code: public URI resolveUri(URI targetUri, URI srcOrigUri, URI srcId) {
          if(targetUri.isAbsolute()) {
              return targetUri;
          } else if(srcOrigUri==null || !srcOrigUri.isAbsolute()) {
              return targetUri;
          } else {
              return srcOrigUri.resolve(targetUri);
          }
      }
docs: TODO use config to set to use id instead of orig source