bar graph

2D / 3D Horizontal Bar Graph Documentation

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Retrieving Data from Files

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.

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,


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,




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,,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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Getting Started




Common Problems
This section describes and provides solutions to common problems.