Publication.xml is the file that determines what content will be drawn into the publication and where it will be placed. It contains one or more Article elements, each containing the following attributes:

For the purposes of this application, if an Article element has an xlink:actuate value of "onLoad", then the xlink:show attribute must have a value of "embed". Otherwise,it would result in either the article being the only one displayed (xlink:show="replace") or opening up a second window when the publication is opened (xlink:show="new").

The Article element may also contain a Description element, which may be used to include a description of the article. This will be useful when the xlink:actuate attribute is set to "onRequest"; the user will be able to read the description of the article before deciding whether to 'request' the article or not.

Here is an example of a Publication.xml instance:

          <Publication title="My New Publication" xmlns:xlink="http://www.w3.org/1999/xlink">
            
            <Article priority="3" xlink:type="simple" 
                                  xlink:href="http://www.umassx.edu/VP/Article_C.xml" 
                                  xlink:title="Article C Title"
                                  xlink:show="embed"
                                  xlink:actuate="onLoad"/>
            
            <Article priority="2" xlink:type="simple"
                                  xlink:href="http://www.myplace.net/VP/Article_B.xml"
                                  xlink:title="Article B Title"
                                  xlink:show="embed"
                                  xlink:actuate="onRequest">
              <Description>This is a description of Article B. If you would like to read the article,
                           just click anywhere on this text and it will appear here.</Description>
            </Article>
            
            <Article priority="1" xlink:type="simple"
                                  xlink:href="http://www.yourplace.com.au/Article_A.xml"
                                  xlink:title="Article A Title"
                                  xlink:show="embed"
                                  xlink:actuate="onLoad"/>
            
            <Article priority="4" xlink:type="simple"
                                  xlink:href="http://www.nowhere.org/VP/Article_E.xml"
                                  xlink:title="Article E Title"
                                  xlink:show="new"
                                  xlink:actuate="onRequest">
              <Description>This is a description of Article E. If you would like to read this article,
                           just click anywhere on this text and it will open in a new window.</Description>
            </Article>
          
          </Publication>
        

Article.xml can be based on any schema you desire, as long as all your articles are instances of the same one and Article.xslt is able to transform them into the desired format.

This is the file that does all the work. It evaluates the Publication.xml file and creates the XHTML that will be delivered to the users' browser. As might be expected, most of the work is done within a single template, for the Article element.

The first thing it does is create a div element with the value of the class attribute determined by the value of the priority attribute of the Article element.

          <xsl:element name="div">
              <xsl:attribute name="class">Pri<xsl:value-of select='@priority'/></xsl:attribute>
        

This class attribute will then be referenced in Publication.css to determine the position and formatting of the article in the VP.

Next, it evaluates the value of the xlink:actuate attribute to determine whether to include the entire article in the VP as it loads(xlink:actuate="onLoad") or just a link (xlink:actuate="onRequest") that will display the article when activated.

If the article is to be displayed when the VP is loaded, the stylesheet uses the xlink:href attribute to locate the article and the document() method to pull it into the VP.

          <xsl:variable name="Source"><xsl:value-of select='@xlink:href'/></xsl:variable>
          <xsl:variable name="Content" select="document($Source)"/>
          <xsl:apply-templates  select="$Content"/>
        

This code takes advantage of the fact that we 'imported' the Article.xslt into the Publication.xslt using the xsl:import construct. The reason I chose this method of pulling in the Article stylesheet, rather than xsl:include, is because it allows the definitions and template rules in the Publication stylesheet to take precedence over the ones in the Article stylesheet. This will eliminate any unanticipated affects from template rules in the Article stylesheet.

If only a link to the article is to be displayed when the VP is loaded, the stylesheet evaluates the value of the xlink:show attribute to determine the action to perform when the link is activated. If the article only needs to be opened in a new window (xlink:show="new"), or replace the content of the existing window (xlink:show="replace"), we simply create a regular XHTML hyperlink with the value of the Description element becoming the displayed text of the link. We can use the target attribute of the <a> tag to indicate where the article is be opened (target="_blank" to open in a new window or target="_self" to replace the content of the existing window).^{[1] [1]}

          <xsl:when test="@xlink:show='new'">
            <a>
              <xsl:attribute name="href"><xsl:value-of select="@xlink:href"/></xsl:attribute>
              <xsl:attribute name="title"><xsl:value-of select="@xlink:title"/></xsl:attribute>
              <xsl:value-of select="Description"/>
            </a>
          </xsl:when>
        

However, if the article is to be embedded in the existing page (xlink:show="embed") we have quite a bit more work to do. First, an XML data island is created with the src attribute set to the value of the xlink:href attribute; this will identify the source of the transformation when the link is activated. Next, we create a div element that contains the hyperlink to the article. This same element will also contain the article itself when the link is activated.

          <xsl:when test="@xlink:show='embed'">
            <xsl:element name="xml">
              <xsl:attribute name="id">Source<xsl:value-of select="@priority"/></xsl:attribute>
              <xsl:attribute name="src"><xsl:value-of select="@xlink:href"/></xsl:attribute>
            </xsl:element>
            <div>
              <xsl:attribute name="id">Div<xsl:value-of select="@priority"/></xsl:attribute>
              <a>
                <xsl:attribute name="onClick">call getContent(Div<xsl:value-of select="@priority"/>,Source<xsl:value-of select="@priority"/>)</xsl:attribute>
                <xsl:attribute name="title"><xsl:value-of select="@xlink:title"/></xsl:attribute>
                <xsl:value-of select="Description"/>
              </a>
            </div>
          </xsl:when>
        

The getContent() function called by the onClick event is a script that replaces the hyperlink text with the actual article it references.^{[2] [2]}

          <script TYPE="text/vbscript">
            Function getContent(Target,Source)

              Target.innerHTML = Source.transformNode(Style.xmlDocument)

            End Function
          </script>

          <xml id="Style" src="Stylesheets\Article.xslt"></xml>
        

The Target input to this function is the ID of the div element into which the article will be placed. The Source input is the ID of the XML data island which references the article we wish to display. The function replaces the current contents of the 'Target' <div> with the result of the transformation of the 'Source' xml via the Article.xslt stylesheet.

The stylesheet will then repeat this process for each Article element contained in the Publication.xml file.

This is the file that transforms the content of Article.xml into the desired format to be displayed within the Virtual Publication. You can use any stylesheet that is designed to transform the Article.xml file you are using. The Virtual Publication gains access to this file via the <xsl:import href="Article.xslt"/> statement in the Publication stylesheet. The Article stylesheet should be designed to take into account that Publication.xslt will provide all the necessary XHTML opening code.

This file handles the formatting for the Publication as a whole, rather than the individual articles. Its most important function is to define the location and general look and feel of the Articles included in the Publication. It does this by declaring a style block for each of the classes assigned to the div elements that contain the Articles.

          .Pri1{
              font-size: 12pt;
              background-color: #CCFFFF;
              position: fixed;
              width: 100%;
              border: thick;
              border-style: groove;
          }
          .Pri2{
              font-size: 10pt;
              background-color: #CDCCFF;
              position: absolute;
              width: 50%;
              border:thin;
              border-style: groove;
          }
          .Pri3{
              font-size: 10pt;
              background-color: #FFCCFE;
              position: absolute;
              left: 50%;
              width: 50%;
              border:thin;
              border-style: groove;
          }
        

The article that was given a priority of '1' in the Publication.xml file is placed at the top of the window and spans its entire width. It is also assigned a larger default font size than the other articles. The articles given a priority of '2' and '3' are placed below the 'main' article, side by side, each taking up 50% of the width of the window. The other articles can be placed in a similar fashion.^{[3] [3]} Each article is also given a different background color.

This stylesheet, like the Article.xslt stylesheet, is simply used to define the style and formatting of the individual articles. Any appropriate stylesheet can be used and can be plugged in via the style element produced in the Publication.xslt file.

          <style type="text/css">
            @import url(Stylesheets/Publication.css);
            @import url(Stylesheets/Article.css);
          </style>
        

Elements representing monthly columns need never be altered. The content is automatically updated when the new column is submitted. As far as the author is concerned, submitting the article may only consist of replacing the previous article on his own server. Authors retain complete control of their own content.

A department head can get up-to-the-minute status reports of any project or combination of projects. Each Project Manager is responsible for his own status report which can reside on any computer, in any directory, that the Department Head has read access to. Whenever the Project Manager needs to update something in his report, he simply edits the copy on his machine and, the next time the Depatment Head opens her 'template', she will have the latest update.