[Asterisk-java-users] Support for EventGeneratingActions in Asterisk-Java CVS-HEAD

[Stefan R. <sr...@re...>]

Hi,

I just finished to implement support for what I call
EventGeneratingActions in Asterisk-Java.
Let me explain what that means.

The problem:

An increasing number of Actions in Asterisk's Manager API doesn't send
their result in the Response but generate a series of Events that
contain the payload.
An old example of this is the StatusAction. It sends a Response
indicating success and a StatusEvent for each active channel and finally
a StatusCompleteEvent to indicate that all StatusEvents have been sent.
This concept is also used in newer Actions in Asterisk CVS-HEAD like the
AgentsAction or the DBGetAction.
The concept is always the same:
=3D> send action
<=3D receive response (only indicating success)
<=3D receive events
<=3D receive action complete event
The Events are linked to the Action that generated them by a common
actionId attribute.
The problem is that when using Asterisk-Java processing these Actions
has been a nightmare. You had to register an event handler, send the
Action and instruct the event handler to collect the corresponding
events and finally put them together.
An example of this nightmare is the initialize phase in
DefaultAsteriskManager in Asterisk-Java 0.1.

The solution:

Now Asterisk-Java provides support for EventGeneratingActions at
ManagerConnection level. There is a new EventGeneratingAction interface
that is implemented by all ManagerAction classes that result in events
being sent. It extends the ManagerAction interface by a method called
getActionCompleteEventClass() that returns the class of the event that
indicates completion. The ManagerConnection interface now includes two
synchronous sendEventGeneratingAction() methods that return the Response
and all Events that have been received in response to the Action.

If you are interested have a look at the latest snapshot of
Asterisk-Java available at=20
http://maven.reucon.com/maven/asterisk-java/distributions/
or browse the updated Asterisk-Java sources at
http://asterisk-java.sourceforge.net/xref/index.html

The latest implementation of DefaultAsteriskManager already uses this
new feature of ManagerConnection and is much cleaner now.
A little hack (see EventTimeoutException in net.sf.asterisk.manager if
you are interested) also solves the queue initialization problem in
DefaultAsteriskManager with buggy (i.e. current stable) Asterisk
servers.

=3DStefan