The Digester Component

Many projects read XML configuration files to provide initialization of various Java objects within the system. There are several ways of doing this, and the Digester component was designed to provide a common implementation that can be used in many different projects.

Basically, the Digester package lets you configure an XML -> Java object mapping module, which triggers certain actions called rules whenever a particular pattern of nested XML elements is recognized. A rich set of predefined rules is available for your use, or you can also create your own.


User documentation is available in the website, you can start reading the Core APIs.

The Release Notes document the new features and bug fixes that have been included in this release.

The "examples" directory in the source code repository contains code which demonstrates the basic functionality. In particular, you should read the AddressBook example in the "api" subdirectory. You can view the examples directly from the Subversion repository via the web-based repository browser web site, or can use subversion to download the files.

For the FAQ and other digester-related information, see the Digester wiki page.


Digester 3.2 (December 2011)

The Digester 3.2 release is a maintenance release that adds the most innovating feature ever, providing the objects Constructor feature.

Take a look at Digester 3.2 release changes list for more details.

Digester 3.2 requires a minimum of JDK 1.5.

The recommended dependency set for Digester 3.2 is:

Recommended Dependency Set
Digester +Logging 1.1.1 +BeanUtils 1.8.3 +CGLIB 2.2.2

Since dependencies increased by number, since 3.2 release, Digester is distributed also in a single artifact with shaded dependencies.

Maven users that want to switch over shaded artifact, must use the with-deps classifier:


Digester 3.1 Release (October 2011)

The Digester 3.1 release is a maintenance release that adds the Asynchronous parser feature.

Digester 3.0 Release (July 2011)

The Digester 3.0 is an almost complete rewrite of the original Digester implementation, which offers:

  • A universal loader: core features and extensions became not so easy to maintain, since every contribution was created with a different approach; a fresh new architecture is able to load modules that allow users write and include easily their own extensions;
  • Reusability of Digester configurations: what was missing is a way to describe how the Digester instances have to be built and not how to set rules given an existing instance;
  • Rules are now expressed via EDSL: the key feature of Digester3 is expressing rule bindings using a fluent APIs collection, that speak more in English rather than in a programming language;
  • Improved errors reporting: rules binding debug operations have made easier, a detailed errors list of wrong binding is reported just when the loader attempts to create a new Digester instance, and not when running it.

Acknowledgements: The Digester 3 has been inspired by special people:

  • Rahul Akolkar, for mentoring;
  • James Carman, who had the initial idea of building a Digester with fluent APIs;
  • Matt Benson, for having influenced on DSL;
  • Daniele Testa [mrwolfgraphics AT gmail DOT com], who provided the Digester3 logo.