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

[Kevin B. <kb...@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