OWGIS-created websites display layers that are served through
map servers. The information about each layer, such as the name of
the layer, is configured using XML files. These files are used to
modify the look and content of the OWGIS sites and are described
in Section 3. OWGIS monitors any changes to these files, made by
the administrators, and is able to update websites without
reloading the web application on the server. This feature is very
useful when the data being displayed on the map is modified often.
Fig. 2 shows a simple diagram of the process used by OWGIS to
generate web content for the user.
When a user makes a new HTML request, OWGIS verifies that
have been no modifications to the XML configuration files. If there
have been any changes, OWGIS parses all the information in the
XML files and rebuilds internal data structures for the sites. Once
the information is stored internally, OWGIS uses it to build the
desired interface, taking into account the specific user request.
The OWGIS source code is divided in four general modules:
model, business, servlets, and tools. The model module stores all
the layers obtained from the XML files as well as the menus in a set
of data structures. The servlets module contains all the servlets,
which are in charge of receiving new requests from the user and
redirecting each request to the proper method in the business
module. The servlets module also sends customized JavaScript code
to the user. The business module is in charge of reading the current
user's configuration and the data of the model module to build the
proper JavaScript code for the user. The tools module contains a
number of static functions used to create web content.