Testing whether or not a Lookup object has access to members

[Mandy Chung]

You can submit from https://bugreport.java.com/bugreport/

Mandy

On 10/26/18 2:48 AM, Kasper Nielsen wrote:
> Hi Mandy,
>
> I don't have access to JBS unfortunately.
>
> Cheers
>   Kasper
>
> On Wed, 24 Oct 2018 at 16:50, Mandy Chung <mandy.chung at oracle.com 
> <mailto:mandy.chung at oracle.com>> wrote:
>
>     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
>>
>