Description of the Proposed Application

General Description

The CLF will provide the types of system monitoring which will enable Java Applications to be successful at Union Pacific Railroad. Many of these monitoring types will be application specific. For example, the Equipment Tracing application uses the Metrics Gathering System to log:

• total execution time
• number of requests processed
• number of pieces per request
• the user-id for each request
• whether the request completed successfully or failed

The CLF services will enable support organizations to be proactive in monitoring and troubleshooting Web based applications written with the Java programming language. Every Java program will log a beginning and an ending execution point with the MGS (Metrics Gathering Service). This will give support groups a way to measure overall application performance.

First a historical performance base needs to be established; this historical base can be used to monitor current application performance. This historical base will be built from the Metrics Gathering logs. If current performance begins to look out of line with the historical information, the support group may turn on debugging to determine why performance has started to deteriorate.

If the CLF application encounters an unexpected situation, the CLF server can notify a central monitoring support group that a critical situation has occurred. This will minimize outages since the application noticed the error instead of waiting for a user to notify the support group.

Support groups can review these logs to help ensure overall application health proactively.

As errors are detected by the Common Error Handler, support groups can turn on "debug mode" so critical information to analyze the problem can be gathered immediately. It is expected that collecting debug information will negatively impact application performance.

Project Scope

This project will focus on providing three things:

1. Interfaces needed by the Applications to send CLF messages to the Web server
2. CLF server(s) and local data repositories
3. Remote interfaces on the CLF server

This project will not build the actual remote monitoring system.

Remote Method Invocation (RMI)

The CLF system will be built using the Remote Method Invocation (RMI) facility that introduced in the Java 1.1 release. RMI allows code on the client application to invoke a method on a remote object existing on the server. The Java code that calls the remote method is the client for that call, and the computer hosting the object that processes the call is the server for that call. These roles can be reversed such that the server of a previous call is now the client and the client of the previous call is now the server.

When the client wishes to use RMI it calls an actual method contained in the client. This client code is called a "stub" since it contains just the code needed to find and call the actual server object.

(Harold, 1997)