> On Jun 16, 2016, at 12:29 PM, Mandy Chung <[email protected]> wrote:
>
> Can you elaborate how proxy and default methods affects your library to able
> to run with security manager?
So in this particular case, I wanted to create an interface type where some
methods are automatically generated
from declarative annotations and some are not.
interface MyDao {
@SqlQuery("SELECT count(1) FROM table WHERE state='foo'")
int getFooCount();
@SqlQuery("SELECT count(1) FROM table WHERE state='bar'")
int getBarCount();
@InTransaction
default getFooAndBarCount() {
return getFooCount() + getBarCount();
}
}
Another use case I have, generating configuration beans from properties:
interface SomeConfig {
@Config("key.a")
int getA(); // required
@Config("key.b")
default int getB() {
return 3; // a nice way to specify the default value
}
}
Neither of these are impossible to work around. But I think the list of
situations
where this is useful is long and mostly not explored because it is very hard
to do so today :)
(Specifically about the security manager comment, I am using the workaround
outlined
in this thread which involves calling setAccessible on the MethodHandle
constructor
to avoid the unreflectSpecial security check.)
>
> This is a good enhancement. I have created a JBS issue to track that [1].
> There is no such existing enhancement request in JBS.
>
> Mandy
> [1] https://bugs.openjdk.java.net/browse/JDK-8159746
>
>> On Jun 16, 2016, at 11:14 AM, Steven Schlansker <[email protected]>
>> wrote:
>>
>> Hi everyone,
>>
>> I am glad this was discussed on the list again.
>> I just wanted to throw out there, as a library developer and
>> end user, I now have had to reproduce this hack in no fewer
>> than four different projects for various reasons.
>>
>> It is even worse because it means that my library cannot run
>> under a SecurityManager. While this isn't a problem for me
>> personally it does limit the utility of any libraries I might produce.
>>
>> It really is a glaring missing API and if it does not make Java 9
>> I can't imagine I will be the only person that is extremely disappointed.
>>
>> Thanks,
>> Steven
>>
>>> On Jun 6, 2016, at 1:58 PM, Mandy Chung <[email protected]> wrote:
>>>
>>> Hi Peter,
>>>
>>> Thanks for the proposal. This feature has been lacking. When this subject
>>> was brought, I also have similiar thought to provide a way in Proxy class
>>> for InvocationHandler to invoke a default method (but of course no time to
>>> put into it).
>>>
>>> I appreciate your contribution and good work. I support to add this
>>> feature in a future release.
>>>
>>> I personally don’t feel comfortable to absorb this small API targetting for
>>> JDK 9 (since I don’t have the cycle to shepherd this in the next few
>>> months). I may be overly conversative but I won’t take security assessment
>>> lightly. Maybe someone else is able to help you move this forward before I
>>> am available.
>>>
>>> Mandy
>>>
>>>> On Jun 3, 2016, at 7:58 AM, Peter Levart <[email protected]> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Since Java SE 8 introduced default methods in interfaces there was a
>>>> question what to do with java.lang.reflect.Proxy API. Nothing was done to
>>>> the API at that time, so the default behavior is to proxy default methods
>>>> too. InvocationHandler gets invoked for default methods, but it has not
>>>> provision to forward such calls to the default implementations in the
>>>> interfaces.
>>>>
>>>> I propose a simple API addition that allows calling super default methods
>>>> in proxy instances:
>>>>
>>>> http://cr.openjdk.java.net/~plevart/jdk9-dev/Proxy.invokeSuperDefaults/webrev.02/
>>>>
>>>> With this addition one can simply decide in the InvocationHandler what to
>>>> do with invocations to default methods and can forward such invocation to
>>>> the default implementation:
>>>>
>>>> public class Test {
>>>>
>>>> interface I1 {
>>>> default void m() {
>>>> System.out.println(" default I1.m() called");
>>>> }
>>>> }
>>>>
>>>> interface I2 {
>>>> default void m() {
>>>> System.out.println(" default I2.m() called");
>>>> }
>>>> }
>>>>
>>>> interface I12 extends I1, I2 {
>>>> @Override
>>>> void m();
>>>>
>>>> default int sum(int a, int b) {
>>>> return a + b;
>>>> }
>>>>
>>>> default Object[] concat(Object first, Object... rest) {
>>>> Object[] result = new Object[1 + rest.length];
>>>> result[0] = first;
>>>> System.arraycopy(rest, 0, result, 1, rest.length);
>>>> return result;
>>>> }
>>>> }
>>>>
>>>> public static void main(String[] args) {
>>>>
>>>> InvocationHandler h = (proxy, method, params) -> {
>>>> System.out.println("\nInvocationHandler called for: " + method +
>>>> " with parameters: " + Arrays.toString(params));
>>>> if (method.isDefault()) {
>>>> try {
>>>> return Proxy.invokeSuper(proxy, method, params);
>>>> } catch (InvocationTargetException e) {
>>>> throw e.getCause();
>>>> }
>>>> } else {
>>>> switch (method.getName()) {
>>>> case "m":
>>>> System.out.println(" abstract I12.m(): called");
>>>> return null;
>>>> default:
>>>> throw new UnsupportedOperationException(
>>>> "Unsupported method: " + method);
>>>> }
>>>> }
>>>> };
>>>>
>>>> I1 i1 = (I1) Proxy.newProxyInstance(
>>>> I1.class.getClassLoader(), new Class<?>[]{I1.class}, h);
>>>> i1.m();
>>>>
>>>> I2 i2 = (I2) Proxy.newProxyInstance(
>>>> I2.class.getClassLoader(), new Class<?>[]{I2.class}, h);
>>>> i2.m();
>>>>
>>>> I12 i12 = (I12) Proxy.newProxyInstance(
>>>> I12.class.getClassLoader(), new Class<?>[]{I12.class}, h);
>>>> i12.m();
>>>>
>>>> System.out.println(" 1 + 2 = " + i12.sum(1, 2));
>>>> System.out.println(" [1] concat [2, 3, 4] = " +
>>>> Arrays.toString(i12.concat(1, 2, 3, 4)));
>>>> }
>>>> }
>>>>
>>>>
>>>> I know FC date is over, but this is really a small change and I have heard
>>>> several people that such feature is missing from the Proxy API.
>>>>
>>>> I'm prepared to create jtreg tests covering the specification if this
>>>> proposal is accepted.
>>>>
>>>> Regards, Peter
>>>>
>>>>
>>>>
>>>
>>
>
