code: public static Protos.CommandInfo.URI uri(MesosArtifactResolver resolver, ContainerSpecification.Artifact artifact) {
  		checkNotNull(resolver);
  		checkNotNull(artifact);
  		Option<URL> url = resolver.resolve(artifact.dest);
  		if (url.isEmpty()) {
  			throw new IllegalArgumentException("Unresolvable artifact: " + artifact.dest);
  		}
  
  		return Protos.CommandInfo.URI.newBuilder()
  			.setValue(url.get().toExternalForm())
  			.setOutputFile(artifact.dest.toString())
  			.setExtract(artifact.extract)
  			.setCache(artifact.cachable)
  			.setExecutable(artifact.executable)
  			.build();
  	}
docs: Construct a Mesos URI.