Re: empty interfaces via reflection

From:

"Aryeh M. Friedman" <Aryeh.Friedman@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 14 Oct 2007 17:21:12 -0000

Message-ID:

<1192382472.231141.89080@q5g2000prf.googlegroups.com>

On Oct 14, 5:12 pm, Daniel Pitts
<newsgroup.spamfil...@virtualinfinity.net> wrote:

Aryeh M. Friedman wrote:

This is where the proxy comes in I basically wrap Proxy.invoke(....)
around all method calls and if the return type needs to be rebranded
(made by the custom classloader) it does so. This is safe because it
is conceptually illegal for a unit test to call any methods in the
returned value except to check it's values.

oops mentioned the one problem java.lang.reflect.Proxy requires all
acted on "classses" be interfaces not classes. thus the desire to
make a empty interface and wrap any rebranded class in it tempurarly
so the proxy can be used.

What you really need to do is NOT cast to an explicit object, but use
reflection to call your test hooks:

Class<?> testClass = loadTestClass();
Object testInstance = testClass.newInstance();
for (Method method: testClass.getDeclaredMethods()) {
method.invoke(testInstance, new Object[0]);

}

Then how do you handle the return type?!?!?!? Namely I can't do:

Class<?> testClass = loadTestClass();
Object testInstance = testClass.newInstance();
Result res=new Result();

for (Method method: testClass.getDeclaredMethods())
res.merge((Result) method.invoke(testInstance, new
Object[0])); // cast exception

reportResults(res)

....

private void reportResults(Result res)
{
.....
}

The reason why it is not possible is any Result object created by a
test is <MyClassLoader>.Result and all the results here are
<SystemClassLoader>.Result