Hierarchy is a meta-compiler that extends the Java language to add support for XML-like hierarchical data. The video provides us with code examples and demos the use of three new file types that Hierarchy adds to Java (.matrix, .schema, & .mjava). Hierarchy seems like the natural evolution of working with data: JavaScript has had JSON for years and C# has had LINQ. Hierarchy tries to combine the best of these two technologies and pushes them even further.
The XML technologies for Java are very good at working with XML. For instance, JAXB’s annotations make it relatively easy to setup the loading of XML into applications. But, the difference between using annotations or class libraries to work with XML, as opposed to using a dedicated data-structure is pretty significant. Having a data structure that’s directly apart of Java makes working with hierarchical data immensely easier. Using JAXB, it’ll take roughly 40 to 50 minutes to create and debug a decent-sized mapping from Java classes to XML. With Hierarchy, it takes about 20 minutes to create matrices of the same size.
Organizer: SF Java User Group
Video source and slides: http://marakana.com/s/video_why_java_needs_hierarchical_data,573/index.html