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SimpleXMLDoc revisited

It is 2020, JSON is supposed to have won, with a challenger in sight. XML with its fine distinction between Elements, Attributes and clear ownership demarked by name spaces, was supposed to be gone. But OData made it necessary to look again, as did CalDAV

Out into the OutputStream

The initial version was introduced in the context of XAgents which mandated an OutputStream. I find that adequate and useful, so I kept that. If you just want a String, a ByteArrayOutputStream will do quite nicely

Fluent methods

The big change to the revamped version is the addition of a fluent API. Each method call returns the object instance itself, so you can chain your document creation to look modern (and type less)

Namespace and attributes

Originally I though "simple" would be sufficient to create Elements only. But as time goes by one starts to appreciate name spaces and Attributes, so I added support for these too. To keep things simple: once we specify the namespace at the beginning of the document, we can simply refer to it by its alias name.

A sample:

    final ByteArrayOutputStream out = new ByteArrayOutputStream();
    final SimpleXMLDoc doc = new SimpleXMLDoc(out);
    doc.addNamespace("X", "https://xmen.org")
    .addNamespace("", "https://whyOhWhy.com/xml")
          .addAttribute("name", "A Name")
          .addAttribute("url", "http://anywhere/")
          .addAttribute("meta", "meta not metta"))
     .addSimpleElement("description", "Something useful")

Key methods

  • addNamespace: adds one name space and establishes the alias. To keep it simple, namespaces are defined only at the beginning fo the document
  • setXmlStyleSheet: Same here, needs to be defined at the beginning - after all this class streams the result and stylesheets only start at the beginning
  • OpenElement starts a new XML Element. When provided with a string, it is an attribute free element, that can include the namespace abbreviation. When using a doc.element, we can add attributes
  • addSimpleElement: add an element, its String content and close it
  • closeElement: write out a number of closing tags. It deliberately uses number of tags and not tag names, so you don't need to track the names you have opened. Ensures that XML stays valid
  • closeDocument: closes all remaining Elements in the correct sequence and closes the document. Can be called once only

Check the full source code for details

As usual YMMV

Posted by on 13 April 2020 | Comments (0) | categories: Java XML


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