Examples with DereferenceException org.apache.stanbol.enhancer.engines.dereference.DereferenceException used on opensource projects

Example 1 with DereferenceException

use of org.apache.stanbol.enhancer.engines.dereference.DereferenceException in project stanbol by apache.

the class TrackingDereferencerBase method dereference.

@Override
public final boolean dereference(IRI uri, Graph graph, Lock writeLock, DereferenceContext dc) throws DereferenceException {
    T service = getService();
    if (service == null) {
        throw new DereferenceException(uri, serviceClass.getClass().getSimpleName() + "service is currently not available");
    }
    EntityhubDereferenceContext derefContext = (EntityhubDereferenceContext) dc;
    Representation rep;
    try {
        rep = getRepresentation(service, uri.getUnicodeString(), derefContext.isOfflineMode());
    } catch (EntityhubException e) {
        throw new DereferenceException(uri, e);
    }
    //we need the languages as strings
    final Set<String> langs = derefContext.getLanguages();
    final FieldMapper fieldMapper = derefContext.getFieldMapper();
    final Program<Object> ldpathProgram = derefContext.getProgram();
    if (rep != null) {
        if (fieldMapper == null && ldpathProgram == null && (langs == null || langs.isEmpty())) {
            copyAll(uri, rep, graph, writeLock);
        } else {
            //we need to apply some filters while dereferencing
            if (fieldMapper != null || (langs != null && !langs.isEmpty())) {
                //this considers speficied fields and included languages
                copyMapped(uri, rep, fieldMapper, langs, graph, writeLock);
            }
            if (ldpathProgram != null) {
                //this executes LDPath statements
                copyLdPath(uri, getRdfBackend(service), ldpathProgram, langs, graph, writeLock);
            }
        }
        return true;
    } else {
        return false;
    }
}

Example 2 with DereferenceException

use of org.apache.stanbol.enhancer.engines.dereference.DereferenceException in project stanbol by apache.

the class TrackingDereferencerBase method copyLdPath.

/**
     * Executes the {@link #ldpathProgram} using the parsed URI as context and
     * writes the the results to the parsed ImmutableGraph
     * @param uri the context
     * @param rdfBackend the RdfBackend the LDPath program is executed on
     * @param ldpathProgram The {@link Program} parsed via the dereference context
     * @param langs the set of languages to dereference
     * @param graph the graph to store the results
     * @param writeLock the write lock for the graph
     * @throws DereferenceException on any {@link EntityhubException} while
     * executing the LDPath program
     */
private void copyLdPath(IRI uri, RDFBackend<Object> rdfBackend, Program<Object> ldpathProgram, Set<String> langs, Graph graph, Lock writeLock) throws DereferenceException {
    //A RdfReference needs to be used as context
    RdfReference context = valueFactory.createReference(uri);
    //create the representation that stores results in an intermediate
    //graph (we do not want partial results on an error
    Graph ldPathResults = new SimpleGraph();
    RdfRepresentation result = valueFactory.createRdfRepresentation(uri, ldPathResults);
    //execute the LDPath Program and write results to the RDF ImmutableGraph
    try {
        for (org.apache.marmotta.ldpath.model.fields.FieldMapping<?, Object> mapping : ldpathProgram.getFields()) {
            Collection<?> values;
            try {
                values = mapping.getValues(rdfBackend, context);
            } catch (RuntimeException e) {
                throw new DereferenceException(uri, e);
            }
            if (values != null && !values.isEmpty()) {
                String fieldName = mapping.getFieldName();
                if (langs == null || langs.isEmpty()) {
                    result.add(fieldName, values);
                } else {
                    //filter for languages
                    for (Object value : values) {
                        if ((!(value instanceof Text)) || langs.contains(((Text) value).getLanguage())) {
                            result.add(fieldName, value);
                        }
                    //else text with filtered language ... do not add
                    }
                }
            }
        }
    } catch (EntityhubException e) {
        throw new DereferenceException(uri, e);
    }
    if (log.isTraceEnabled()) {
        log.trace("dereferenced via LDPath {}", ModelUtils.getRepresentationInfo(result));
    }
    if (!ldPathResults.isEmpty()) {
        //copy the results
        writeLock.lock();
        try {
            graph.addAll(ldPathResults);
        } finally {
            writeLock.unlock();
        }
    }
}