Information Technology Reference
In-Depth Information
The modular design of our message translator (depicted in Figure 1) makes it
possible to extend the WebGateway-agent with any kind of content language.
Listing 1 and Listing 2 illustrate the content translation from a JSON-encoded
to an SL-encoded message.
{
”frame”: ”web
−
event
−
action”,
”events”: [
{
(
web
−
event
−
action
: events (sequence
(
”frame”: ”web
−
event”,
”event
−
id”: ”id1”,
”value”: ”button click”
web
−
event
:event
−
id id1
:data button click
}
)
]
)
}
)
Listing 1.
JSON
Listing 2.
Semantic Language
3
Related Work
In the area of multi-agent systems, the field of Web service integration into
multi-agent systems is well researched and yields in many interesting solutions.
The work reported in this paper is therefore influenced by several directions
but primarily inspired by the architectural design described in the publication
of D. Greenwood et al. [4]. Their approach provides a intermediary processor
called
Web Service Integration Gateway Service
(WSIGS) that is positioned on
the communication path between the service participants. It is implemented
as a JADE platform service and is accessible to internal platform agents and
external Web services. A different solution with almost the same functional-
ity was introduced by M. O. Shafiq et al. [11]. The authors interconnect both
technologies, FIPA multi-agent systems and Web services, with the help of a
middleware called
AgentWeb Gateway
, that provides appropriate transforma-
tion mechanisms to translate communication protocols and service description
languages. The
WS2JADE
Approach from X. T. Nguyen et al. [6] is based on a
two layer architecture. (1) The interconnection layer contains dynamic entities
called
WSAG
(Web Service Agents), which are capable of communicating with
and offering Web services as their own agent services. (2) The static manage-
ment layer is responsible for active service discovery and registration. It also
provides a deployment process that generates WSAGs and ontology mappings
at runtime. A common feature of all these approaches is that they assume and
are based on Web services that use the standard WSU
9
stack, i.e. they use an
XML based communication language (SOAP) and service description language
(WSDL). Another well established Web service implementation is the RESTful
architecture [10]. It increasingly gained popularity because of its simplicity in
terms of implementation and resource addressing. An approach which takes ad-
vantage of these features is proposed of E. L. Soto [5]. He implemented a
Web
Service Message Transport Service
(WSMTS) for JADE platforms that is capa-
ble of handling FIPA-SL messages in XML representation. The open language
9
WSDL, SOAP, UDDI (WSU).
