How to? Get selected link > get its metadata > search for dcr's with simular metadata

System

Livesite 7.1
New to this component thing. I have been to training but it did not cover the java api's that much. So in an external I need a way to get the dcr path of the currently selected link or do I parse it out of RequestContext.getRequest.getPathInfo()? Once I have the DCR path I want to get the metadata on the DCR. Then get a list of DCR's that have the same metadata set on them. The example is a visitor to our site selects a facility link. The facility has metadata of the specialties at the facility. I want to get a list of articles that have the same specialty metadata set on them.