Testing whether or not a Lookup object has access to members

[Mandy Chung]

Can you file a JBS issue?

Mandy

On 10/23/18 12:15 PM, Kasper Nielsen wrote:
> Hi Mandy,
>
> Yes, that it was my code is doing now, I unreflect a member and then 
> test if an exception is thrown.
> However, it is just a bit of an antipattern, catching exception to 
> test a condition.
>
> I would prefer if something like this was available:
> boolean Lookup.isAccessible(Member member)
> boolean Lookup.isAccessible(Class<?> member)
>
>
> /Kasper
>
> On Tue, 23 Oct 2018 at 00:07, Mandy Chung <mandy.chung at oracle.com 
> <mailto:mandy.chung at oracle.com>> wrote:
>
>     Lookup.accessClass(member.getDeclaringClass()) can be used to test
>     if the lookup class can access the declaring class of the given
>     member.
>     This only checks if a class is accessible.  I think unreflecting a
>     member
>     will do what you are looking for to check if the lookup object has
>     access
>     to the member.  What does the code do if the Lookup object has access
>     vs has no access?
>
>     Mandy
>
>     On 10/22/18 1:17 PM, Kasper Nielsen wrote:
>>     Hi,
>>
>>     Are there any elegant way to test if a Lookup object has access to a member
>>     (field, constructor, method). Right now I'm using the following code
>>
>>     public static boolean hasAccess(MethodHandles.Lookup lookup, Member member)
>>     {
>>
>>          if (member instanceof Constructor) {
>>
>>              try {
>>
>>                  lookup.unreflectConstructor((Constructor<?>) member);
>>
>>              } catch (IllegalAccessException e) {
>>
>>                  return false;
>>
>>              }
>>
>>          } else if (member instanceof Method) {
>>
>>              try {
>>
>>                  lookup.unreflect((Method) member);
>>
>>              } catch (IllegalAccessException e) {
>>
>>                  return false;
>>
>>              }
>>
>>          } else if (member instanceof Field) {
>>
>>              try {
>>
>>                  lookup.unreflectVarHandle((Field) member);
>>
>>              } catch (IllegalAccessException e) {
>>
>>                  return false;
>>
>>              }
>>
>>          }
>>
>>          return true;
>>
>>     }
>>
>>     Cheers
>>        Kasper
>