Different environment variables per war in tomcat

Question

Is there a way to have different environment variables for different war files in tomcat? I am using a 3rd party war and need to have multiple deployments of the same war b

Answer 1

Ok, total crazy hack idea:

Implement a PropertyPlayHolderConfigurer (or use web.xml from Tomcat) for each app instance and load properties same name as you have for System.properties().

Then, create a delegate Properties class that contains both sets of properties. Then

Properties props = new DelegatingProperties(app1Props,app2Props)
System.setProperties(delegate);

public class DelegatingProperties extends Properties {

   private Properties app1Props;
   private Properties app2Props;

   public DelegatingProperties(Properties app1Props, Properties app2Props) {
        this.app1Props = app1Props;
        this.app2Props = app2Props;   
   }

   public String getProperty(String prop) {
       // begin crazy science
       String caller = new Throwable().getStackTrace()[0].getClassName();
       // this is where you get creative.
       // Do the System.setProperties() above so you can intercept calls to  
       //getProperty()
       // and find out the FQCN of the library class(es) that need these variable 
       // (use your debugger).
       // then implement the logic here to decide which of the 2 property sets you have
       // you will query to get the correct results     
   }
}

These are SYSTEM properties we are talking about and they are meant to apply system wide. Your library was probably developed when it was 1-app-1-jvm (or the developer is a tard which is also likely).

Can I atleast get props for creativity? :)