Programming Jakarta Struts

Creating an Automated Build Environment

Once you have put together a satisfactory build environment, you should go the extra step to automate it. This means that no human interaction is needed to execute new builds. It’s very common for build frequencies to increase the closer you get to the end of a construction phase. You can, of course, just manually kick off builds when you need them, but a better and much more efficient approach is to use a scheduling mechanism to invoke your Ant build environment.

There are at least two scheduling mechanisms that you can employ, depending on your environment. In Unix, you can use the cron daemon, and on the Windows platform, you can take advantage of the Task Scheduler.

Using cron to Invoke Ant

cron is a program that allows you to automate tasks by running user-defined programs at regular intervals. cron allows you to define both the program that is to be run and the exact time at which to run it. The cron program is a daemon program, which means that it runs in the background until it’s needed. It wakes up every minute, checks to see if there are any scheduled tasks that need to be performed, and, after it runs the tasks, goes back to waiting.

The list of tasks for cron to execute comes from a file called a cron table, which is commonly referred to as crontabs. The crontabs is a schedule that lists the tasks to run and the date and time to run them.

Tip

Some system administrators may disable cron from running on a server in order to save ...