny change.
> 
> P.S.: There is another occurrence in ForkJoinTask where I wasn't sure if I should change that, because it's usually changed under the JSR166 umbrella afaik.
> 
> Cheers,
> Christoph
> 
> ==== PATCH ====
> 
> diff --git a/src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java b/src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java
> --- a/src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java
> +++ b/src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java
> @@ -276,13 +276,13 @@
>           switch (m.getName()) {
>           case "toString":
>               return (m.getReturnType() == String.class
> -                    && m.getParameterTypes().length == 0);
> +                    && m.getParameterCount() == 0);
>           case "hashCode":
>               return (m.getReturnType() == int.class
> -                    && m.getParameterTypes().length == 0);
> +                    && m.getParameterCount() == 0);
>           case "equals":
>               return (m.getReturnType() == boolean.class
> -                    && m.getParameterTypes().length == 1
> +                    && m.getParameterCount() == 1
>                       && m.getParameterTypes()[0] == Object.class);
>           }
>           return false;
> diff --git a/src/java.base/share/classes/java/lang/reflect/Executable.java b/src/java.base/share/classes/java/lang/reflect/Executable.java
> --- a/src/java.base/share/classes/java/lang/reflect/Executable.java
> +++ b/src/java.base/share/classes/java/lang/reflect/Executable.java
> @@ -378,7 +378,7 @@
>       private void verifyParameters(final Parameter[] parameters) {
>           final int mask = Modifier.FINAL | Modifier.SYNTHETIC | Modifier.MANDATED;
> 
> -        if (getParameterTypes().length != parameters.length)
> +        if (getParameterCount() != parameters.length)
>               throw new MalformedParametersException("Wrong number of parameters in MethodParameters attribute");
> 
>           for (Parameter parameter : parameters) {
> diff --git a/src/java.base/share/classes/sun/reflect/annotation/AnnotationType.java b/src/java.base/share/classes/sun/reflect/annotation/AnnotationType.java
> --- a/src/java.base/share/classes/sun/reflect/annotation/AnnotationType.java
> +++ b/src/java.base/share/classes/sun/reflect/annotation/AnnotationType.java
> @@ -121,7 +121,7 @@
>               if (Modifier.isPublic(method.getModifiers()) &&
>                   Modifier.isAbstract(method.getModifiers()) &&
>                   !method.isSynthetic()) {
> -                if (method.getParameterTypes().length != 0) {
> +                if (method.getParameterCount() != 0) {
>                       throw new IllegalArgumentException(method + " has params");
>                   }
>                   String name = method.getName();
> 
>