Daffodil:System Description
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The Daffodil Agent Architecture
In this section we will describe the current system architecture of Daffodil.
A current overview is given by the following picture.
The Backend
The backend of the Daffodil Architecture (blue frame) is based on an CORBA agent architecture. Currently Daffodil consists of 35 different agents, plus additional software like a mysql database, the CORBA nameserver and a WEBDAV server. Within Daffodil are two different kind of agents, namely the Internal Agents and the External Agents. The first kind uses the CORBA communication and the later one a HTTP based communication.
CORBA Library
Daffodil is based on a jacorb CORBA version 1.3, which is pretty old, but works very well. The agents communicate via XML messages in an CORBA based environment, based on KQML. The underlaying CORBA library was provided by Multimedia Schemas with Semantic and Security Constraints, University of Dortmund.
WebDav
The WebDav Server is based on the libdav library. We have to change that sometime to the new apache WebDav library.
The Wrapper
The wrapper are one of the bases of Daffodil, since they enable access to all data-source. This is done through the WrapperToolkit.
External Agents
The Userinterface
The Dispatcher based communication hides coupling and network protocol details from the communicating parties. Each GUI component needs only to send messages via the dispatcher instance and receive answers from there.
