Origins of this project: some best practices

For a single server scenario this can be achieved with combining it with Tomcat's parallel deployment feature. [Example]

In a multi server + load balancer set up, this also provides fully transparant fail-over in case of any failure on the hosts.

Project: de.oglimmer.utils


The library helps to prevent boilerplate code for random strings and names, SPI-based slf4j configuration, sophisticated property files, human readable representation of date differences and getting attributes from MANIFEST.FM files.

Source / JavaDoc / Binaries

The sources can be found at github. The javadoc can be found at here. Download/use the latest binaries from maven central.

Detailed information with examples

Class: de.oglimmer.utils.VersionFromManifest

Helps to read attributes from a Manifest file and provides a uniform "version" string which has version, git-commit, creation date and a html-link to git

An example project is on github.

1.) add this to your pom.xml, to add the information into the MANIFEST.FM file: 2.) add this to your pom.xml to retrieve the git commit hash: 3.) use a ServletContextListener.contextInitialized(ServletContextEvent) to get a proper version string

Class: de.oglimmer.utils.BaseConfigurator

Implements SPI-based slf4j configuration. It changes the order and places where slf4j looks for configuration files. The "APP_NAME" is given as a parameter in the constructor. Checks first the system parameter "APP_NAME"-logback for a filename, if this parameter is not given or the file doesn't exist it looks in /etc/logback-custom.xml. If all this doesn't exist it uses /logback-custom.xml in the $CLASSPATH. It also sets the slf4j variable "application-name" with the "APP_NAME".

  1. Create a class in your project and extend it from de.oglimmer.utils.BaseConfigurator
  2. Have a parameter less constructor and set your application name in super("....");
  3. Create META-INF/services/ch.qos.logback.classic.spi.Configurator under src/main/resources
  4. Put the full qualified filename of your class from (1) into that file
  5. make sure you have a logback-custom.xml in your project (and not logback.xml)

Class: de.oglimmer.utils.AbstractProperties

A base class for application property classes. Supports json-based config files, automatic reloads when the file changes, merging in-classpath and out-of-classpath files and can take the whole configuration from a string to support unit test configurations.

  1. Create a (singleton) class in your project and extends it from de.oglimmer.utils.AbstractProperties
  2. Have a parameter less constructor and pass the name of the system parameter to your production config file to super("...."), e.g. super("my_app")
  3. create as many getters as you need like
  4. put a into src/main/resources. this needs to be a json file and should hold all default/development values for all properties
  5. On your production host start the server with -Dmy_app=/etc/