Developer's Guide

CHAPTER 9: CONFIGURABLE ELEMENTS VOICEXML PROGRAMMING GUIDE
FOR CISCO UNIFIED CUSTOMER VOICE PORTAL RELEASE 4.0(1)
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com.audium.server.voiceElement package. These three base classes all extend a common
base class for configurable elements, ElementBase.
In order for Unified CVP VoiceXML Studio to identify the Java class representing the actual
element (as opposed to another class lower in the class hierarchy or a standard element that also
extends that class), a “marker” Java interface named
ElementInterface must be implemented.
Only those classes that implement this interface are shown in VoiceXML Studio’s Element Pane.
Each configurable element contains a single execution method in which the element performs its
function. This method is called by Unified CVP VoiceXML Server when that element is visited
in the call flow. One can equate this method to the element’s
main() method, it begins and ends
there.
One argument to the method is an instance of a Session API class. Aside from the standard
functionality available in this class such as obtaining the ANI and setting element data, this API
class can be used to obtain a Java object representing the element’s configuration. The
VoiceXML Server automatically creates this configuration object with the data entered by the
application developer in VoiceXML Studio or made available through a dynamic configuration.
The name of the execution method and the API class passed to it differ for each element type as
do the classes encapsulating the element’s configuration. The execution method for decision and
voice elements must return an exit state and the execution method for action elements do not
return anything (since all action elements explicitly have a single exit state).
The execution method for action and decision elements can throw an AudiumException while
voice elements can throw an ElementException. The developer would throw this exception if
an error was encountered within the execution method that the developer wishes to end the call.
A call that encountered this exception would then visit the error element (or the application-
specific error message if the error element was not defined), and the error message is placed in
the error log including the exception’s full stack trace.
The base class also includes various methods used to define the element’s configuration. These
methods define everything from the element’s name to its possible exit states. These methods are
essential for Unified CVP VoiceXML Studio to visually render the element and its configuration
correctly. Custom elements will be indistinguishable from Unified CVP Elements within
VoiceXML Studio. The developer can choose as simple or complex a configuration as desired
(or even no configuration at all, though it wouldn’t be very reusable).
Note that element data generated by an element will be overwritten if that same element is
visited again in the call flow. For example, a variable set by a voice element handling the main
menu of an application will be reset the next time the main menu is visited. The activity log,
however, is a historical account of the call, so would have all values of the element data. Should
the developer wish to retain all data created by all visits to the element, they must build that into
the element, such as creating new variables or appending the new value to an existing variable.