The ACR is a programming interface provided by the Astrogrid Workbench. It presents a simple facade from which to call VO services, and hides the complexity of the system (e.g. the configuration, authentication, service resolution, etc).
The ACR can be accessed via JavaRMI, XMLRPC or HTTP. To date the interface has been called from Python, Perl, Java, C++ and C#. The interface is suitable both for light scripting work (for example automating execution of a series of astronomical data queries and processing stems); and for accessing VO services from other UI applications (e.g. Aladin).
The functions of the ACR and the various ways to connect to the runtime are documented here:
An alternative lower level method to connect to AstroGrid services is to use the Java client-side libraries and web-service stubs used internally in the system. The libraries, and their dependencies, are distributed as Client Development Kits. However, the libraries are only usable from Java programs, and expose developers to the internals of the AstroGrid system.
It's also possible to call the SOAP web services directly. This is the most basic access method, and requires extensive understanding of the VO system - authentication, service location and other low-level concerns all have to be handled by the client programmer.
The set of WSDL and XML Schema that define the AstroGrid web services are available here
An introduction to the software architecture of the Astrogrid v1.1 system was prepared for the AstroGrid Oversight Committee of September 2005. A MS-Word version of the architecture document is also available. Please note that this architecture document is introductory rather than complete. Some aspects of the system are omitted or simplified.
Note that AG v1.1 and AG 2006.2 share the same Architecture documentation.