Information Technology Reference
In-Depth Information
Tabl e 1.
Core classes of Cloud Agency Client API
Class
Description
This abstract class represents an instance of the Cloud
Agency Client. Who wants to develop a new client for
the Cloud Agency has to extend it
CAClient
This class represents the established connection be-
tween the client and the Cloud Agency. It is in charge
of authenticating the user against the Cloud Agency
and of initializing instances of stubs and adapters
CAConnection
This abstract class implements a generic event listener.
It handles the generic asynchronous messages coming
from the Cloud Agency
CAEventListener
This class abstracts an asynchronous event received
from a listener
CAEvent
This interface represents the message parser used by
an event listener in order to process an asynchronous
message coming from the Cloud Agency and to gener-
ate a CAEvent
DefaultMessageParser This is the default implementation of a MessageParser
CAStub
MessageParser
This abstract class implements the generic stub
-
adapters
: an adapter is an handler for the asynchronous messages coming
from the Cloud Agency, according to its event-driven architecture. When
a new message arrives, it is forwarded to the adapter that implements the
particular service listener. Each user can customize the client behavior on the
arrival of particular events by simply extending the
CAEventListener
class or
overriding an existing adapter. So he/she can implement autonomic reactions
by adding his/her own new adapter by the core API. At the state-of-the-art
of the development of the API client there are four classes that implement
the
CAEventListener
class and that handle (without performing any action
outside of the displaying the received message) provisioning, management,
monitoring and reconfiguration events.
These APIs are also used to implement a command line and a graphical user
interface of a Cloud Agency console.
5.2 Command Line and Graphical User Interface
Cloud Agency
Command Line Interface (CA-CLI)
offers a variety of com-
mands to invoke the Cloud Agency's services. It follows the user in all the phases
of the deployment and of the execution of his/her own application by giving
him/her the possibility to book and manage the Cloud resources in a flexible
and simple way. The CA-CLI helps the mOSAIC developer in the deployment
process, beginning from the brokering of the best resources for his/her appli-
cation. The application opens a console that starts a listener to handle the
notifications sent by Cloud Agency and allows for the execution of a number
