Examples with SiteManagerBackend org.apache.stanbol.entityhub.ldpath.backend.SiteManagerBackend used on opensource projects

Example 1 with SiteManagerBackend

use of org.apache.stanbol.entityhub.ldpath.backend.SiteManagerBackend in project stanbol by apache.

the class SiteManagerRootResource method executeLDPathQuery.

/**
 * Execute a Query that uses LDPath to process results.
 * @param query the query
 * @param mediaType the mediaType for the response
 * @param headers the http headers of the request
 * @return the response
 */
private Response executeLDPathQuery(SiteManager manager, FieldQuery query, String ldpathProgramString, MediaType mediaType, HttpHeaders headers) {
    QueryResultList<Representation> result;
    ValueFactory vf = new RdfValueFactory(new IndexedGraph());
    SiteManagerBackend backend = new SiteManagerBackend(manager);
    EntityhubLDPath ldPath = new EntityhubLDPath(backend, vf);
    // copy the selected fields, because we might need to delete some during
    // the preparation phase
    Set<String> selectedFields = new HashSet<String>(query.getSelectedFields());
    // first prepare (only execute the query if the parameters are valid)
    Program<Object> program;
    try {
        program = prepareQueryLDPathProgram(ldpathProgramString, selectedFields, backend, ldPath);
    } catch (LDPathParseException e) {
        log.warn("Unable to parse LDPath program used as select for a Query to the '/sites' endpoint:");
        log.warn("FieldQuery: \n {}", query);
        log.warn("LDPath: \n {}", ((LDPathSelect) query).getLDPathSelect());
        log.warn("Exception:", e);
        return Response.status(Status.BAD_REQUEST).entity(("Unable to parse LDPath program (Messages: " + getLDPathParseExceptionMessage(e) + ")!\n")).header(HttpHeaders.ACCEPT, mediaType).build();
    } catch (IllegalStateException e) {
        log.warn("parsed LDPath program is not compatible with the Query " + "parsed to the '/sites' endpoint!", e);
        return Response.status(Status.BAD_REQUEST).entity(e.getMessage()).header(HttpHeaders.ACCEPT, mediaType).build();
    }
    // 2. execute the query
    // we need to adapt from Entity to Representation
    // TODO: should we add the metadata to the result?
    Iterator<Representation> resultIt = new AdaptingIterator<Entity, Representation>(manager.findEntities(query).iterator(), new AdaptingIterator.Adapter<Entity, Representation>() {

        @Override
        public Representation adapt(Entity value, Class<Representation> type) {
            return value.getRepresentation();
        }
    }, Representation.class);
    // process the results
    Collection<Representation> transformedResults = transformQueryResults(resultIt, program, selectedFields, ldPath, backend, vf);
    result = new QueryResultListImpl<Representation>(query, transformedResults, Representation.class);
    ResponseBuilder rb = Response.ok(result);
    rb.header(HttpHeaders.CONTENT_TYPE, mediaType + "; charset=utf-8");
    // addCORSOrigin(servletContext, rb, headers);
    return rb.build();
}