Re: [Jython-users] Jython/Java and Reflection

[<bc...@wo...>]

[mike]

>I am running into a problem trying to subclass a java class from
>Jython2.0. The problem lies in the fact that the java class I extend from
>uses reflection to implement the template method pattern. The methods it is
>looking for is implemented in my jython class. Here is an example using the 
>JUnit framework which illustrates my problem:
>
>---- example.py ----
>import java
>import junit
>
>class MyJavaClassTest(junit.framework.TestCase):
>
>	def __init__(self, name):
>		junit.framework.TestCase.__init__(self, name)
>
>	def setUp(self):
>		"@sig public void setUp()"
>		pass
>
>	def testMyJavaClass(self):
>		"@sig public void testMyJavaClass()"
>		pass
>
>junit.textui.TestRunner.run(MyJavaClassTest("testMyJavaClass"))
>---- end example.py ----
>
>Running this from the command line I get:
>
>$ cmd /c c:/devel/jython-2.1/jython.bat example.py
>.F
>Time: 0
>There was 1 failure:
>1) testMyJavaClass(org.python.proxies.__main__$MyJavaClassTest$1) "Method "testM
>yJavaClass" not found"
>
>FAILURES!!!
>Tests run: 1,  Failures: 1,  Errors: 0
>
>As you can see the JUnit TestCase class is using reflection to look for the
>testMyJavaClass method. Will this example only work if I run jythonc?

Yes.

>It
>looks like the autogenerated proxy class is ignoring the "@sig"
>information.

Correct. This is unlikely to change.

>Also, with the upcoming 2.1 release, will function attributes be used to 
>replace the "@sig" syntax?

No.

You will have to override the runTest() method in order to subclass
TestCase:

import java, junit
class MyJavaClassTest(junit.framework.TestCase):
	def __init__(self, name):
		junit.framework.TestCase.__init__(self, name)
	def setUp(self):
		pass
	def runTest(self):
		self.testMyJavaClass()
	def testMyJavaClass(self):
		print "testing"

junit.textui.TestRunner.run(MyJavaClassTest("someName"))

regards,
finn