Ontology-drive Linked Data processor and server for SPARQL backends. Apache License.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Failed to load latest commit information.
src
.gitignore
Dockerfile
LICENSE
README.md
pom.xml
stress-test.jmx

README.md

AtomGraph Processor is a Java backend for building declarative, read-write Linked Data applications. If you have a triplestore with RDF data that you want to serve Linked Data from, or write RDF to over a RESTful HTTP interface, AtomGraph Processor is the only component you need.

What AtomGraph Processor provides for users as out-of-the-box generic features:

  • declarative control of published and accepted data using URI and SPARQL templates
  • pagination on container resources, with ordering by property columns
  • control of RDF input quality with SPARQL-based constraints
  • SPARQL endpoint and Graph Store Protocol endpoint
  • HTTP content negotiation and caching
  • a separate RDF resource for every application state, following the HATEOAS principle

AtomGraph's direct use of semantic technologies results in extemely extensible and flexible design and leads the way towards declarative Web development. You can forget all about broken hyperlinks and concentrate on building great apps on quality data. For more details, see articles and presentations about AtomGraph.

For a compatible frontend framework for end-user applications, see AtomGraph Web-Client. The Client extends Processor with RDF rendering and form-based input functionality.

Getting started

For full documentation, see the wiki index.

Maven

AtomGraph artifacts graphity-processor and graphity-core are released on Maven under the org.graphity group ID.

You should normally choose AtomGraph Web-Client as it includes both XSLT and Linked Data functionality, making it useful for end-user as well as server applications. However, if you do not need XSLT and dependency on Saxon or want to use Client and Processor in a client-server setup, you can choose graphity-processor. Dependencies to other AtomGraph artifacts will be resolved automagically during the Maven build processs.

    <dependency>
        <groupId>com.atomgraph</groupId>
        <artifactId>processor</artifactId>
        <version>1.1.3</version>
    </dependency>        

See more about installation.

No permanent storage!

AtomGraph Processor does not include permanent RDF storage. By default it is configured to read the dataset from a file, therefore creating/updating data will have no effect.

In order to store data permanently, you need to set up a triplestore and configure the webapp with its SPARQL endpoint. For open-source, we recommend trying Jena's TDB; for commercial, see Dydra.

Demonstration

Here's the Linked Data output of the root resource description when AtomGraph Processor is run as a standalone webapp (for brevity, all URIs are relativized against the webapp's base URI):

@prefix sioc:  <http://rdfs.org/sioc/ns#> .
@prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#> .
@prefix foaf:  <http://xmlns.com/foaf/0.1/> .
@prefix dct:   <http://purl.org/dc/terms/> .
@prefix xsd:   <http://www.w3.org/2001/XMLSchema#> .
@prefix gc:    <http://atomgraph.com/ns/client#> .
@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix void:  <http://rdfs.org/ns/void#> .
@prefix ldt:   <https://www.w3.org/ns/ldt#> .

# services

<sparql>
        a                   ldt:SPARQLEndpoint ;
        dct:title           "SPARQL endpoint" ;
        sioc:has_space      <> .

<service>
        a                   ldt:GraphStore ;
        dct:title           "Graph Store Protocol endpoint" ;
        sioc:has_space      <> .

# root container

<>
        a                   ldt:Container ;
        rdfs:seeAlso        <sparql> , <http://atomgraph.com> ;
        dct:description     "Generic Linked Data processor" ;
        dct:title           "AtomGraph Processor" ;
        foaf:maker          <http://atomgraph.com/#company> .

# child containers

<ontologies/>
        a                   ldt:Container ;
        ldt:slug            "ontologies" ;
        dct:title           "Ontologies" ;
        sioc:has_parent     <> .

<queries/>
        a                   ldt:Container ;
        ldt:slug            "queries" ;
        dct:title           "Queries" ;
        sioc:has_parent     <> .

<templates/>
        a                   ldt:Container ;
        ldt:slug            "templates" ;
        dct:title           "Templates" ;
        sioc:has_parent     <> .

# page

<?offset=0&limit=20>
        a                   ldt:Page ;
        ldt:limit            "20"^^xsd:long ;
        ldt:offset           "0"^^xsd:long ;
        ldt:pageOf           <> ;
        <http://www.w3.org/1999/xhtml/vocab#next>
                            <?offset=20&limit=20> .

Support

Please report issues if you've encountered a bug or have a feature request.

Commercial AtomGraph consulting, development, and support are available from AtomGraph.

Community

Please join the W3C Declarative Linked Data Apps Community Group to discuss and develop AtomGraph and declarative Linked Data architecture in general.