I was looking for a mechanism to configure my application during deployment time. We have our own configuration module but it does not handle the case for deployment descriptor. For example, the application needs to connect to different JMS queues in different environment. The JMS queue name is usually specified in the jboss.xml which is wrapped in the ear file. Our old approach is to use an Ant script build the ear file during the deployment time. It is tedious and also makes it difficult to see what is actually configured. Now I discovered a new way to do it. I can actually use ${param_name} inside the jboss.xml and use JBoss's system property service to define the actual value of the parameter in a seperate property-service.xml. By doing that, I can have the ear file created during the build time and deploy it along with an environment specific property file. It works just wonderful.
To know how it is done, you can take a look at org.jboss.metadata.MetaData.java. And here is the documentation from the Javadoc:
Go through the input string and replace any occurance of ${p} with the System.getProperty(p) value. If there is no such property p defined, then the ${p} reference will remain unchanged. If the property reference is of the form ${p:v} and there is no such property p, then the default value v will be returned. If the property reference is of the form ${p1,p2} or ${p1,p2:v} then the primary and the secondary properties will be tried in turn, before returning either the unchanged input, or the default value. The property ${/} is replaced with System.getProperty("file.separator") value and the property ${:} is replaced with System.getProperty("path.separator").
