Cisco Cisco Unified Customer Voice Portal 11.0(1) Developer's Guide

PPENDIX

OICE

OUNDATION

LASSES

ISCO

CVP V

OICE

XML 3.1

Programmer

Guide

The following Java code demonstrates the concepts described above:

VPreference pref = ved.getPreference();
VForm form = VForm.getNew(pref, "start");

Here, the

VPreference

object is obtained from the

VoiceElementData

object passed as input to

a voice element. It is used to create a

VForm

object. Assuming the application is using the voice

browser Foo, that choice is reflected in the

VPreference

object and therefore the

getNew

factory

method returns a

VFormFoo

object, which is automatically downcasted to a

VForm

object. The

developer then uses the form object as desired.

This ability to treat all objects returned as a root VFC object is not available when the developer
wishes to use functionality that exists either in a particular version of VoiceXML or a particular
voice browser. The developer must understand that doing so would prevent their code from
functioning on all voice browsers. In this case, the developer simply treats the return of the
factory method as a class higher in the class hierarchy (

VFormV2

VFormFoo

in the example in

Figure 12-1).

The following Java code demonstrates this:

VGrammar myGrammar = VGrammar.getNew(pref);
((VGrammarV2) myGrammar).setMaxage(1000);

The

setMaxage

method exists only in the

VGrammarV2

class since this is a feature that exists only

in VoiceXML 2.0. To call this method, one must first upcast the previously downcasted object
back to

VGrammarV2

. If this is not done, an exception will be thrown indicating that

VGrammar

does not have a method named

setMaxage

. Also note that if the user in Studio chose a voice

browser that was compatible with VoiceXML 1.0 only, a runtime exception would be thrown
when this code is encountered because that browser would be unable to understand VoiceXML
referring to maxage.

VFC Classes

The following lists all the VFC classes (with full package names) and briefly explains what they
are responsible for. The Javadocs for the VFCs provide significantly more detail about the
classes, their methods, and how they are used.

•

com.audium.core.vfc.util.VMain.

This object is the container for a complete VoiceXML

document. It includes methods for managing information about the page such as the meta
tags, the doc type, and the value to put in the

<vxml>

tag’s

xml:lang

attribute. It includes

methods for adding document-scope data such as links, variables, and VoiceXML properties.

VForm

objects are added to this object to create the VoiceXML page. CVP VoiceXML Server

uses the

VMain

object to handle the printing of the VoiceXML page. Voice elements receive

an instantiated

VMain

object as input and the developer need only worry about filling the

object with the appropriate content.