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

Example 1 with EntityhubLDPath

use of org.apache.stanbol.entityhub.ldpath.EntityhubLDPath in project stanbol by apache.

the class TrackingDereferencerBase method setLdPath.

/**
     * Setter for the LDPath program used for dereferencing Entities
     * @param ldpathProgramStr the LDPath program as String
     * @throws ConfigurationException if parsing the LDPath program fails
     */
public void setLdPath(String ldpathProgramStr) throws ConfigurationException {
    if (ldpathProgramStr == null || StringUtils.isBlank(ldpathProgramStr)) {
        ldpathProgram = null;
    } else {
        //validate the parsed LDPath program
        //when this method is called the real RDFBackend will not be available.
        //however we would like to parse/validate the parsed LDPath program
        //So we will create a pseudo RDFBackend sufficient to be used with the
        //parser
        final RDFBackend<Object> parseBackend = new ParseBackend<T>(valueFactory);
        //NOTE: calling execute(..) an this parseLdPath or even the 
        //ldpathProgram will result in UnsupportedOperationException
        //but parsing is OK
        EntityhubLDPath parseLdPath = new EntityhubLDPath(parseBackend, valueFactory);
        try {
            ldpathProgram = parseLdPath.parseProgram(new StringReader(ldpathProgramStr));
        } catch (LDPathParseException e) {
            log.error("Unable to parse LDPath pogram: \n {}", ldpathProgramStr);
            throw new ConfigurationException(DereferenceConstants.DEREFERENCE_ENTITIES_LDPATH, "Unable to parse configured LDPath program ", e);
        }
        //finally validate if all mappings of the programm do use a URI as key
        for (org.apache.marmotta.ldpath.model.fields.FieldMapping<?, Object> mapping : ldpathProgram.getFields()) {
            try {
                new URI(mapping.getFieldName());
            } catch (URISyntaxException e) {
                throw new ConfigurationException(DereferenceConstants.DEREFERENCE_ENTITIES_LDPATH, "Parsed LDPath MUST use valid URIs as field names (invalid field name: '" + mapping.getFieldName() + "' | selector: '" + mapping.getSelector().getPathExpression(parseBackend) + "')!");
            }
        }
    }
}

Example 2 with EntityhubLDPath

use of org.apache.stanbol.entityhub.ldpath.EntityhubLDPath 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();
}

Example 3 with EntityhubLDPath

use of org.apache.stanbol.entityhub.ldpath.EntityhubLDPath in project stanbol by apache.

the class ReferencedSiteRootResource 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(Site site, FieldQuery query, String ldpathProgramString, MediaType mediaType, HttpHeaders headers) {
    QueryResultList<Representation> result;
    ValueFactory vf = new RdfValueFactory(new IndexedGraph());
    SiteBackend backend = new SiteBackend(site, vf);
    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 Query:");
        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 parsed Query!", e);
        return Response.status(Status.BAD_REQUEST).entity(e.getMessage()).header(HttpHeaders.ACCEPT, mediaType).build();
    }
    //2. execute the query
    Iterator<Representation> resultIt;
    try {
        // we need to adapt from Entity to Representation
        resultIt = new AdaptingIterator<Entity, Representation>(site.findEntities(query).iterator(), new AdaptingIterator.Adapter<Entity, Representation>() {

            @Override
            public Representation adapt(Entity value, Class<Representation> type) {
                return value.getRepresentation();
            }
        }, Representation.class);
    } catch (SiteException e) {
        String message = String.format("Unable to Query Site '%s' (message: %s)", site.getId(), e.getMessage());
        log.error(message, e);
        return Response.status(Status.INTERNAL_SERVER_ERROR).entity(message).header(HttpHeaders.ACCEPT, mediaType).build();
    }
    //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();
}

Example 4 with EntityhubLDPath

use of org.apache.stanbol.entityhub.ldpath.EntityhubLDPath in project stanbol by apache.

the class EntityhubRootResource 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(Entityhub entityhub, FieldQuery query, String ldpathProgramString, MediaType mediaType, HttpHeaders headers) {
    QueryResultList<Representation> result;
    ValueFactory vf = new RdfValueFactory(new IndexedGraph());
    EntityhubBackend backend = new EntityhubBackend(entityhub);
    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 Query:");
        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 parsed Query!", e);
        return Response.status(Status.BAD_REQUEST).entity(e.getMessage()).header(HttpHeaders.ACCEPT, mediaType).build();
    }
    //2. execute the query
    Iterator<Representation> resultIt;
    try {
        // go directly to the yard and query there for Representations
        resultIt = entityhub.getYard().findRepresentation(query).iterator();
    } catch (EntityhubException e) {
        String message = String.format("Exception while performing the " + "FieldQuery on the EntityHub (message: %s)", e.getMessage());
        log.error(message, e);
        return Response.status(Status.INTERNAL_SERVER_ERROR).entity(message).header(HttpHeaders.ACCEPT, mediaType).build();
    }
    //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();
}

Example 5 with EntityhubLDPath

use of org.apache.stanbol.entityhub.ldpath.EntityhubLDPath in project stanbol by apache.

the class LdpathPostProcessor method initialise.

@Override
public void initialise() {
    //override the ldpath instance used for the initialisation with
    //the one using the IndexingDestination
    //this is OK, because parsing ldpath programs anyway does only need
    //the "value factory" role of the RDFBackend and does not actually
    //access any data.
    Yard yard = indexingConfig.getIndexingDestination().getYard();
    YardBackend backend = new YardBackend(yard);
    this.ldPath = new EntityhubLDPath(backend, yard.getValueFactory());
}