Case Study: Usable and Unusable APIs


It was the best of times, it was the worst of times…

It was the age of wisdom, it was the season of light.  A great library called dom4j was written with its users in mind.  It included a quick start guide and a cookbook for people that actually wanted to get things done.  Converting a document to a String took 15 characters: document.asXML().  But there were too many competing XML parsing implementations, so a standard was created.  And sadly, dom4j has not been updated to adhere to that standard.

It was the age of foolishness, it was the epoch of incredulity.  15 characters to turn a document into a string?  That is far too few.  What will we tell our managers when they ask how many lines of code we have written?  We have a better way and it is called Xerces:


import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;

import org.w3c.dom.Node;

public final class XmlUtil {

  private static final TransformerFactory factory = TransformerFactory.newInstance();

  public static String toString(Node node) {
    if (node == null) {
      return null;
    try {
      Source source = new DOMSource(node);
      StringWriter stringWriter = new StringWriter();
      Result result = new StreamResult(stringWriter);
      Transformer transformer = factory.newTransformer();
      transformer.transform(source, result);
      return stringWriter.getBuffer().toString();
    } catch (TransformerConfigurationException e) {
    } catch (TransformerException e) {
    return null;

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