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Step 3 - Set up the Graph Data
As with the configuration data there are two options for supplying the data values to the servlet,
a) Data File.
The servlet will read all the data from a specified file. To use this option incorporate the url of the data file into the
the IMG tag (see Step 4).
The "../../area_graph/Documentation/areadata.txt" file contained in this directory is an
example file containing the data ( click here to view the example file ).
As you will see from the example file each piece of data is specified on a name, value basis.
Simply create a similar file adding your data in the values. For a
full explanation of this file please see the "Retrieving Data from Files" under the "Data and Configuration"
section ( or click here).
b) Server Side process
This option is the most powerful and gives the servlet the ability to retrieve data from databases. This method involves
specifying a server side script in the <IMG> tag of the html page (see Step 4) which in turn returns the data to the
graph servlet, giving enormous flexibility for data acquisition. The server side script can be constructed in the language
of your choice and as such can be written to acquire data from the widest variety of sources, multiple databases etc.
To instruct the servlet to retrieve data from a server side script simply
add the URL of your server side script into the <IMG> tag of the HTML page (see Step 4). The server side script should
be designed to output the data in the same format as the file in option a) above.
For an example script see AreaDataServlet.java
in the ServerTemplateScripts directory.
For a full description of constructing a server side script which retrieves
data from a database see the section "Connecting the Graph to a database" under the "Data and Configuration"
section ( or click here).
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