com.weblyzard.sparql:streaming-sparql

Cross-server SPARQL query library with support for incremental, streaming result processing.

License	The Apache License, Version 2.0
GroupId	com.weblyzard.sparql
ArtifactId	streaming-sparql
Last Version	0.0.7.2
Release Date	Apr 1, 2021
Type	jar
Description	Cross-server SPARQL query library with support for incremental, streaming result processing.
Project Organization	webLyzard technology
Source Code Management	https://github.com/weblyzard/streaming-sparql/tree/master/streaming-sparql

Download streaming-sparql

Filename	Size
streaming-sparql-0.0.7.2.pom
streaming-sparql-0.0.7.2.jar	12 MB
streaming-sparql-0.0.7.2-sources.jar	5 KB
streaming-sparql-0.0.7.2-javadoc.jar	42 KB

How to add to project

Apache Maven

<!-- https://jarcasting.com/artifacts/com.weblyzard.sparql/streaming-sparql/ -->
<dependency>
    <groupId>com.weblyzard.sparql</groupId>
    <artifactId>streaming-sparql</artifactId>
    <version>0.0.7.2</version>
</dependency>

Gradle Groovy

// https://jarcasting.com/artifacts/com.weblyzard.sparql/streaming-sparql/
implementation 'com.weblyzard.sparql:streaming-sparql:0.0.7.2'

Gradle Kotlin

// https://jarcasting.com/artifacts/com.weblyzard.sparql/streaming-sparql/
implementation ("com.weblyzard.sparql:streaming-sparql:0.0.7.2")

Apache Buildr

'com.weblyzard.sparql:streaming-sparql:jar:0.0.7.2'

Apache Ivy

<dependency org="com.weblyzard.sparql" name="streaming-sparql" rev="0.0.7.2">
  <artifact name="streaming-sparql" type="jar" />
</dependency>

Groovy Grape

@Grapes(
@Grab(group='com.weblyzard.sparql', module='streaming-sparql', version='0.0.7.2')
)

Scala SBT

libraryDependencies += "com.weblyzard.sparql" % "streaming-sparql" % "0.0.7.2"

Leiningen

[com.weblyzard.sparql/streaming-sparql "0.0.7.2"]

Dependencies

compile (2)

Group / Artifact	Type	Version
org.apache.jena : jena-arq	jar	3.10.0
org.slf4j : slf4j-api	jar	1.7.25

provided (1)

Group / Artifact	Type	Version
org.projectlombok : lombok	jar	1.18.8

test (5)

Group / Artifact	Type	Version
com.google.guava : guava	jar	30.1.1-jre
com.google.code.gson : gson	jar	2.8.5
junit : junit	jar	4.13.1
io.github.stephenc.docker : junit-docker-rule	jar	0.5.2
org.apache.logging.log4j : log4j-slf4j-impl	jar	2.11.1

Project Modules

There are no modules declared in this project.

Streaming SPARQL

Provides a robust, incremental processing of streaming results received from SPARQL servers. The StreamingResultSet iterator yields results as they are received from the server.

Javadoc

http://javadoc.io/doc/com.weblyzard.sparql/streaming-sparql/

Example code:

try (StreamingResultSet s = StreamingQueryExecutor.getResultSet("http://dbpedia.org/sparql", "SELECT ?s ?p ?o WHERE { ?s ?p ?o. } LIMIT 5")) {
    while (s.hasNext()) {
        System.out.println("Tupel " + s.getRowNumber() + ": " + s.next())
    }
}

Command line client

Streaming SPARQL also provides a command line client for testing queries.

Usage

java -jar ./streaming-client-0.0.7-SNAPSHOT.jar
QueryEntitites [URL] [Query]
  URL   ... URL to the linked data repository
  Query ... The query to perform on the server

Example

java -jar ./streaming-client-0.0.7-SNAPSHOT.jar http://localhost:8080/rdf4j-sesame/test "SELECT ?s ?p ?o WHERE { ?s ?p ?o. } LIMIT 5"

Background

We have been using Fuseki and RDF4j together with comprehensive result sets (> 100 Mio. tuple) which lead to instabilities with the native libraries that have been extremely difficult to debug.

Example error messages on the server site have been:

[2017-05-04 19:50:14] Fuseki     WARN  [1450] Runtime IO Exception (client left?) RC = 500 : org.eclipse.jetty.io.EofException      
org.apache.jena.atlas.RuntimeIOException: org.eclipse.jetty.io.EofException                                                         

[2017-05-04 19:50:14] Fuseki    WARN  (HttpChannel.java:468) (and one from ServletHandler.java:631):
java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 30001/30000 m

These problems triggered the development of Streaming SPARQL which has proven to be very robust - even for queries that take more than one hour to process and transfer multiple gigabytes of results. (Note: you will need to call getResultSet with a higher timeout to prevent TimeoutExceptions on the server).

Compatiblity

Streaming SPARQL is known to work with Jena, OpenRDF, RDF4j and Virtuoso.

Changelog

Please refer to the release page.

webLyzard technology

Versions

Version
0.0.7.2 Apr 1, 2021
0.0.7.1 Jan 14, 2019
0.0.7 Jan 12, 2019
0.0.3 Sep 28, 2017
0.0.2 Aug 26, 2017