Setting the value of a global variable from a transformation

The following code sample shows how to prompt a user for a value, in the case the prompt is asking for a customer number, and then set the customerNumber global variable with this value.
Button button = new Button(this, SWT.NONE);
button.setText("Prompt for command");
button.addSelectionListener(new org.eclipse.swt.events.SelectionAdapter() {

public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
    InputDialog dialog = new InputDialog(getShell(), "Prompt", 
                                         "Enter a customer number:", "", null);
    if (dialog.open() == InputDialog.OK) {
        String value = dialog.getValue();
        getSessionService().getParameterDataAccessService().
                setParameterValue("hatsgv_customerNumber",value);
    }
}
 });
Note: The ZIETrans runtime is unaware of the new global variable value, set by the setParameterValue() method call, until the form is submitted.