Comments on: A Fluent Interface for XML DOM APIs

By: Stefan Tilkov

Stefan Tilkov — Sun, 13 May 2007 17:54:21 +0000

In Ruby:

require 'builder'
x = Builder::XmlMarkup.new(:target => $stdout, :indent => 2)
x.contacts {
  x.contact {
    x.name('John Doe')
    x.phone '555-12345', :type => 'home'
    x.phone '555-67890', :type => 'work'
  }
}

By: Erik-Jan Blanksma

Erik-Jan Blanksma — Fri, 11 May 2007 20:06:12 +0000

I had a go at creating a utility class that mimmicks the Xlinq API. Here's what I came up with:

class XElement{ List children = new ArrayList(); Listattributes = new ArrayList(); final String name; String text;



public XElement(String name){
    this.name = name;       
}

public XElement(String name, String text, XAttribute... xAttributes){
    this(name);
    this.text = text;   
    attributes.addAll(Arrays.asList(xAttributes));
}

public XElement (String name, XElement... xElements){
    this(name);
    children.addAll(Arrays.asList( xElements));
}

public Document toDocument(){
    return build(this);
}

public static Document build(XElement xElement) {
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db;
    try {
        db = dbf.newDocumentBuilder();
    } catch (ParserConfigurationException e) {
        throw new RuntimeException(e);
    }
    Document doc = db.newDocument();
    doc.appendChild(buildElement(doc, xElement));
    return doc;     
}

public static Element buildElement(Document document, XElement xElement){
    Element element = document.createElement(xElement.name);
    for (Iterator iter = xElement.attributes.iterator(); iter.hasNext();) {
        XAttribute attribute = (XAttribute) iter.next();
        element.setAttribute(attribute.name, attribute.value);
    }
    if(xElement.text!=null){
        element.setTextContent(xElement.text);
    }else{
        for (XElement childElement : xElement.children) {
            element.appendChild(buildElement(document, childElement));                  
        }
    }
    return element;     
}


}

class XAttribute{
    final String name;
    final String value;

public XAttribute(String name, String value){
    this.name = name;
    this.value = value;     
}

}

To create a document: Document doc = new XElement("contacts", new XElement("contact", new XElement("name", "John Doe"), new XElement("phone", "555-12345", new XAttribute("type", "home")), new XElement("phone", "555-67890", new XAttribute("type", "work")) ) ).toDocument();

By: Dan Diephouse

Dan Diephouse — Thu, 10 May 2007 17:26:32 +0000

I like the idea. I think it’d be great to make this a “single class library”. I.e. you could just create a class and various people can stick it in their util directory instead of Yet Another Jar.

Groovy isn’t the solution for all things because I don’t necessarily want to embed groovy in all my apps just to do this.

By: Craig Wals

Craig Wals — Thu, 10 May 2007 04:05:53 +0000

Anticipating Guillaume’s next question: Why do you need to use it in Java? Why not just use Groovy markup in a Groovy class, then have your Java code delegate to that class for XML handling? Push all of your XML access code into a DAO-like class (XAO?) and then call that whenever you need to create some XML.

By: Arjen Poutsma

Arjen Poutsma — Thu, 10 May 2007 00:50:19 +0000

@Guillaume,

Yeah, the Groovy Markup builder is definitely fluent as well; I forgot to mention it. Writing a fluent interface in a more dynamic language like Groovy is easier in a way. The only downside is that I cannot use it in Java.

By: Guillaume Laforge

Guillaume Laforge — Thu, 10 May 2007 00:26:22 +0000

What about Groovy's Markup builder?

def mkp = new MarkupBuilder()
mkp.contacts {
   contact {
      name("John Doe")
      phone(type: "home", "555-12345")
      phone(type:"work", "555-67890")
   }
}