Shadowtail is a Java/Spring framework for gathering numerical
data (statistics) about a Java application, and writing the data to
files. It is particularly useful as a source of data to feed Orca,
the free tool for plotting textual data onto a directory on a Web
Why would you want to use Shadowtail? Shadowtail helps you to
monitor your software application or service by logging application and
application container data over time. The data format is suitable for
plotting or for analysis. Suppose you have a web application selling
widgets. Your sales manager would like to monitor and record application
data on turnover and number of widgets sold, analyzed by day, week and
month. Your operations manager would like to monitor JVM data on heap
usage and number of classes loaded. A combination of Shadowtail, Java
MBeans in your web app, and Orca will give you the data in raw format
and in graphs.
Here is an example graph produced by Orca from data logged by
Shadowtail from an MBean monitoring a count of widget sales in a Java
Use Shadowtail to capture web app data that you wish to persist.
JConsole gives you a snapshot of the data, but Shadowtail and Orca give
you a picture over time. Here are some plots produced by Shadowtail and
Orca of the JVM of a Tomcat instance.
Shadowtail provides Java classes and example Spring
configurations to gather and record:
Shadowtail was written by John Cooke of Black Pepper
Software and prepared for open sourcing by Julia Dain and David Johnson,
also of Black Pepper Software.
Shadowtail's model consists of statistics,
groups of statistics, files, and loggers.
A statistic is the basic unit of
data collection. Statistics are organized into groups.
Groups can be organized into hierarchical trees. The statistics data of
a group is written to a file by a
logger. The pathname of the file
is determined by a file factory
and the group. A model can be instantiated by Spring configuration or by
Copyright (C) 2009 Black Pepper Software Ltd. Author: John Cooke,
Black Pepper Software Ltd. Comments, questions and bug reports should be
submitted via http://sourceforge.net/projects/shadowtail/ More details
can be found at the project home page: http://shadowtail.sourceforge.net
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version. This program is distributed in the hope that
it will be useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details. You should have received a
copy of the GNU General Public License along with this program; if not,