Publishing Engine Programmer's Guide > The Arbortext Publishing Engine Sub-Process
  
The Arbortext Publishing Engine Sub-Process
Implementing Arbortext PE Applications
An Arbortext PE Application is custom code that runs in an Arbortext PE sub-process. An application is invoked by the Arbortext PE Request Manager in response to an HTTP request that specifies a class or function name. The purpose of the application is to process the request, generate an appropriate HTTP response, and return the response to the Arbortext PE Request Manager for transmission to the requesting client.
An Arbortext PE Application can use any of the AOM interfaces and ACL functions within an Arbortext PE sub-process to manipulate documents. Because Arbortext PE sub-processes run in batch mode, you can only use interfaces or functions that are not related to the graphical user interface.