Cisco Cisco Customer Voice Portal 8.0(1) Developer's Guide
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would be handled in the same order they occurred within the call. To remedy this situation while
keeping the design unfettered, it is possible to specify that Unified CVP VoiceXML Server pass
a logger instance events in the same order they occurred in a call. With this option on, the logger
developer can be assured that the events for a call would not be handled out of order. In fact, the
Activity Logger included with the VoiceXML Server has this requirement. The penalty for this
requirement, however, is a loss of some of the true asynchronous nature of the system as there
will now be situations where events that are ready to be handled must wait for a previous event
to be handled by the logger. If a logger hung while handling one event, the queue would forever
contain the events that occurred after it in the call, and that call session would not be fully
logged.
keeping the design unfettered, it is possible to specify that Unified CVP VoiceXML Server pass
a logger instance events in the same order they occurred in a call. With this option on, the logger
developer can be assured that the events for a call would not be handled out of order. In fact, the
Activity Logger included with the VoiceXML Server has this requirement. The penalty for this
requirement, however, is a loss of some of the true asynchronous nature of the system as there
will now be situations where events that are ready to be handled must wait for a previous event
to be handled by the logger. If a logger hung while handling one event, the queue would forever
contain the events that occurred after it in the call, and that call session would not be fully
logged.
Some of the conclusions that can be deduced from the Unified CVP VoiceXML Server logging
design can be summarized in some best practices:
design can be summarized in some best practices:
A logger developer need not worry about the time taken by the logger to handle an event as it
will have no bearing on the performance of the call. With that said, the developer must also
be aware of the expected call volume and ensure that the logger not take so long as to use up
the event threads faster than they can be handled.
be aware of the expected call volume and ensure that the logger not take so long as to use up
the event threads faster than they can be handled.
Loggers work under a multi-threaded environment and the logger developer must understand
how to code with this in mind. A single logger class can be handling events for many calls
and so it must manage internal and external resources in a synchronized manner to prevent
non-deterministic behavior.
and so it must manage internal and external resources in a synchronized manner to prevent
non-deterministic behavior.
When possible, design the logger so that it does not rely on events within a call being passed
to it in the order in which they occurred in the call. Doing so will maximize performance due
to being able to handle events whenever they occur. Should the logger be unable to do so,
require that the enforce call event order option be turned on for the logger.
to being able to handle events whenever they occur. Should the logger be unable to do so,
require that the enforce call event order option be turned on for the logger.
Logger Design
Similar to configurable elements, a logger is constructed by creating a Java class that extends an
abstract base class,
abstract base class,
ApplicationLoggerBase
. The base class defines abstract methods that must
be implemented by the logger. A logger must implement a Java marker interface named
LoggerPlugin
to allow Unified CVP VoiceXML Studio to recognize it as a valid logger.
Loggers have methods for initialization and destruction as well as an execution method to call
when an event is to be handled. These methods may throw an
when an event is to be handled. These methods may throw an
EventException
to indicate an
error in the logger.
All Java classes related to loggers are found in the
com.audium.server.logger
package while
the logger event classes are found in the
com.audium.server.logger.events
package.
Logger Methods
void initialize(File configFile, LoggerApplicationAPI api)