Review Request JDK-8186050: StackFrame should provide the method signature

[forax at univ-mlv.fr]

Hi Mandy,
good for me.

in Basic.java, in methodTypes(), instead of using a new HashMap, you can use Map.of().

cheers,
Rémi

----- Mail original -----
> De: "mandy chung" <mandy.chung at oracle.com>
> À: "Remi Forax" <forax at univ-mlv.fr>
> Cc: "core-libs-dev" <core-libs-dev at openjdk.java.net>
> Envoyé: Vendredi 1 Septembre 2017 07:39:54
> Objet: Re: Review Request JDK-8186050: StackFrame should provide the method signature

> Updated webrev:
> http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8186050/webrev.01/index.html
> 
> This introduces two new methods, StackFrame::getMethodType and
> StackFrame::getDescriptor.
> 
> Mandy
> 
> On 8/30/17 12:25 AM, Remi Forax wrote:
>> Hi Mandy,
>> thanks for taking care of this.
>>
>> In my opinion, we should provide both getMethodType() and getDescriptor(),
>> getDescriptor() is handy for logging (finding the right overload when line
>> numbers are not present) and getMethodType() is the one you whant if you want
>> to inspect the runtime view of the stack frames (and by example interact with
>> java.lang.invoke). For me, it's the same reason that give us
>> getDeclaringClass() and getClassName() in the current API.
>>
>> So getDescriptor() can be called with no restriction but getMethodType()
>> requires RETAIN_CLASS_REFERENCE.
>>
>> regards,
>> Rémi
>>
>> ----- Mail original -----
>>> De: "mandy chung" <mandy.chung at oracle.com>
>>> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
>>> Envoyé: Mardi 29 Août 2017 00:57:28
>>> Objet: Review Request JDK-8186050: StackFrame should provide the method
>>> signature
>>> Method signature is missing in the StackFrame API. This proposes to add
>>> StackFrame::getMethodDescriptor method to return the method descriptor
>>> in a stack frame.
>>>
>>> Webrev at:
>>> http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8186050/webrev.00/index.html
>>>
>>> There are a couple options how to present the method signature in the
>>> API level:
>>> 1. Class<?>[] getParameterTypes() and Class<?> getReturnTypes() similiar
>>> to what java.lang.reflect.Method has.
>>> 2. java.lang.invoke.MethodType
>>> 3. a String representation (i) comma-separated list of the method's
>>> formal parameter types (ii) bytecode method descriptor as specified in JVMS
>>>
>>> Returning Class<?> instance should require to add a new StackWalker
>>> option to access to the parameter types and return type for option #1
>>> and #2. StackFrame::getDeclaringClass requires the stack walker to have
>>> the RETAIN_CLASS_REFERENCE capability.
>>>
>>> Option #2 returning MethodType is handy while java.lang would reference
>>> a type in java.lang.invoke.
>>>
>>> Option #3 requires the caller to parse the return string and call
>>> Class.forName to get the Class<?> instance. OTOH
>>> MethodType::fromMethodDescriptorString method that returns MethodType
>>> from a bytecode method descriptor string.
>>>
>>> Method signature is for information for typical cases. Getting Class<?>
>>> for the parameter types and return type would be a niche case. I think
>>> returning the method descriptor string is a good option - keep the API
>>> simple and can use MethodType::fromMethodDescriptorString to get back
>>> the types if needed.
>>>
>>> thanks
> >> Mandy