Such frameworks do exist. Spring, amongst others, allows you to do that in the Java world (http://springframework.org/ http://springframework.org/). Edit: beca

Such frameworks do exist. Spring, amongst others, allows you to do that in the Java world (http://springframework.org/ http://springframework.org/). Edit: because a simple link to the website won't tell you a whole lot about the idea behind it, here's a shot at explaining the basic premise of the core of the Spring framework. Instead of hard wiring objects, you let Spring handle it for you through dependency injection. You simply specify that you want an "authentication" object and the framework will go ahead and look it up. Whether it's an LDAP authentication object or something for a different backend is determined by the context, which you can specify in XML or annotations.