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Questions tagged [arq]

A query engine for Jena that supports the SPARQL RDF Query language

A query engine for Jena that supports the SPARQL RDF Query language.

Features

  • Standard SPARQL
  • Free text search via Lucene
  • SPARQL/Update
  • Access and extension of the SPARQL algebra
  • Support for custom filter functions
  • Property functions for custom processing of semantic relationships
  • Aggregation, GROUP BY and assignment as SPARQL extensions
  • Support for federated query
  • Support for extension to other storage systems
  • Client-support for remote access to any SPARQL endpoint

Documentation

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How to Serialize ARQ Algebra as ASK/CONSTRUCT SPARQL Query?

My intention is to Parse a SPARQL query to the ARQ Algebra. Get some work done. Parse the ARQ Algebra back to SPARQL query. Approach below seems to work as expected for SELECT queries, but fails for ASK and CONSTRUCT queries. I will highly value…
RedCrusaderJr
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How to customize Jena ARQ query engine to add additional triple pattern

Given the following triples describe Forklift1 location at the different times: :forklift1 :location :station1, :dockdoor1; :9305fc5f-d43d :station1; :a4e9-2bcd5b97 :dockdoor1; . :9305fc5f-d43d a :location; :createdDate…
Tony
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Jena Fuseki: Adding temporary triples to execution context during SPARQL-query with property functions

I've been following the ARQ guide on Property Functions. The section on Graph Operations concludes with "New Triples or Graphs can therefore be created as part of the Property Function" and I've been hoping to use this as a means to add triples to…
InSilico
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Out of order packets in Ad-hoc Network real-time data transmission using UDP with a costume ARQ application

I'm facing a misunderstanding here. I have an application based on UDP for Automatic repeat request mechanism. The idea is to transmit real-time data with a mechanism of retransmission and reordering of received packets ( temporary buffer to manage…
Med Nimou
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Apache Jena Aggregate multiple expressions

For the following data.ttl file: A SAVINGS_1 200 A SAVINGS_2 300 A SAVINGS_3 370 A EMAIL emailidone B SAVINGS_1 400 B SAVINGS_2 300 B SAVINGS_3 100 B EMAIL emailidtwo C SAVINGS_1 200 C SAVINGS_2 600 The query: SELECT ?NAME ?SAVINGS_1_VALUE…
Adrika
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Optimal Filter Placement in SPARQL Queries

One of the optimizations performed by JenaARQ is to: "Place filters close to where their dependency variables are defined". This causes the following Query Plan: (filter (exprlist (|| (|| (isIRI ?Y) (isBlank ?Y)) (!= (datatype ?Y)…
Elton Soares
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Add prefixes to queries in SPARQL

I am running the following query using the apache jena sparql library in java: String queryString ="SELECT ?startTime ?endTime " + "WHERE { " + "?y rdfs:label \"Processor execution GETIMAGE\" . "+ …
Elias
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SPARQL ElementPathBlock

In am trying to retrieve the triples of a SPARQL expression involved in the OPTIONAL and NON OPTIONAL part of the query, separately. I used the API ARQ Jena visitor but neither ElementPathBlock nor ElementGroup nor ElementOptional are enough.…
Jesús Almendros
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SPARQL queries with ARQ on Apache Jena

I am encountering a problem with my java application. I'm trying to proceed requests on a Fuseki server to get response from an ontology loaded on it. On my fifth request, the server block and doesn't return any response and sometimes i get this…
j_schneider
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Is there a method to get the URIs from a JENA ARQ Query?

import org.apache.jena.query.Query; public myClass{ public static void myMethod(Query querySparQL) { List A = querySparQL.getGraphURIs(); List B = querySparQL.getNamedGraphURIs(); List C =…
tremendows
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com.hp.hpl.jena.rdf.model.Literal and com.hp.hpl.jena.rdf.model.ResourceFactory not present in 9.2.3 jar or other recent jars?

I added the jena arq 2.9.3 jar file to my code to be able to run sparql queries for DBpedia but it says that the literal and resource factory classes are not present. Do I need to add another version of the jar file or do I need to make changes to…
serendipity
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Scala Sparql query with Apache Jena

I am trying to build a sparql query in scala. I have issues using the apache arq library which is meant for java. The dependencies seem to be all fine but Intellij cannot resolve the ParameterizedSparqlString constructor and resulting the…
Becher
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Getting the value of a RDF predicate when it points to a resource

I want to get an object that is a resource (see "hasAgentWithRole" predicate below). The document (simplified to illustrate my problem):
Anthony
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Jena ARQ update or insert using Fuseki?

What is the difference between "update" and "insert" in Jena ARQ documentation when using FUseki? For example, if I need to add to a Fuseki database (or graph) a simple statement, should I use UpdateExecutionFactory.createRemote method or ARQ -…
Leandro
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ARQ query for blank node

I am working on RDF query language. So, I have installed Apache Jena. RDF data is given below: @prefix foaf: . _:a foaf:name "Alice" . _:b foaf:name "Ashish" . And ARQ query is: PREFIX foaf: …
Abhishek Raj
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