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Both
the applet and servlet can be set to retrieve the graph
data from a data file. The data file is simply a list
of the data names with the value for each data element
of the graph.
The
first element of a line in this file specifies the data
element name whilst second represents the value for
that data element.
Comment
Lines: Any line in the file which is either
blank or begins with <!-- will be ignored. Therefore
comment lines may be added to the file by beginning
the line
with <!--. |
We
recommend that, rather than building a data file from
scratch, that you take a copy of the example file bardata.txt
file and modify the values to suite your implementation.
In
both the applet and servlet, the data file is specified
via a URL parameter and therefore the file can be placed
in any directory (or server) accessible via a URL. However
we recommend,for ease of maintainability, keeping this
data file in the same directory as your web page which
incorporates the area graph.
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Data
Element Naming Convention.
The
graph is capable of displaying multiple series
of data in the same chart area and therefore it
is necessary to specify which series each piece
of data belongs. In addition it is also important
to specify the order in which data should be taken
for each series. This is done by the Name of each
element.
The
data name format is,
dataNseriesM:
where
N is an integer number representing this data
position within the series and M is an integer
specifying the series. Both the data and series
numbering should be continuous and begin with
1.
For example if we have 3 series of data each with
four pieces of data the data names would be,
data1series1:
data2series1:
data3series1:
data4series1:
data1series2:
data2series2:
data3series2:
data4series2:
data1series3:
data2series3:
data3series3:
data4series3:
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Data
Values
The
data value for each piece of data can either be
an integer or real / floating point number. In
addition if the data file is being constructed
for use by the applet, two further elements may
be added, which define a URL and a Target frame
for this data's segment. To add a URL and target
frame to a piece of data simply add the URL and
target frame name to the end of the line separating
each with comma "," character.
eg.
data1series1: 7000,http://www.jpowered.com,framename
In
the applet implementation the URL and Target elements
may also be used to execute a piece of JavaScript
within the HTML page. For further details on this
please see the section "JavaScript"
Please
Note: URL and Frame specification is not valid
for the servlet implementation.
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