jena-proxy

Apache Jena Dataset Proxy implementations for remote SPARQL and RDFLink endpoints.

Overview

jena-proxy provides Proxy pattern implementations for Apache Jena DatasetGraph that transparently forward operations to remote endpoints:

• jena-proxy-dataset-sparql: DatasetGraph over SPARQL Query/Update protocol
• jena-proxy-dataset-rdflink: DatasetGraph over Apache Jena RDFLink

These modules allow you to work with remote datasets as if they were local, while all SPARQL operations are executed against remote endpoints.

Features

• Transparent remote access: Use standard Jena DatasetGraph API
• SPARQL protocol support: Query and update via HTTP SPARQL endpoints
• RDFLink integration: Use Apache Jena's modern RDFLink interface
• Configurable transactions: Enable/disable transactional support
• HTTP authentication: Basic authentication support
• Jena assembler support: Configure via Turtle configuration files

Modules

jena-proxy-dataset-sparql

A DatasetGraph implementation that forwards all operations to a remote endpoint via the SPARQL Query/Update protocol.

Key classes:

• DatasetGraphSparql - Base implementation
• DsgSparqlExecutor - SPARQL execution strategy
• DsgSparqlExecutorImpl - Default executor

jena-proxy-dataset-rdflink

A DatasetGraph implementation that uses Apache Jena's RDFLink interface to connect to remote endpoints.

Key classes:

• DatasetGraphOverRDFLink - Main implementation
• DatasetAssemblerHTTP - Jena assembler for HTTP configuration
• JenaPluginDatasetGraphOverRDFLink - Auto-registration plugin

Quick Start

Maven Dependency

<dependency>
    <groupId>org.aksw.jena.proxy</groupId>
    <artifactId>jena-proxy-dataset-rdflink</artifactId>
    <version>0.7.0</version>
</dependency>

Programmatic API

import org.aksw.jena.rdflink.dataset.DatasetGraphOverRDFLink;
import org.apache.jena.rdflink.RDFLink;
import org.apache.jena.rdflink.RDFLinkHTTP;
import org.apache.jena.sparql.core.DatasetGraph;

// Create an RDFLink to a remote endpoint
RDFLink link = RDFLinkHTTP.newBuilder()
    .queryEndpoint("http://localhost:3030/dataset/query")
    .updateEndpoint("http://localhost:3030/dataset/update")
    .gspEndpoint("http://localhost:3030/dataset/data")
    .build();

// Create a DatasetGraph proxy
DatasetGraph dsg = DatasetGraphOverRDFLink.create(() -> link);

// Use it like a local dataset
dsg.getDefaultGraph().contains(...);

Jena Assembler Configuration

@prefix dsg: <https://w3id.org/aksw/jena/dataset#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

<#dataset> a dsg:DatasetHTTP ;
    dsg:destination "http://localhost:3030/dataset" ;
    dsg:auth [
        dsg:user "username" ;
        dsg:pass "password" ;
    ] .

Build

# Clone the repository
git clone https://github.com/Scaseco/jena-proxy.git
cd jena-proxy-parent

# Build with Maven
mvn clean install

# Run tests
mvn test

Requirements

• Java 21 or later
• Maven 3.8+
• Apache Jena 6.2.0+

License

This project is licensed under the Apache License 2.0.

Project Information

• GitHub: https://github.com/Scaseco/jena-proxy
• Issues: https://github.com/Scaseco/jena-proxy/issues
• Maven Central: https://search.maven.org/search?q=g:org.aksw.jena.proxy