Generating XML from template file.

[Mani Ram]

I have to generate XML documents dynamically from a template file and a flat file containting the values

For example, say I have a Template like this

<MyData>
  <Name>
    <FirstName></FirstName>
    <LastName></LastName>
  </Name>
</MyData>

And the flat file will have something like

Name.FirstName=Mani
Name.LastName=Ram

I need to merge these 2 files and get the following output

<MyData>
<Name>
  <FirstName>Mani</FirstName>
  <LastName>Ram</LastName>
</Name>
</MyData>

What are all the possible ways to do this?
Are there any tools available to do this?

[Lasse Koskela]

Here's something to start from:

public Document getDocumentInstance(String pathToTemplateFile, String pathToVariableFile) {
    Document template = parseXmlTemplateIntoDomTree(pathToTemplateFile);
    Properties variables = new Properties();
    variables.load(pathToVariableFile);
    Iterator keys = variables.keySet().iterator();
    while (keys.hasNext()) {
        String key = (String) keys.next();
        String value = variables.getProperty(key);
        setValueIntoTemplate(template, key, value);
    }
    return template;
}
 
public void setValueIntoTemplate(Document template, String key, String value) {
    Node node = locateNodeBasedOnKey(template, key);
    removeAnyChildNodes(node);
    node.appendChild(template.createTextNode(value));
}
 
private Node locateNodeBasedOnKey(Document template, String key) {
    // parses the 'key' into 'tokens' and navigates in the DOM tree
    // accordingly, finally ending up at the Node the key points to
}
 
private void removeAnyChildNodes(Node node) {
    // goes through all children of the given Node and removes them
}

[Mani Ram]

Thanks for the reply Lasse.
I should have explained it bit clearly in my initial post. Actually I was looking for various possible ways to acheive this. Using Java is one way, but is there some other way?
I need this tool to be as generic as possible. It should be possible for me to modify the variable file and / or the template file with out changing the code.
I could very well use your logic and create this utility, but I would like to check if there are any tools available to acheive the same.

[Lasse Koskela]

How about using simple variable placeholders like <some-element>@myvariable@</some-element> and run a brutal search-and-replace over the whole document? That should work regardless of how the template is changed as long as the expected variable placeholders are found somewhere within the document. Similarly, you wouldn't need to touch the code unless you change the way you mark-up your variable placeholders.