XML Poll                                              Page 1 - 3



Date:	2:30 PM 9/21/2002
By:	M.Meijer
	

				XML Poll

Table of contents
   
   1. Introduction..........................................   1
   2. Files.................................................   1
   3. Interfaces............................................   2
   4. Implementation considerations.........................   3
   5. Example usage.........................................   3





1.  Introduction

    The basic of this XML Poll is a way to save data to XML file
    and display this data from it. It's easely expandable, just
    add some more attributes to the XML elements.
    

2.  Files
   
    The files are 3 asp files: "edit.asp, index.asp, 
    include.asp", to edit and view the Poll, 1 transparent pixel
    ("trans_pix.gif") and the "poll.xml".

    poll.xml
       The "poll.xml" file holds the poll data. It starts with
       root element named "statement". The "value" attribute
       is holds the statement.
       The statement element can contain 1 or more "option" 
       elements, "option" elements are the options a user has
       to vote. The "option" has 3 attributes.

       option element:
           1. id, defines a unique id for the option.
           2. hits, defines the amount of votes.
           3. value, contains the option's value.
       
    include.asp
       In the "include.asp" file are some simple functions and
       the classes to interface with the xml file.
	
    edit.asp
       The "edit.asp" is a asp script to edit the "poll.xml file".
       It displays a form to edit the statement value and create,
       remove, and edit options.

    index.asp
       The "index.asp" displays a form to vote for a statement,
       diplays the current status.
       
    trans_pix.gif
       This is a 1x1 transparent GIF.



XML Poll                                              Page 2 - 3



3.  Interfaces

    There are 2 classes to interface with the "poll.xml", oOption
    and oStatement.

    +---------------------------+  +----------------------------+
    |oStatement			|  |oOption			|
    +---------------------------+  +----------------------------+
    |Value			|  |Value			|
    |DataFile			|  |Id				|
    |DataLoaded			|  |Hits			|
    |Error			|  +----------------------------+
    +---------------------------+  |  				|
    |LoadData()			|  +----------------------------+
    |Edit()			|
    |ChangeOption()		|
    |CreatOption()		|
    |RemoveOption()		|
    |Options()			|
    |IncreaseOption()		|
    +---------------------------+


    oStatement:

        -Value		The current value of the statement.

        -DataFile	The filename of the datafile, if loaded.

        -DataLoaded	If a datafile is loaded correctly,
			this will be a boolean TRUE, else FALSE.

        -Error		An error message if occured.

	-LoadData()	The function to load a datafile, the file
			as argument, it will return a boolean TRUE
			if the file is successfully loaded else
			FALSE.

	-Edit		To set the statement's value, the value
			is expected as argument.
			The function will return TRUE on success,
			else FALSE.

	-ChangeOption	To change an "option", call this funtion
			with the "Option.id", and "Option.Value"
			as arguments.
			It will return a boolean TRUE on success,
			else FALSE.

	-CreateOption	To create a new "option", call this
			function, the "Option.Value" is expected
			as argument.
			It will return a boolean TRUE on success,
			else FALSE.
			The "Option.Id" will be generated
			automatic inside the function.

	-RemoveOption	To remove an "option", call this function
			and give it the "Option.Id" as argument.
			If the function succeeds it will return
			a boolean TRUE, else FALSE.

	-Options	To get all "options" from the "statement".
			It will return an array type with "option"
			objects.

	-IncreaseOption To increase an option's hits call this 
			function send the "Option.Id" as argument.
			It will return a boolean TRUE on success,
			else FALSE.



XML Poll                                              Page 3 - 3


    
    oOption:

	-Value		The value of the "option".

	-Id		The id of the "option", this is the unique
			identifier for the "option".

	-Hits		The amount of hits a specific "option" has.


3.  Implementation considerations

    The examples show an implementation of a poll with the 
    serverside scripting technologie ASP. Due the openess of
    XML and simplicity of the definition of the poll,it can be
    implemented on any system capable running RPC's.


5.  Example usage
    
    To use the example files, just get any computer capable of
    running ASP and the MS XML4.0 processor. Edit the "include.asp"
    file's "STR_DATA_FILE" constant to define the absolute path
    to the XML datafile.

    XML Processor used: "Msxml2.DOMDocument.4.0"
    
    The script is tested on a WinXP PC running IIS5.1

&EOF