Thanks Andrea for the help! For graph generation I mean that I'd like to materialize subgraphs of my overall knowledge starting from some root nodes whose rdf type is of interest (something similar to what JSON-LD does). Is that clear? On Mar 22, 2015 1:09 PM, "Andra Lungu" <lungu.an...@gmail.com> wrote:
> Hi Flavio, > > We don't have a specific example for generating RDF graphs using Gelly, but > I will try to drop some lines of code here and hope you will find them > useful. > > An RDF statement is formed of Subject - Predicate - Object triples. In Edge > notation, the Subject and the Object will be the source and target vertices > respectively, while the edge value will be the predicate. > > This being said, say you have an input plain text file that represents the > edges. > A line would look like this : http://test/Frank, marriedWith, > http://test/Mary > > This is internally coded in Flink like a Tuple3. So, to read this edge file > you should have something like this: > > private static DataSet<Edge<String, String>> > getEdgesDataSet(ExecutionEnvironment env) { > if (fileOutput) { > return env.readCsvFile(edgesInputPath) > .lineDelimiter("\n") > > // the subject, predicate, object > > .types(String.class, String.class, String.class) > .map(new MapFunction<Tuple3<String, String, String>, > Edge<String, > String>>() { > > @Override > public Edge<String, String> map(Tuple3<String, String, > String> tuple3) throws Exception { > return new Edge(tuple3.f0, tuple3.f2, tuple3.f1); > } > }); > } else { > return getDefaultEdges(env); > } > } > > After you have this, in your main method, you just write: > Graph<Long, String, String> rdfGraph = Graph.fromDataSet(edges, env); > > I picked up the conversation later on, not sure if that's what you meant by > "graph generation"... > > Cheers, > Andra > > On Sun, Mar 22, 2015 at 12:42 PM, Flavio Pompermaier <pomperma...@okkam.it > > > wrote: > > > Is there anu example about rdf graph generation based on a skeleton > > structure? > > On Mar 22, 2015 12:28 PM, "Fabian Hueske" <fhue...@gmail.com> wrote: > > > > > Hi Flavio, > > > > > > also, Gelly is a superset of Spargel. It provides the same features and > > > much more. > > > > > > Since RDF is graph-structured, Gelly might be a good fit for your use > > case. > > > > > > Cheers, Fabian > > > > > >
