Combining Information from Multiple Internet Sources

2.1 Design of the application part
The application part is written using the Java language and utilizes the agent platform – JADE
which is also written using Java. The web application hence it requires the Java Servlet Container –
for this purpose Apache-Tomcat was used.
To create the testing tools the JADE Agent platform was utilized. Agents provide us with an
abstract layer which can reflect the real-life situations. Agents play the role of experts at knowledge
about given queries by hiding from the user the presence of the real search engines. Though the
usage of software agents was not necessary it was an interesting and easy way to write an
application; even such one which is written only to aid in testing something different than a multiagent
system. Agents provide an easy interface of communication between objects and modules and
that makes developing applications relatively easy. Though there is a variety of agent platforms like
IBM Aglets or ZEUS the decision was made to use JADE since it is still actively developed whereas
other agent frameworks are not. Summarizing, the tool could be written without any agent platform,
but development of agent based environments is fairly easy and, at the same moment, very elegant.
Next part presents the detailed design of the application. In general the application can be
divided into two modules: Client and Main. The Client module is responsible for serving user
requests and forwarding those to the web part of the application. Client module is responsible for
interacting with the end-user; The Main module receives requests from the Client module and
manages necessary agents for information retrieval and processing of the retrieved results. The
Main module could also be accessed from any application (standalone/web based) as its entry point
is started as a separate thread in the application.
Next part of the chapter describes the Client module design details. Its information flow,
workflow and functionality will be described. Afterwards, in the next part of the chapter, in similar
manner, the Main module will be presented.
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