SD.java

/*******************************************************************************
 * Copyright (c) 2015 Eclipse RDF4J contributors, Aduna, and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Distribution License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *******************************************************************************/
package org.eclipse.rdf4j.model.vocabulary;

import org.eclipse.rdf4j.model.IRI;
import org.eclipse.rdf4j.model.Namespace;

/**
 * Namespace Sparql-service-description. Prefix: {@code <http://www.w3.org/ns/sparql-service-description#>}
 *
 * @author Peter Ansell
 * @see <a href="http://www.w3.org/TR/sparql11-service-description/">SPARQL 1.1 Service Description</a>
 */
public class SD {

	/**
	 * {@code http://www.w3.org/ns/sparql-service-description#}
	 */
	public static final String NAMESPACE = "http://www.w3.org/ns/sparql-service-description#";

	/**
	 * {@code sd}
	 */
	public static final String PREFIX = "sd";

	/**
	 * An immutable {@link Namespace} constant that represents the SPARQL Service Description namespace.
	 */
	public static final Namespace NS = Vocabularies.createNamespace(PREFIX, NAMESPACE);

	/**
	 * Aggregate
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Aggregate}.
	 * <p>
	 * An instance of sd:Aggregate represents an aggregate that may be used in a SPARQL aggregate query (for instance in
	 * a HAVING clause or SELECT expression) besides the standard list of supported aggregates COUNT, SUM, MIN, MAX,
	 * AVG, GROUP_CONCAT, and SAMPLE.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Aggregate">Aggregate</a>
	 */
	public static final IRI AGGREGATE;

	/**
	 * available graph descriptions
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#availableGraphs}.
	 * <p>
	 * Relates an instance of sd:Service to a description of the graphs which are allowed in the construction of a
	 * dataset either via the SPARQL Protocol, with FROM/FROM NAMED clauses in a query, or with USING/USING NAMED in an
	 * update request, if the service limits the scope of dataset construction.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#availableGraphs">availableGraphs</a>
	 */
	public static final IRI AVAILBLE_GRAPHS;

	/**
	 * Basic Federated Query
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#BasicFederatedQuery}.
	 * <p>
	 * sd:BasicFederatedQuery, when used as the object of the sd:feature property, indicates that the SPARQL service
	 * supports basic federated query using the SERVICE keyword as defined by SPARQL 1.1 Federation Extensions.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#BasicFederatedQuery">BasicFederatedQuery </a>
	 */
	public static final IRI BASIC_FEDERATED_QUERY;

	/**
	 * Dataset
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Dataset}.
	 * <p>
	 * An instance of sd:Dataset represents a RDF Dataset comprised of a default graph and zero or more named graphs.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Dataset">Dataset</a>
	 */
	public static final IRI DATASET;

	/**
	 * default dataset description
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#defaultDataset}.
	 * <p>
	 * Relates an instance of sd:Service to a description of the default dataset available when no explicit dataset is
	 * specified in the query, update request or via protocol parameters.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#defaultDataset">defaultDataset</a>
	 */
	public static final IRI DEFAULT_DATASET;

	/**
	 * default entailment regime
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#defaultEntailmentRegime}.
	 * <p>
	 * Relates an instance of sd:Service with a resource representing an entailment regime used for basic graph pattern
	 * matching. This property is intended for use when a single entailment regime by default applies to all graphs in
	 * the default dataset of the service. In situations where a different entailment regime applies to a specific graph
	 * in the dataset, the sd:entailmentRegime property should be used to indicate this fact in the description of that
	 * graph.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#defaultEntailmentRegime">
	 *      defaultEntailmentRegime</a>
	 */
	public static final IRI DEFAULT_ENTAILMENT_REGIME;

	/**
	 * default graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#defaultGraph}.
	 * <p>
	 * Relates an instance of sd:Dataset to the description of its default graph.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#defaultGraph">defaultGraph</a>
	 */
	public static final IRI DEFAULT_GRAPH;

	/**
	 * default supported entailment profile
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#defaultSupportedEntailmentProfile}.
	 * <p>
	 * Relates an instance of sd:Service with a resource representing a supported profile of the default entailment
	 * regime (as declared by sd:defaultEntailmentRegime).
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#defaultSupportedEntailmentProfile">
	 *      defaultSupportedEntailmentProfile</a>
	 */
	public static final IRI DEFAULT_SUPPORTED_ENTAILMENT_PROFILE;

	/**
	 * Dereferences URIs
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#DereferencesURIs}.
	 * <p>
	 * sd:DereferencesURIs, when used as the object of the sd:feature property, indicates that a SPARQL service will
	 * dereference URIs used in FROM/FROM NAMED and USING/USING NAMED clauses and use the resulting RDF in the dataset
	 * during query evaluation.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#DereferencesURIs">DereferencesURIs</a>
	 */
	public static final IRI DEREFERENCES_URIS;

	/**
	 * Empty Graphs
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#EmptyGraphs}.
	 * <p>
	 * sd:EmptyGraphs, when used as the object of the sd:feature property, indicates that the underlying graph store
	 * supports empty graphs. A graph store that supports empty graphs MUST NOT remove graphs that are left empty after
	 * triples are removed from them.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#EmptyGraphs">EmptyGraphs</a>
	 */
	public static final IRI EMPTY_GRAPHS;

	/**
	 * endpoint
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#endpoint}.
	 * <p>
	 * The SPARQL endpoint of an sd:Service that implements the SPARQL Protocol service. The object of the sd:endpoint
	 * property is an IRI.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#endpoint">endpoint</a>
	 */
	public static final IRI ENDPOINT;

	/**
	 * Entailment Profile
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#EntailmentProfile}.
	 * <p>
	 * An instance of sd:EntailmentProfile represents a profile of an entailment regime. An entailment profile MAY
	 * impose restrictions on what constitutes valid RDF with respect to entailment.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#EntailmentProfile">EntailmentProfile</a>
	 */
	public static final IRI ENTAILMENT_PROFILE;

	/**
	 * Entailment Regime
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#EntailmentRegime}.
	 * <p>
	 * An instance of sd:EntailmentRegime represents an entailment regime used in basic graph pattern matching (as
	 * described by SPARQL 1.1 Query Language).
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#EntailmentRegime">EntailmentRegime</a>
	 */
	public static final IRI ENTAILMENT_REGIME_CLASS;

	/**
	 * entailment regime
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#entailmentRegime}.
	 * <p>
	 * Relates a named graph description with a resource representing an entailment regime used for basic graph pattern
	 * matching over that graph.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#entailmentRegime">entailmentRegime</a>
	 */
	public static final IRI ENTAILMENT_REGIME_PROPERTY;

	/**
	 * extension aggregate
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#extensionAggregate}.
	 * <p>
	 * Relates an instance of sd:Service to an aggregate that may be used in a SPARQL aggregate query (for instance in a
	 * HAVING clause or SELECT expression) besides the standard list of supported aggregates COUNT, SUM, MIN, MAX, AVG,
	 * GROUP_CONCAT, and SAMPLE
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#extensionAggregate">extensionAggregate </a>
	 */
	public static final IRI EXTENSION_AGGREGATE;

	/**
	 * extension function
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#extensionFunction}.
	 * <p>
	 * Relates an instance of sd:Service to a function that may be used in a SPARQL SELECT expression or a FILTER,
	 * HAVING, GROUP BY, ORDER BY, or BIND clause.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#extensionFunction">extensionFunction</a>
	 */
	public static final IRI EXTENSION_FUNCTION;

	/**
	 * Feature
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Feature}.
	 * <p>
	 * An instance of sd:Feature represents a feature of a SPARQL service. Specific types of features include functions,
	 * aggregates, languages, and entailment regimes and profiles. This document defines five instances of sd:Feature:
	 * sd:DereferencesURIs, sd:UnionDefaultGraph, sd:RequiresDataset, sd:EmptyGraphs, and sd:BasicFederatedQuery.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Feature">Feature</a>
	 */
	public static final IRI FEATURE_CLASS;

	/**
	 * feature
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#feature}.
	 * <p>
	 * Relates an instance of sd:Service with a resource representing a supported feature.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#feature">feature</a>
	 */
	public static final IRI FEATURE_PROPERTY;

	/**
	 * Function
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Function}.
	 * <p>
	 * An instance of sd:Function represents a function that may be used in a SPARQL SELECT expression or a FILTER,
	 * HAVING, GROUP BY, ORDER BY, or BIND clause.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Function">Function</a>
	 */
	public static final IRI FUNCTION;

	/**
	 * graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#graph}.
	 * <p>
	 * Relates a named graph to its graph description.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#graph">graph</a>
	 */
	public static final IRI GRAPH_PROPERTY;

	/**
	 * Graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Graph}.
	 * <p>
	 * An instance of sd:Graph represents the description of an RDF graph.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Graph">Graph</a>
	 */
	public static final IRI GRAPH_CLASS;

	/**
	 * Graph Collection
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#GraphCollection}.
	 * <p>
	 * An instance of sd:GraphCollection represents a collection of zero or more named graph descriptions. Each named
	 * graph description belonging to an sd:GraphCollection MUST be linked with the sd:namedGraph predicate.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#GraphCollection">GraphCollection</a>
	 */
	public static final IRI GRAPH_COLLECTION;

	/**
	 * input format
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#inputFormat}.
	 * <p>
	 * Relates an instance of sd:Service to a format that is supported for parsing RDF input; for example, via a SPARQL
	 * 1.1 Update LOAD statement, or when URIs are dereferenced in FROM/FROM NAMED/USING/USING NAMED clauses.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#inputFormat">inputFormat</a>
	 */
	public static final IRI INPUT_FORMAT;

	/**
	 * Language
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Language}.
	 * <p>
	 * An instance of sd:Language represents one of the SPARQL languages, including specific configurations providing
	 * particular features or extensions. This document defines three instances of sd:Language: sd:SPARQL10Query,
	 * sd:SPARQL11Query, and sd:SPARQL11Update.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Language">Language</a>
	 */
	public static final IRI LANGUAGE;

	/**
	 * language extension
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#languageExtension}.
	 * <p>
	 * Relates an instance of sd:Service to a resource representing an implemented extension to the SPARQL Query or
	 * Update language.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#languageExtension">languageExtension</a>
	 */
	public static final IRI LANGUAGE_EXTENSION;

	/**
	 * name
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#name}.
	 * <p>
	 * Relates a named graph to the name by which it may be referenced in a FROM/FROM NAMED clause. The object of the
	 * sd:name property is an IRI.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#name">name</a>
	 */
	public static final IRI NAME;

	/**
	 * named graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#namedGraph}.
	 * <p>
	 * Relates an instance of sd:GraphCollection (or its subclass sd:Dataset) to the description of one of its named
	 * graphs. The description of such a named graph MUST include the sd:name property and MAY include the sd:graph
	 * property.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#namedGraph">namedGraph</a>
	 */
	public static final IRI NAMED_GRAPH_PROPERTY;

	/**
	 * Named Graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#NamedGraph}.
	 * <p>
	 * An instance of sd:NamedGraph represents a named graph having a name (via sd:name) and an optional graph
	 * description (via sd:graph).
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#NamedGraph">NamedGraph</a>
	 */
	public static final IRI NAMED_GRAPH_CLASS;

	/**
	 * property feature
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#propertyFeature}.
	 * <p>
	 * Relates an instance of sd:Service to a resource representing an implemented feature that extends the SPARQL Query
	 * or Update language and that is accessed by using the named property.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#propertyFeature">propertyFeature</a>
	 */
	public static final IRI PROPERTY_FEATURE;

	/**
	 * Requires Dataset
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#RequiresDataset}.
	 * <p>
	 * sd:RequiresDataset, when used as the object of the sd:feature property, indicates that the SPARQL service
	 * requires an explicit dataset declaration (based on either FROM/FROM NAMED clauses in a query, USING/USING NAMED
	 * clauses in an update, or the appropriate SPARQL Protocol parameters).
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#RequiresDataset">RequiresDataset</a>
	 */
	public static final IRI REQUIRES_DATASET;

	/**
	 * result format
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#resultFormat}.
	 * <p>
	 * Relates an instance of sd:Service to a format that is supported for serializing query results.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#resultFormat">resultFormat</a>
	 */
	public static final IRI RESULT_FORMAT;

	/**
	 * Service
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#Service}.
	 * <p>
	 * An instance of sd:Service represents a SPARQL service made available via the SPARQL Protocol.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#Service">Service</a>
	 */
	public static final IRI SERVICE;

	/**
	 * SPARQL 1.0 Query
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#SPARQL10Query}.
	 * <p>
	 * sd:SPARQL10Query is an sd:Language representing the SPARQL 1.0 Query language.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#SPARQL10Query">SPARQL10Query</a>
	 */
	public static final IRI SPARQL_10_QUERY;

	/**
	 * SPARQL 1.1 Query
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#SPARQL11Query}.
	 * <p>
	 * sd:SPARQL11Query is an sd:Language representing the SPARQL 1.1 Query language.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#SPARQL11Query">SPARQL11Query</a>
	 */
	public static final IRI SPARQL_11_QUERY;

	/**
	 * SPARQL 1.1 Update
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#SPARQL11Update}.
	 * <p>
	 * sd:SPARQLUpdate is an sd:Language representing the SPARQL 1.1 Update language.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#SPARQL11Update">SPARQL11Update</a>
	 */
	public static final IRI SPARQL_11_UPDATE;

	/**
	 * supported entailment profile
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#supportedEntailmentProfile}.
	 * <p>
	 * Relates a named graph description with a resource representing a supported profile of the entailment regime (as
	 * declared by sd:entailmentRegime) used for basic graph pattern matching over that graph.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#supportedEntailmentProfile">
	 *      supportedEntailmentProfile</a>
	 */
	public static final IRI SUPPORTED_ENTAILMENT_PROFILE;

	/**
	 * supported language
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#supportedLanguage}.
	 * <p>
	 * Relates an instance of sd:Service to a SPARQL language (e.g. Query and Update) that it implements.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#supportedLanguage">supportedLanguage</a>
	 */
	public static final IRI SUPPORTED_LANGUAGE;

	/**
	 * Union Default Graph
	 * <p>
	 * {@code http://www.w3.org/ns/sparql-service-description#UnionDefaultGraph}.
	 * <p>
	 * sd:UnionDefaultGraph, when used as the object of the sd:feature property, indicates that the default graph of the
	 * dataset used during query and update evaluation (when an explicit dataset is not specified) is comprised of the
	 * union of all the named graphs in that dataset.
	 *
	 * @see <a href="http://www.w3.org/ns/sparql-service-description#UnionDefaultGraph">UnionDefaultGraph</a>
	 */
	public static final IRI UNION_DEFAULT_GRAPH;

	static {

		AGGREGATE = Vocabularies.createIRI(SD.NAMESPACE, "Aggregate");
		AVAILBLE_GRAPHS = Vocabularies.createIRI(SD.NAMESPACE, "availableGraphs");
		BASIC_FEDERATED_QUERY = Vocabularies.createIRI(SD.NAMESPACE, "BasicFederatedQuery");
		DATASET = Vocabularies.createIRI(SD.NAMESPACE, "Dataset");
		DEFAULT_DATASET = Vocabularies.createIRI(SD.NAMESPACE, "defaultDataset");
		DEFAULT_ENTAILMENT_REGIME = Vocabularies.createIRI(SD.NAMESPACE, "defaultEntailmentRegime");
		DEFAULT_GRAPH = Vocabularies.createIRI(SD.NAMESPACE, "defaultGraph");
		DEFAULT_SUPPORTED_ENTAILMENT_PROFILE = Vocabularies.createIRI(SD.NAMESPACE,
				"defaultSupportedEntailmentProfile");
		DEREFERENCES_URIS = Vocabularies.createIRI(SD.NAMESPACE, "DereferencesURIs");
		EMPTY_GRAPHS = Vocabularies.createIRI(SD.NAMESPACE, "EmptyGraphs");
		ENDPOINT = Vocabularies.createIRI(SD.NAMESPACE, "endpoint");
		ENTAILMENT_PROFILE = Vocabularies.createIRI(SD.NAMESPACE, "EntailmentProfile");
		ENTAILMENT_REGIME_CLASS = Vocabularies.createIRI(SD.NAMESPACE, "EntailmentRegime");
		ENTAILMENT_REGIME_PROPERTY = Vocabularies.createIRI(SD.NAMESPACE, "entailmentRegime");
		EXTENSION_AGGREGATE = Vocabularies.createIRI(SD.NAMESPACE, "extensionAggregate");
		EXTENSION_FUNCTION = Vocabularies.createIRI(SD.NAMESPACE, "extensionFunction");
		FEATURE_CLASS = Vocabularies.createIRI(SD.NAMESPACE, "Feature");
		FEATURE_PROPERTY = Vocabularies.createIRI(SD.NAMESPACE, "feature");
		FUNCTION = Vocabularies.createIRI(SD.NAMESPACE, "Function");
		GRAPH_PROPERTY = Vocabularies.createIRI(SD.NAMESPACE, "graph");
		GRAPH_CLASS = Vocabularies.createIRI(SD.NAMESPACE, "Graph");
		GRAPH_COLLECTION = Vocabularies.createIRI(SD.NAMESPACE, "GraphCollection");
		INPUT_FORMAT = Vocabularies.createIRI(SD.NAMESPACE, "inputFormat");
		LANGUAGE = Vocabularies.createIRI(SD.NAMESPACE, "Language");
		LANGUAGE_EXTENSION = Vocabularies.createIRI(SD.NAMESPACE, "languageExtension");
		NAME = Vocabularies.createIRI(SD.NAMESPACE, "name");
		NAMED_GRAPH_PROPERTY = Vocabularies.createIRI(SD.NAMESPACE, "namedGraph");
		NAMED_GRAPH_CLASS = Vocabularies.createIRI(SD.NAMESPACE, "NamedGraph");
		PROPERTY_FEATURE = Vocabularies.createIRI(SD.NAMESPACE, "propertyFeature");
		REQUIRES_DATASET = Vocabularies.createIRI(SD.NAMESPACE, "RequiresDataset");
		RESULT_FORMAT = Vocabularies.createIRI(SD.NAMESPACE, "resultFormat");
		SERVICE = Vocabularies.createIRI(SD.NAMESPACE, "Service");
		SPARQL_10_QUERY = Vocabularies.createIRI(SD.NAMESPACE, "SPARQL10Query");
		SPARQL_11_QUERY = Vocabularies.createIRI(SD.NAMESPACE, "SPARQL11Query");
		SPARQL_11_UPDATE = Vocabularies.createIRI(SD.NAMESPACE, "SPARQL11Update");
		SUPPORTED_ENTAILMENT_PROFILE = Vocabularies.createIRI(SD.NAMESPACE, "supportedEntailmentProfile");
		SUPPORTED_LANGUAGE = Vocabularies.createIRI(SD.NAMESPACE, "supportedLanguage");
		UNION_DEFAULT_GRAPH = Vocabularies.createIRI(SD.NAMESPACE, "UnionDefaultGraph");
	}

	private SD() {
		// static access only
	}
}