Beginner #292

Maatary · 2015-08-11T18:21:09Z

Hi,

I am looking to add Banana-rdf to my project however i am a little puzzled as to how to proceed.

Could you please clarify the following point for me:

1 - Banana-rdf is not available as artifacts online such as on bintray or maven central, etc....

2 - You have to build and publish all the artifact yourself.

3 - After which you have to add the artifact to your project. In that regard, what artifact are required in case you just want to have a sparql engine, to query some external sparql endpoint.

4 - Why isn't it possible to simply import things instead of creating a full class and extending it with module like RDFmodule before you can operate on things. I don't understand that logic. It sounds like you have to create your own RDFlib by composing the generic things all the time? AM i right ?

antonkulaga · 2015-08-11T18:55:05Z

Banana-rdf is published, just search for it at maven central

Maatary · 2015-08-11T19:00:57Z

Error:Error while importing SBT project:
...
at scala.Function1$$anonfun$compose$1.apply(Function1.scala:47)
at sbt.$tilde$greater$$anonfun$$u2219$1.apply(TypeFunctions.scala:40)
at sbt.std.Transform$$anon$4.work(System.scala:63)
at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:226)
at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:226)
at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
at sbt.Execute.work(Execute.scala:235)
at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:226)
at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:226)
at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:159)
at sbt.CompletionService$$anon$2.call(CompletionService.scala:28)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
[error] sbt.ResolveException: unresolved dependency: org.w3#rdf_jvm_2.11;0.7: not found
[error] unresolved dependency: org.w3#ntriples_jvm_2.11;0.7: not found
[error] Use 'last' for the full log.

See complete log in /Users/maatary/Library/Logs/IntelliJIdea14/sbt.last.log

Maatary · 2015-08-11T20:07:48Z

I have this weird error with sbt

antonkulaga · 2015-08-11T23:34:08Z

. I don't understand that logic. It sounds like you have to create your own RDFlib by composing the generic things all the time? AM i right ?

You are not. The example with Sesame was given just to explain how banana-rdf works (BTW I updated it a bit https://github.com/banana-rdf/banana-rdf/wiki/Core-concepts )

antonkulaga · 2015-08-11T23:37:41Z

@Maatary the documentaion is a bit outdated, we are at 0.8.x series now. Please, use

libraryDependencies += "org.w3" %% "banana-jena" % "0.8.1"

in case of jena

bblfish · 2015-08-12T07:01:32Z

@antonkulaga that should be on the front page of github README. Someone should propose a pull request for that. Also there should be a pointer to the maven repo, so that people can see what other things were available.

antonkulaga · 2015-08-12T11:07:15Z

@bblfish what do you think about cleaning README and leaving there only a link to wiki? Documentation in several places (readme and wiki) only leads to confusion (IMHO).

Maatary · 2015-08-12T16:06:18Z

@antonkulaga please help a bit further here and i will also try by the same occasion to explain what i meant.

I want to perform some sparql query in my code. I pick Jena as the underlying engine.

If i follow the test suite as it is recommended in the doc for now, I get something like this:

trait SparqlEngineTesterTrait [Rdf <: RDF, M[+_], A] extends BeforeAndAfterAll { self: Suite =>
  val store: A
  val reader: RDFReader[Rdf, Try, RDFXML]
  implicit val ops: RDFOps[Rdf]
  implicit val graphStore: GraphStore[Rdf, M, A]
  implicit val monad:  Monad[M]
  implicit val comonad: Comonad[M]

  val lifecycle: Lifecycle[Rdf, A]

followed by

class SparqlEngineTest[Rdf <: RDF, A](
  val store: A)(implicit
  val reader: RDFReader[Rdf, Try, RDFXML],
  val ops: RDFOps[Rdf],
  val comonad: scalaz.Comonad[scala.util.Try],
  val monad: scalaz.Monad[scala.util.Try],
  val sparqlOps: SparqlOps[Rdf],
  val graphStore: GraphStore[Rdf, Try, A],
  val sparqlEngine: SparqlEngine[Rdf, Try, A],
  val lifecycle: Lifecycle[Rdf, A]
) extends WordSpec with SparqlEngineTesterTrait[Rdf, Try, A] with Matchers with BeforeAndAfterAll with TryValues {

I think this is very complicate and does not help to quickly grasp how to proceed. It also differs a little from the online guide about Sparql Usage (which is easier to understand). In the end i don't know which one to use:

trait SPARQLExampleDependencies
  extends RDFModule
  with RDFOpsModule
  with SparqlOpsModule
  with SparqlHttpModule

trait SPARQLExample extends SPARQLExampleDependencies { self =>

  import ops._
  import sparqlOps._
  import sparqlHttp.sparqlEngineSyntax._

import org.w3.banana.jena.JenaModule

object SPARQLExampleWithJena extends SPARQLExample with JenaModule

What i meant originally, is that, if you want to you banana-rdf, you can't just import something in a class, you have to creating that binding between an the generic abstraction and an implementation.

Is there just a simpler form ?

antonkulaga · 2015-08-12T16:57:42Z

@Maatary could you, please, use

//markdown for your scala code?

when you quote code samples?

Maatary · 2015-08-12T17:35:48Z

Here is what i did and can't get it to work:

import java.net.URL

import org.w3.banana.{SparqlHttpModule, SparqlOpsModule, RDFOpsModule, RDFModule}

/**
 * Created by Daniel Maatari Okouya on 8/12/15.
 *
 */

trait SPARQLExampleDependencies
  extends RDFModule
  with RDFOpsModule
  with SparqlOpsModule
  with SparqlHttpModule

trait SPARQLExample extends SPARQLExampleDependencies { self =>

  import ops._
  import sparqlOps._
  import sparqlHttp.sparqlEngineSyntax._

  def main(args: Array[String]): Unit = {

    /* gets a SparqlEngine out of a Sparql endpoint */

    val endpoint = new URL("http://dbpedia.org/sparql/")

    /* creates a Sparql Select query */

    val query = parseSelect("""
PREFIX ont: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?language WHERE {
 ?language a ont:ProgrammingLanguage .
 ?language ont:influencedBy ?other .
 ?other ont:influencedBy ?language .
} LIMIT 100
                            """).get

    /* executes the query */

    val answers: Rdf#Solutions = endpoint.executeSelect(query).get

    /* iterate through the solutions */

    val languages: Iterator[Rdf#URI] = answers.iterator map { row =>
      /* row is an Rdf#Solution, we can get an Rdf#Node from the variable name */
      /* both the #Rdf#Node projection and the transformation to Rdf#URI can fail in the Try type, hense the flatMap */
      row("language").get.as[Rdf#URI].get
    }

    println(languages.to[List])
  }

}

object SparqlService extends App {

  import org.w3.banana.jena.JenaModule

  object SPARQLExampleWithJena extends SPARQLExample with JenaModule

  SPARQLExampleWithJena.main(null)

}

I get the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.apache.xerces.parsers.AbstractDOMParser.startDocument(Unknown Source)
    at org.apache.xerces.impl.dtd.XMLDTDValidator.startDocument(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl.startEntity(Unknown Source)
    at org.apache.xerces.impl.XMLVersionDetector.startDocumentParsing(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at sun.util.xml.PlatformXmlPropertiesProvider.getLoadingDoc(PlatformXmlPropertiesProvider.java:106)
    at sun.util.xml.PlatformXmlPropertiesProvider.load(PlatformXmlPropertiesProvider.java:78)
    at java.util.Properties$XmlSupport.load(Properties.java:1201)
    at java.util.Properties.loadFromXML(Properties.java:881)
    at com.hp.hpl.jena.util.Metadata.read(Metadata.java:76)
    at com.hp.hpl.jena.util.Metadata.addMetadata(Metadata.java:54)
    at com.hp.hpl.jena.util.Metadata.<init>(Metadata.java:48)
    at com.hp.hpl.jena.JenaRuntime.<clinit>(JenaRuntime.java:34)
    at com.hp.hpl.jena.rdf.model.impl.RDFReaderFImpl.reset(RDFReaderFImpl.java:81)
    at com.hp.hpl.jena.rdf.model.impl.RDFReaderFImpl.<clinit>(RDFReaderFImpl.java:74)
    at com.hp.hpl.jena.rdf.model.impl.ModelCom.<clinit>(ModelCom.java:54)
    at com.hp.hpl.jena.rdf.model.ModelFactory.createDefaultModel(ModelFactory.java:114)
    at org.w3.banana.jena.util.QuerySolution.<init>(QuerySolution.scala:13)
    at org.w3.banana.jena.JenaGraphSparqlEngine.<init>(JenaGraphSparqlEngine.scala:15)
    at org.w3.banana.jena.JenaGraphSparqlEngine$.apply(JenaGraphSparqlEngine.scala:44)
    at org.w3.banana.jena.JenaModule$class.$init$(JenaModule.scala:38)
    at SparqlService$SPARQLExampleWithJena$.<init>(SparqlService.scala:60)
    at SparqlService$SPARQLExampleWithJena$.<clinit>(SparqlService.scala)
    at SparqlService$.delayedEndpoint$SparqlService$1(SparqlService.scala:62)
    at SparqlService$delayedInit$body.apply(SparqlService.scala:56)
    at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
    at scala.App$$anonfun$main$1.apply(App.scala:76)
    at scala.App$$anonfun$main$1.apply(App.scala:76)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:35)
    at scala.App$class.main(App.scala:76)
    at SparqlService$.main(SparqlService.scala:56)
    at SparqlService.main(SparqlService.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: java.lang.ClassNotFoundException: org.w3c.dom.ElementTraversal
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 55 more

Maatary · 2015-08-12T17:41:21Z

I have been able to run the example in itself. The example situated in the misc folder for the sparqlengine usage, but from within the banana-rdf project.

However,

what i want is to be able to modularize my code such that to use it out of your example, but it is not crystal clear to me how should i achieve it.

Beside when i copy paste the example from mist to my project i get the error above. In other, without event the slight modification that i introduce.

Here is my dependency declaration in my build:

"org.w3" %% "banana-jena" % "0.8.1"

Maatary · 2015-08-12T17:53:57Z

I'm using JDK 8, scala 2.11.x
I can't seem to figure out: java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal

Maatary · 2015-08-12T19:17:29Z

I solved my problem by forcing this:

dependencyOverrides += "xml-apis" % "xml-apis" % "1.4.01"

However my original question about modularizing stuff still remain. I will try to follow the example and modularize as i can.

The one from the test suites sounds just too complicate. (I'm talking about instantiating the rdf library not the code inside the examples.)

Maatary · 2015-08-12T19:38:11Z

In term of modularization what i want is to bring in scope a jena-banana-rdf. Then use it in my class.

Your example hard code things in the class that construct the binder. I don't want to do that.

Here is what i tried in my scala workshit:

import java.net.URL

import org.w3.banana.jena.JenaModule
import org.w3.banana.{SparqlHttpModule, SparqlOpsModule, RDFOpsModule, RDFModule}

object SparqlService extends RDFModule with RDFOpsModule with SparqlOpsModule
with SparqlHttpModule with JenaModule

import SparqlService._

import SparqlService.sparqlOps

import SparqlService.sparqlOps._
import SparqlService.sparqlHttp.sparqlEngineSyntax._
import SparqlService.ops._

val endpoint = new URL("http://dbpedia.org/sparql/")

val query = parseSelect("""
PREFIX ont: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?language WHERE {
 ?language a ont:ProgrammingLanguage .
 ?language ont:influencedBy ?other .
 ?other ont:influencedBy ?language .
} LIMIT 100
                        """).get

query.toString

val answers: Rdf#Solutions = endpoint.executeSelect(query).get
/* iterate through the solutions */
val languages: Iterator[Rdf#URI] = answers.iterator map { row =>
  /* row is an Rdf#Solution, we can get an Rdf#Node from the variable name */
  /* both the #Rdf#Node projection and the transformation to Rdf#URI can fail in the Try type, hense the flatMap */
  row("language").get.as[Rdf#URI].get
}

println(languages.to[List])

However i get the following error:

Error:(35, 26) could not find implicit value for parameter fromPG: org.w3.banana.binder.FromPG[org.w3.banana.jena.Jena,com.hp.hpl.jena.graph.Node_URI]
  row("language").get.as[Rdf#URI].get
                        ^

I thought i had imported all the riqured implicit at that point. What am i Missing ?

antonkulaga · 2015-08-12T20:03:10Z

@Maatary actually extending your class from modules is not mandatory, it is possible to work in banana-rdf just by resolving operation (RDFOps, SparqlOps, etc.) classes from Rdf<:RDF type. The examples that are in wiki are old. I think it is possible to provide simpler examples but I am simply very busy this week and do not have time for docs =(

P.S. By the way, you can have scala syntax highlightning for your scala code:

println("it syntax highlighting works!")

println("it syntax highlighting works!")

P.P.S. I also added you to banana-rdf gitter channel

Maatary · 2015-08-12T20:15:22Z

Thank you, i will write on the channel to see if anybody can help with what you say.

Meanwhile, any idea what import i am missing here maybe ?

bblfish · 2015-08-12T20:59:25Z

I'd go for the minimal change to the README for the moment.

Maatary · 2015-08-13T15:36:52Z

is there a way to do a basic http authentication with the sparql engine ?

bblfish · 2015-08-13T15:39:10Z

@Maatary that last question looks like it should be in a different issue.

Maatary · 2015-08-13T15:54:42Z

indeed

antonkulaga · 2015-08-14T10:55:28Z

I'd go for the minimal change to the README for the moment.

@bblfish I've made #295 PR to README

Maatary closed this as completed Aug 12, 2015

Maatary reopened this Aug 12, 2015

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