
Jeeves Core Servlets
The Jeeves servlet architecture is very flexible, and the server takes
advantage of this by dividing up its work among several core servlets.
File Servlet
The File servlet provides the standard document serving capabilites of Jeeves.
This servlet includes a caching mechanism to speed up response times for
frequently accessed files. In addition, it recognizes files that are
to be parsed for server side includes and passes them on to the SSInclude
Servlet.
Invoker Servlet
The purpose of this servlet is to invoke other servlets which are explicitly
requested by name, i.e.
http://<server-host-name>/servlet/<servlet-name>
.
SSInclude Servlet
This servlet parses server side include files (files with a .html
extension), and invokes any servlets referenced in the HTML. The results
returned from the servlets are embedded into the HTML file, which is then
returned to the requestor.
The HTML syntax for the embedded servlet tag is:
<SERVLET CODE="MyPackage.MyServletClass" NAME_1="VALUE_1" ... NAME_N="VALUE_N">
where NAME_1
through NAME_N
are the names of any
parameters you would like to send to the servlet, and VALUE_1
through VALUE_N are the values for those parameters. These parameters are
passed to the servlet in a hashtable.
Any servlet which services server side includes must implement the
sun.server.http.Filter
interface, which defines a single
method:
public void service(InputStream in, OutputStream out, Hashtable params)
throws java.io.IOException
Admin Servlet
The Admin servlet facilitates administration of the Jeeves server through
a GUI front end.
CgiServlet
This servlet acts as a gateway for the CGI 1.1 interface. This servlet
allows any program that utilizes the CGI 1.1 standard to operate under
Jeeves. For more information on CGI see the
NCSA documentation.
ImagemapServlet
This servlet implements server-side imagemaps, utilizing an extension
of standard NCSA mapfiles. A serer-side imagemap is specfied as follows in
an HTML file:
<A HREF="http://<server-host-name>/imagemap/<map-file-name>">
<IMG SRC="<image-file>" ISMAP>
</A>
Imagemap files may reside anywhere an HTML document can reside. Imagemap
files are in standard NCSA format (see the
NCSA Imagemapping Tutorial for a description). In addition to standard
NCSA features, Jeeves supports the following additions:
- Text only browsers, such as
Lynx, or the
CERN Line Mode Browser are presented with a menu of links when an imagemap
is selected.
- An optional double-quoted string may be added to the end of each line
in the imagemap file which is used as a descriptive string in the
menu generated for text only browsers.
- There are two additional directives:
- base
- Defines the base URL for relative URL in the mapfile. The three
valid values are
map
for map relative URLs (the default),
referer
for URL relative to the HTML page containing the
imagemap, or any full URL.
- text
- The doubled quoted string following this directive is inserted into
the menu generated for text only browsers.
jeeves@java.sun.com
Last modified: Mon Aug 05 04:50:00 PDT