A hierarchical data repository




Document Index:

Introduction (this page)

Quick Start

User Guide

XSpace Browser



What is XSpace?

XSpace is a repository for hierarchically-keyed information, easily accessible from anywhere by any application.

You can store just about anything in an XSpace – strings, XML documents, serialized objects and URIs.
Think of an XSpace as a kind of hash table, globally accessible, where the keys have a hierarchical naming syntax (e.g. “/a/b/c”).

Or alternatively, think of an XSpace as a persist-able tree.


XSpace supports real-time events; whenever a keyed value is added, updated or deleted from an XSpace, an application is informed of the event.
XSpace lets you perform search starting from any node in the hierarchy.


XSpace is targeted for use by collaborative components within an application and across applications where information needs to be shared. For example, you can use XSpace to:


  1. store for information for content management systems.
  2. store configuration information used and managed by different applications.
  3. store catalog information organized by hierarchical categories.
  4. store access control information for users within hierarchical organizations.
  5. act as a “white-board” for a group of collaborative applications.


Why use XSpace?


  1. We tend to organize information about our world into hierarchical categories. XSpace’s Java API and language-agnostic web services let you navigate hierarchies simply and efficiently.
  2. XSpace is event-driven – any changes to information are immediately delivered as events to interested applications.
  3. XSpace is designed to be simple and easy to set up and use out-of-the-box.
  4. XSpace is built on J2EE and Hibernate – this lets you run it on any J2EE application server and use any database you choose for persistence.
  5. A handy management tool (XSpace Browser) is available that lets you manage XSpaces easily.


What is the licensing model?


XSpace uses the LGPL licensing model. It is free software and you may embed it in any application, commercial or otherwise. However it comes with no warranties.




XSpace is built on top of the J2EE technology stack (specifically stateless session EJB and JMS), Hibernate and Axis. The following diagram illustrates the architecture:

























Flowchart: Magnetic Disk: Persistent





Flowchart: Magnetic Disk: Persistent
Flowchart: Magnetic Disk: Persistent
Where do I go from here?


Download the software, if you haven’t already done so.

Go to Quick Start for installation instructions and how to use the XSpace API.

Take a tour of the XSpace Browser.

Run the examples.

Go to the User Guide to configure XSpace for your environment.