Re: [Jython-users] Explicitly creating listeners from callables

[Samuele Pedroni <pedronis@bl...>]

Hi. Without messing with the internals one can do:

<adapter.py>
import new

_adapt_u=0

def adapt(listenerClass, **bindings):
   global _adapt_u
   _adapt_u +=1
   return new.classobj("_%s" % _adapt_u,( listenerClass,),bindings)()

</adapter.py>

then one can do:

>>> from javax.swing import JButton,JFrame
>>> f=JFrame("exp")
>>> from java.awt.event import ActionListener
>>> def doIt(self,e): print "ok!"
...
>>> from adapter import adapt
>>> b=JButton("Ok",actionListener=adapt(ActionListener,actionPerformed=doIt))
>>> f.contentPane.add(b)
[snipped output]
>>> f.pack()
>>> f.visible=1 # click on the button
>>> ok!

regards, Samuele Pedroni.

----- Original Message ----- 
From: Kevin Butler <kbutler@...>
To: Michael Haggerty <haggerty@...>
Cc: <jython-users@...>
Sent: Friday, January 18, 2002 10:34 PM
Subject: Re: [Jython-users] Explicitly creating listeners from callables


> Michael Haggerty wrote:
> >
> > Is there a way to access jython's "callable-to-listener" conversion
> > explicitly?  
> 
> You can (cheat a lot and) actually modify the JComboBox.__dict__:
> 
> """
> adapter.py - demo how to explicitly create an adapter for a Java interface.
> 
> This adds the capability to set 'actionPerformed=callable' in a JComboBox
> constructor.
> 
> Note that this hides the 'JComboBox.actionPerformed' method which
> caused the trouble in the first place, but you're not supposed to do
> anything with that method, so it is probably OK...
> 
> *WARNING* This is a hack - it works for Jython 2.1, but probably won't work
> with future releases.
> """
> from org.python.core import PyBeanEventProperty, PyBeanEvent
> 
> def addEventProperty( objectClass, addMethodName, eventName, eventClass ):
>     """Add the ability to call 'method=callable' in a constructor call.
>     objectClass   - class to modify
>     addMethodName - objectClass method to add a listener
>     eventName     - name of event listener property ('actionListener')
>     eventClass    - class of event listener interface
>     """
>     # code stolen from PyJavaClass.addEvent
>     addMethod = objectClass.getMethod( addMethodName, [eventClass] )
> 
>     # add support for assigning individual event handlers in constructor
>     for eventMethod in eventClass.getMethods():
>         prop = PyBeanEventProperty(
>             eventName,
>             eventClass,
>             addMethod,
>             eventMethod
>             )
>         objectClass.__dict__.__setitem__( prop.__name__, prop )
> 
>     # add support for assigning 'whateverListener=WhateverListenerImpl'
>     event = PyBeanEvent(eventName, eventClass, addMethod);
>     objectClass.__dict__.__setitem__(event.__name__, event);
> 
> 
> 
> # demo code
> from javax.swing import JComboBox, JFrame
> from java.awt.event import ActionListener
> from java.awt import Dimension, BorderLayout
> def showWidget( widget, name="Demo" ):
>         f = JFrame( name )
>         p = f.getContentPane()
>         p.add( widget, BorderLayout.NORTH )
>         f.setSize( 300, 300 )
>         f.show()
> 
> 
> def test():
>     # allow JComboBox( actionPerformed=callable )
>     addEventProperty(
>         JComboBox,
>         'addActionListener',
>         'actionListener',
>         ActionListener
>         )
> 
>     def doit( event ):
>         print "doit:", event
> 
>     jc = JComboBox( range( 10 ), actionPerformed=doit )
>     showWidget( jc )
> 
> 
> 
> Cool.  :-)
> 
> kb
> 
> _______________________________________________
> Jython-users mailing list
> Jython-users@...
> https://lists.sourceforge.net/lists/listinfo/jython-users
> 

Re: [Jython-users] Explicitly creating listeners from callables

[Kevin Butler <kbutler@ca...>]

Michael Haggerty wrote:
>
> Is there a way to access jython's "callable-to-listener" conversion
> explicitly?  

You can (cheat a lot and) actually modify the JComboBox.__dict__:

"""
adapter.py - demo how to explicitly create an adapter for a Java interface.

This adds the capability to set 'actionPerformed=callable' in a JComboBox
constructor.

Note that this hides the 'JComboBox.actionPerformed' method which
caused the trouble in the first place, but you're not supposed to do
anything with that method, so it is probably OK...

*WARNING* This is a hack - it works for Jython 2.1, but probably won't work
with future releases.
"""
from org.python.core import PyBeanEventProperty, PyBeanEvent

def addEventProperty( objectClass, addMethodName, eventName, eventClass ):
    """Add the ability to call 'method=callable' in a constructor call.
    objectClass   - class to modify
    addMethodName - objectClass method to add a listener
    eventName     - name of event listener property ('actionListener')
    eventClass    - class of event listener interface
    """
    # code stolen from PyJavaClass.addEvent
    addMethod = objectClass.getMethod( addMethodName, [eventClass] )

    # add support for assigning individual event handlers in constructor
    for eventMethod in eventClass.getMethods():
        prop = PyBeanEventProperty(
            eventName,
            eventClass,
            addMethod,
            eventMethod
            )
        objectClass.__dict__.__setitem__( prop.__name__, prop )

    # add support for assigning 'whateverListener=WhateverListenerImpl'
    event = PyBeanEvent(eventName, eventClass, addMethod);
    objectClass.__dict__.__setitem__(event.__name__, event);



# demo code
from javax.swing import JComboBox, JFrame
from java.awt.event import ActionListener
from java.awt import Dimension, BorderLayout
def showWidget( widget, name="Demo" ):
        f = JFrame( name )
        p = f.getContentPane()
        p.add( widget, BorderLayout.NORTH )
        f.setSize( 300, 300 )
        f.show()


def test():
    # allow JComboBox( actionPerformed=callable )
    addEventProperty(
        JComboBox,
        'addActionListener',
        'actionListener',
        ActionListener
        )

    def doit( event ):
        print "doit:", event

    jc = JComboBox( range( 10 ), actionPerformed=doit )
    showWidget( jc )



Cool.  :-)

kb

RE: [Jython-users] IOError differences

[brian zimmer <bzimmer@zi...>]

Tom,

Unfortunately in Jython 2.1 none of the socket method calls throw
exceptions as documented.  The underlying Java exception is thrown, not
the tuple as httplib expects.  Another problem is the lack of an errno
module.  I am actively working on this in the hopes of getting Jython
2.2 compliant.  I, like you, want this to work in Jython properly.  In
the interim I don't know of a solution.

thanks,

brian

> -----Original Message-----
> From: jython-users-admin@... 
> [mailto:jython-users-admin@...] On Behalf 
> Of Russo, Tom
> Sent: Friday, January 18, 2002 2:46 PM
> To: 'jython-users@...'
> Subject: [Jython-users] IOError differences
> 
> 
> http://www.jython.org/docs/differences.html says:
> "Jython uses different values for the IOError argument. This 
> causes trouble
> for people who unpack the value into an (errno, message) tuple."
> 
> Is there any more documentation on these differences?  I'm getting an
> attribute error for __getitem__ in httplib.py:
> 
>         except socket.error, v:
>             # trap 'Broken pipe' if we're allowed to 
> automatically reconnect
>             if v[0] != 32 or not self.auto_open:              
>  # <--- the
> error happens here (at v[0])
>                 raise
> 
> and I'd like to correct it.
> 
> thanks
> _t
> 
> _______________________________________________
> Jython-users mailing list
> Jython-users@...
> https://lists.sourceforge.net/lists/listinfo/jython-users
> 

[Jython-users] IOError differences

[Russo, Tom <tom@st...>]

http://www.jython.org/docs/differences.html says:
"Jython uses different values for the IOError argument. This causes trouble
for people who unpack the value into an (errno, message) tuple."

Is there any more documentation on these differences?  I'm getting an
attribute error for __getitem__ in httplib.py:

        except socket.error, v:
            # trap 'Broken pipe' if we're allowed to automatically reconnect
            if v[0] != 32 or not self.auto_open:               # <--- the
error happens here (at v[0])
                raise

and I'd like to correct it.

thanks
_t

[Jython-users] Re: [Jython-dev] Another new Jython book

[<bckfnn@wo...>]

[Noel Rappin]

>Finn, could you also add the information for _Jython Essentials_ from 
>O'Reilly, by me and Samuele?  We just popped up on the O'Reilly web site, 
>and on Amazon.  The book is due out in March.
>
>http://www.oreilly.com/catalog/jythoness/

I would rather wait until the book is shipping. While I'm very grateful
for the great work you and other book authors have done, I feel that the
front page should be reserved for facts and not for marketing.

OTOH, you and all other jython book and jython software authors are more
than welcome to announce your work on jython-announce and on the other
jython lists.

I hope you can understand my position on this. For the jython software
itself, we would never announce a release before it is available. Don't
hesitate to prod me again when your book is released.

regards,
finn

[Jython-users] Calling overloaded methods of a java-subclass within python?

[Martin <m.moebius@gm...>]

hi,

i pass a java-object to very simple python-script. The scripts manipulate
this object.
Now i had to extend this java-object, and i handle this objects in other
python scripts, but further passing the object as the superclass.
In the extended Class i added 2 Methodes and overloaded another one.
Now i get 
TypeError:
- args; got 5 update(): expected 1 or 4

update() is the overload  method, wich have now 5 parameter.
The strange thing is the other two methods are called correct.

def do_stuff():
    global java_object
    # getSpecialValue1() &2 are declared in the subclass of java_object,
that works !
    value1=java_object.specialValue1
    value2=java_object.specialValue2
    value3=java_object.value1
    #update(double,double,double,double,double) is overloaded from
Java_Object
    # that fails 
    java_object.update(value1,value2,value3,value2+value1,value2-value3)

Just a sketch of the classes and methods:

class Java_Object{
 public double getValue1(){return -1;}
 public double getValue2(){return -1;}
 public void (Object o)
 public void update(double a, double b, double c, double d){//do stuff}
}

class Java_Object2 extends Java_Object{
 //new method
 public double getSpecialValue1(){return -1;}
 //new method
 public double getSpecialValue1(){return -1;}
 // 5 parameter instead 4
 public void update(double a, double b, double c, double d, double z){//do
stuff}
}

//main point für script processing
public void invokeScript(String function, Java_Object java_object){
 pythonInterpreter.set("java_object",java_object)
 pythonInterpreter.exec(function) 
}

I've read that jython get confused with different method signatures, but
only examples how to call methods of the super class, i want to call a method of
a subclass.
In java i would cast java_object to Java_Object2, but python have no concept
of casting(AFAIK). So what can i do?

any help, or pointers to documention & examples are very appreciated. 

-- 

Martin Möbius

Re: [Jython-users] java 2 and com on mswindows platforms

[Syver Enstad <syver-en@on...>]

Dana.Moore@... writes:

> Syver,
> thanks for your contribution. It looks really clean and 
> lovely, and  with your permission, I would like to use 
> it as part of the talk ("Scripting Java") I am giving at 
> JavaOne in March. 

Wow, that's flattery, (blush). You (and everybody else) are of course
permitted to do whatever you like with the code. 

If you are interested, I have made some subclasses of the classes I
sent you, that instead of using the jawin COM bridge, uses the jacob
com bridge instead. In my experience jawin and jacob seems to be very
similar. They both use JNI to access the native COM library, and the
api they present are quite similar. Both projects are also open source
and with no painful restrictions for use as far as I have seen.

Both jawin and jacob have associated code generators for generating
java wrapper code to make using COM from java more like using "real"
java objects, but these tools at least for jawin, seems to be a bit
alpha for the time being. When I tried it, there were some methods
that the generator didn't create and so on.

The code generator shouldn't be that necessary in jython, because as I
have shown in the jythoncom.py file, we can present a pythonic
interface by doing tricks with __getattr__ and friends. One thing
might be problematic and that is byref/out parameters, which should be
translated to multiple returnvalues in python. pythoncom/win32com for
cpython is able to handle this when using generated wrappers, but it
is a problem for the dynamic version of the com support (ie. similar
to the jythoncom module)

It would probably be a good thing to make some base class that are
independent of the underlying COM bridge, put the various
implementations in their own module, at least when the implementation
has stabilized a bit. 

Maybe like this?
import jythoncom.jawin
or
import jythoncom.jacob




-- 

Vennlig hilsen 

Syver Enstad

Re: [Jython-users] stupid newbie question

[Samuele Pedroni <pedronis@bl...>]

From: Steve Cohen <SteveC@...>
> There is some meat on this stupid newbie question, isn't there? 8-)
> 
> I just typed return.

mumble.

> 
> This was on a RedHat linux installation with the revisions to
> ReadlineConsole.java that I submitted last week and the installation was
> set to use org.gnu.Readline
> 

This could play some role. And I should admint I have never tried it myself.
So can you try the following snippet:

>>> if 1:
...  print "hello"
   ^here goes a space
...
   ^ just return or space plus just return :)
hello

Does it work for you?

PS:
> stupid newbie questionPuzzled me.
This was not voluntary. It is indeed the funny result
of some rushed editing :).

R: [Jython-users] JIT under jython, how to enable

[Samuele Pedroni <pedronis@bl...>]

From: Syver Enstad <syver-en@...>
> "Samuele Pedroni" <pedronis@...> writes:
> 
> > What JVM are you using? 
> 
> Thanks Samule, I am indeed using the Sun Java 2 Hot Spot. Thanks for
> explaining why JIT is not an option for that VM.

You're welcome. Btw you can turn it off, the adaptive compiler,
 and some debugging option do that, but it never shows out as a JIT.

Samuele.

Re: [Jython-users] JIT under jython, how to enable

[Syver Enstad <syver-en@on...>]

"Samuele Pedroni" <pedronis@...> writes:

> What JVM are you using? 

Thanks Samule, I am indeed using the Sun Java 2 Hot Spot. Thanks for
explaining why JIT is not an option for that VM.


-- 

Vennlig hilsen 

Syver Enstad

RE: [Jython-users] stupid newbie question

[Steve Cohen <SteveC@ig...>]

There is some meat on this stupid newbie question, isn't there? 8-)

I just typed return.

This was on a RedHat linux installation with the revisions to
ReadlineConsole.java that I submitted last week and the installation was
set to use org.gnu.Readline

-----Original Message-----
From: Samuele Pedroni [mailto:pedronis@...]
Sent: Friday, January 18, 2002 10:45 AM
To: jython-users@...; Steve Cohen
Subject: Re: [Jython-users] stupid newbie question


stupid newbie questionPuzzled me.

[Steve Cohen session]
=A6>>> if entries.hasMoreElements():
=A6...   print "hello"
=A6...
=A6Traceback (innermost last):
=A6  (no code object) at line 0
=A6  File "<console>", line 3
=A6        null
=A6        ^
=A6SyntaxError: invalid syntax
=A6>>>

If it says it's a syntax error it is one (with very high probability).
What do you typed on the second "..." line, I really mean what keyboard
char?
I'm unable to find a key combination that produces the
signaled empty (null) line.

Thanks, Samuele Pedroni.

Re: [Jython-users] stupid newbie question

[Samuele Pedroni <pedronis@bl...>]

stupid newbie questionPuzzled me.

[Steve Cohen session]
=A6>>> if entries.hasMoreElements():
=A6...   print "hello"
=A6...
=A6Traceback (innermost last):
=A6  (no code object) at line 0
=A6  File "<console>", line 3
=A6        null
=A6        ^
=A6SyntaxError: invalid syntax
=A6>>>

If it says it's a syntax error it is one (with very high probability).
What do you typed on the second "..." line, I really mean what keyboard c=
har?
I'm unable to find a key combination that produces the
signaled empty (null) line.

Thanks, Samuele Pedroni.

Re: [Jython-users] Not-so-stupid question

[Samuele Pedroni <pedronis@bl...>]

[Eric E. Allen]
> The Enumeration interface includes a hasMoreElements() method, but not a
> hasNextElement().
>  As to why hasNext() works: my guess is that the
> implementation of Enumeration returned by the Hashtable also supports the
> (preferred) Iterator interface.
>

This is also true at least with sun jdk, (one can check the source of the
library classes :)).

The point here to note is that jython give you access to all the methods of the
concrete class of a Java object (inclusive all superclasses methods),
it is not that in case a Java method returns an Enumeration on Jython side
the returned object will offer that limited view of its concrete behavior.

regards, Samuele Pedroni.

[Jython-users] Another new Jython book

[Noel Rappin <noelrap@ya...>]

>
> >would you please put in the 'Jython News' resp. 'Jython In
> >the press' part of the home page the hint for the new jython book:
> >http://newriders.com/books/title.cfm?isbn=0735711119

Finn, could you also add the information for _Jython Essentials_ from 
O'Reilly, by me and Samuele?  We just popped up on the O'Reilly web site, 
and on Amazon.  The book is due out in March.

http://www.oreilly.com/catalog/jythoness/

Thanks,

Noel Rappin


_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com

Re: [Jython-users] Not-so-stupid question

[Eric E. Allen <eallen@cs...>]

The Enumeration interface includes a hasMoreElements() method, but not a
hasNextElement(). As to why hasNext() works: my guess is that the
implementation of Enumeration returned by the Hashtable also supports the
(preferred) Iterator interface.

-- Eric



On Fri, 18 Jan 2002, Steve Cohen wrote:

> All right, here is a distillation of what I thought was a stupid newbie
> question last night, but now I'm genuinely puzzled:
>
> >>> from java.util import Hashtable
> >>> h=Hashtable()
> >>> h
> {}
> >>> h.put("2","3")
> >>> h.put("1","2")
> >>> h
> {2=3, 1=2}
> >>> e=h.elements()
> >>> e
> java.util.Hashtable$Enumerator@...
> >>> e.hasNextElement()
> Traceback (innermost last):
>   File "<console>", line 1, in ?
> AttributeError: hasNextElement
> >>> e.hasNext()
> 1
> >>> e.nextElement()
> '3'
> >>> e.nextElement()
> '2'
> >>>
>
> h.elements returns a java.util.Enumeration
> That interface has hasNextElement() and nextElement() methods.  It does
> not have a hasNext() method. Yet under jython, hasNextElement() is not
> recognized while hasNext() is recognized.
>
> What is going on here?
>
> _______________________________________________
> Jython-users mailing list
> Jython-users@...
> https://lists.sourceforge.net/lists/listinfo/jython-users
>

[Jython-users] Not-so-stupid question

[Steve Cohen <SteveC@ig...>]

All right, here is a distillation of what I thought was a stupid newbie
question last night, but now I'm genuinely puzzled:

>>> from java.util import Hashtable
>>> h=3DHashtable()
>>> h
{}
>>> h.put("2","3")
>>> h.put("1","2")
>>> h
{2=3D3, 1=3D2}
>>> e=3Dh.elements()
>>> e
java.util.Hashtable$Enumerator@...
>>> e.hasNextElement()
Traceback (innermost last):
  File "<console>", line 1, in ?
AttributeError: hasNextElement
>>> e.hasNext()
1
>>> e.nextElement()
'3'
>>> e.nextElement()
'2'
>>>

h.elements returns a java.util.Enumeration
That interface has hasNextElement() and nextElement() methods.  It does
not have a hasNext() method. Yet under jython, hasNextElement() is not
recognized while hasNext() is recognized.

What is going on here?

[Jython-users] Explicitly creating listeners from callables

[Michael Haggerty <haggerty@jp...>]

Hello,

Is there a way to access jython's "callable-to-listener" conversion
explicitly?

I would like to do this:

class C:
    def __init__(self):
        # ...
        b = JComboBox(actionPerformed=self.doIt)
        # ...

    def doIt(self, e):
        # ...

but it doesn't work because JComboBox (oddly) defines an
actionPerformed method.  (See

    http://aspn.activestate.com/ASPN/Mail/Message/Jython-users/541301

for more information.)

Is there a way to access jython's "callable-to-listener" conversion
explicitly?  If so, I could do

    b = JComboBox(actionListener=jython_coersion(actionPerformed=self.doIt))

which is not quite as terse as the original, but at least better than
having to define a python wrapper class to do the trick (and probably
a bit faster, too).  Ideally this would be spelled

    b = JComboBox(actionListener=ActionListener(actionPerformed=self.doIt))

but unfortunately this produces an error

    TypeError: can't instantiate interface (java.awt.event.ActionListener)

Thanks,
Michael

-- 
Michael Haggerty
JPK Instruments
haggerty@...

Re: [Jython-users] JIT under jython, how to enable

[Samuele Pedroni <pedronis@bl...>]

Hi.

What JVM are you using? The Sun JVM
post 1.2 uses the HotSpot JVM,
which does adaptive native compiling,
but does not declare itself with a JIT,
because differently from the previous
generation of JIT its activitity is mostly
transparent. You should see something like:

>java -version
java version "1.3.0_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0_01)
Java HotSpot(TM) Client VM (build 1.3.0_01, mixed mode)

Btw, mixed mode means: interpretation plus adaptive 
native compilation of "hotspots".

What is true is that the HotSpot JVM
has a client and server version,
AFAIK there is no server version
from sun for Linux. Both versions
do native compilation but with
different trade-offs wrt maximum
optimization and interactive response.

regards, Samuele Pedroni.

----- Original Message ----- 
From: Syver Enstad <syver-en@...>
To: <jython-users@...>
Sent: Friday, January 18, 2002 6:23 AM
Subject: [Jython-users] JIT under jython, how to enable


> 
> I've tried setting the option in the registry to true, but jython
> still says JIT: null when I am starting it.
> 
> -- 
> 
> Vennlig hilsen 
> 
> Syver Enstad
> 
> 
> 
> _______________________________________________
> Jython-users mailing list
> Jython-users@...
> https://lists.sourceforge.net/lists/listinfo/jython-users
> 

Re: [Jython-users] JIT under jython, how to enable

[Brian Takashi Hooper <brian@ji...>]

Under Linux, I think the OpenJIT is a good choice for a JIT, see the
following URL:

http://www.openjit.org/

I haven't tried using it with Jython yet, however.

-Brian

----- Original Message -----
From: "dman" <dsh8290@...>
To: <jython-users@...>
Sent: Friday, January 18, 2002 3:47 PM
Subject: Re: [Jython-users] JIT under jython, how to enable


> On Fri, Jan 18, 2002 at 06:23:45AM +0100, Syver Enstad wrote:
>
> | I've tried setting the option in the registry to true, but jython
> | still says JIT: null when I am starting it.
>
> There is no JIT in jython; the JIT is a java thing.  Which JVM and
> which platform are you on?  I don't think linux has a JIT since I
> never see it enabled on my system, but I did see it enabled on
> windows.
>
> -D
>
> --
>
> The fear of the Lord leads to life:
> Then one rests content, untouched by trouble.
>         Proverbs 19:23
>
>
> _______________________________________________
> Jython-users mailing list
> Jython-users@...
> https://lists.sourceforge.net/lists/listinfo/jython-users
>

Re: [Jython-users] JIT under jython, how to enable

[dman <dsh8290@ri...>]

On Fri, Jan 18, 2002 at 06:23:45AM +0100, Syver Enstad wrote:
 
| I've tried setting the option in the registry to true, but jython
| still says JIT: null when I am starting it.

There is no JIT in jython; the JIT is a java thing.  Which JVM and
which platform are you on?  I don't think linux has a JIT since I
never see it enabled on my system, but I did see it enabled on
windows.

-D

-- 

The fear of the Lord leads to life:
Then one rests content, untouched by trouble.
        Proverbs 19:23

[Jython-users] JIT under jython, how to enable

[Syver Enstad <syver-en@on...>]

I've tried setting the option in the registry to true, but jython
still says JIT: null when I am starting it.

-- 

Vennlig hilsen 

Syver Enstad

Re: [Jython-users] java 2 and com on mswindows platforms

[Syver Enstad <syver-en@on...>]

[Jython-users] stupid newbie question

[Steve Cohen <SteveC@ig...>]

jython and ZipFile and Enumeration - what's happening here?


[scohen@... scohen]$ jython
Jython 2.1 on java1.3.0 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> from java.util.zip import ZipFile, ZipEntry
>>> zf =3D ZipFile("jython.jar")
>>> entries =3D zf.entries()
>>> entries
java.util.zip.ZipFile$2@...
>>> entries.hasMoreElements()
1
>>> entries.nextElement()
META-INF/
>>> entries.nextElement()
META-INF/MANIFEST.MF
>>> entries.nextElement()
com/
>>> entries.nextElement()
com/ziclix/
>>> entries.hasMoreElements()
1
>>> if entries.hasMoreElements():
...   print "hello"
...=20
Traceback (innermost last):
  (no code object) at line 0
  File "<console>", line 3
	null
	^
SyntaxError: invalid syntax
>>>=20
entries.hasMoreElements() returns 1 but if I use it in an expression I
get this error.  What's going on here?