xml-utilities : High Level XML Java Utility APIs

I have been working on Java with XML since 2002. It used to be quite confusing and complex to get the value of a tag for example as it required to get into Node level. Here’s an example:

[xml]
<books>
<book>
<title>Book1</title>
<prod id="33-657" media="paper"></prod>
<chapter name="Introduction to XML">
<para>What is HTML</para>
<para>What is XML</para>
</chapter>
<chapter name="XML Syntax">
<para>Elements must have a closing tag</para>
<para>Elements must be properly nested</para>
</chapter>
</book>
<book>
<title>Book2</title>
…
…
</book>
</books>
[/xml]

From functional point of view, I may be interested to get book names. So instead of going into familiar low-level Element and Node route, here’s what I prefer:

[java]
List<String> bookNames = DomEditor.getTagValues("title", document);
[/java]

If you see the underlying implementation of DomEditor, you will realize that you were actually not interested in its implementation as it seems to be complex enough. We created these utility classes a long time back and because of lack of similar APIs I kept on copying these APIs in different projects. As still I couldn’t find APIs in commons-xml the way I could for String in commons-lang, I thought it will be a good idea to create a library just for that.

The APIs are available on Maven Central Repository and the project is hosted on https://github.com/vashishthask/xml-utilities.

Some more APIs Examples

DomEditor
For getting the first Element with tagname “chapter” of the XML, we can use following API.
[java]
Element elmt = DomEditor.getElement("chapter", doc);
[/java]
As this XML contains more than one elements for “chapter” tag we can get the array of these elements too if needed using following API.
[java]

List<Element> elements = DomEditor.getElements("chapter", doc);
[/java]
Within “chapter” element we have multiple “para” elements which we can retrieve using getElements(String, Element) method by passing elmt element.
[java]
List<Element> paraElements = DomEditor.getElements("para", elmt);
[/java]

We can directly retrieve the value of all “para” tags using DomEditor.getTagValues(Element element, String tagName) method.
[java]
List<String> paraTagValues = DomEditor.getTagValues(elmt, "para");
[/java]
DomEditor also provides APIs for some main XML operations on DOM:

• deleting a tag from a XML Element deleteTag(Document, String)
• checking whether tag exists in DOM object checkTagExists(Document, String)
• inserting a new tag in the DOM object insertNewTag(Document, String, String)
• getting a value of a node based on XPath provided in “.” separated String. So in above XML using DomEditor.getNodeValue("title.prod.para", elmt) will give “What is HTML” as resultant.

PrettyPrinter

Useful for printing formatted XML to a file or to console.

DomParser

Direct APIs for parsing a file, String, InputStream etc.