Online Monitoring API

Introduction

The goals of the online monitoring API FAQ is to show how JAS can be used in a client-server based real-time monitoring framework. It documents changes and extensions that have been made in the JAS architecture to support online monitoring applications. These changes were initially motivated by the requirements of the BaBar collaboration, who have used JAS as a part of their online monitoring system. The methodology described here is in no way specific to BaBar however.

The online monitoring API can be used to access histograms which have been created in languages other than Java. It is possible to use either Corba or the Java Native Interface (JNI) to access histograms created in other languages.

Topics covered in this How To include:

• Server API
• Should I use the Server API or write my own DIM?
• Interfacing to existing histograms
• Sending messages from a remote client
• Dynamic loading of experiment specific code
• Example code
• Using HTML pages to display online monitoring info

Server API

The server API is contained in the package jas.server.