Loading classes (Java)

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Due to Java’s class loader system loading a class to make it accessible to the test scripts is not always trivial.

Here is a helper function (loadClass()) that tries to cover all possible cases.

def main():
    startApplication("myaut")



    ### LOADING THE CLASS:

    ### Approach #1
    # Trying to load without GUI object class loader:
    loadClass("com.mine.TheClass")

    ### Approach #2
    # Trying to load without a GUI object class loader,
    # but silently (no failure log entries):
    loadClass("com.mine.TheClass", verbose=False)

    ### Approach #3
    # Trying to load via GUI object class loader; for GUI
    # classes which are not part of standard Java (meaning
    # anything that sub-classes AWT or Swing classes, and
    # classes that are not part of standard Java, like all
    # of SWT):
    gui_object = waitForObject("non_standard_java_gui_object")
    loadClass("com.mine.TheClass", gui_object)



    ### ACCESSING/USING THE CLASS:

    ### #1: Static methods
    # Invoking a static method of the class:
    something = com_mine.TheClass.getSomething()

    ### #2: Instance methods
    # Invoking a method of the instance (instantiate
    # the class first):
    theClassInstance = com_mine.TheClass()
    somethingElse = theClassInstance.getSomethingElse()



def loadClass(class_name, gui_object=None, verbose=True):
    # Try to load via GUI object's class loader:
    if gui_object is not None:
        cl = gui_object.getClass().getClassLoader()
        if not isNull(cl):
            try:
                return cl.loadClass(class_name);
            except:
                if verbose:
                    test.warning("Loading class via GUI object class loader unsuccessful: %s" % class_name)
        else:
            if verbose:
                test.warning("GUI object class loader is null (is the class of the GUI object part of standard Java perhaps?): %s" % class_name)

    # Try to load via current context class loader:
    try:
        # Class.forName uses the current context classloader and if
        # that is the boot classloader, apparently only classes from
        # rt.jar can be loaded
        return gui_object.getClass().forName(class_name)
    except:
        if verbose:
            test.warning("Loading class via current context class loader unsuccessful: %s" % class_name)

    # Try to load via system class laoder
    cl = java_lang_ClassLoader.getSystemClassLoader()
    try:
        return cl.loadClass(class_name)
    except:
        if verbose:
            test.warning("Loading class via system class loader unsuccessful: %s" % class_name)
    return None
test.py