001/*
002 *    GeoAPI - Java interfaces for OGC/ISO standards
003 *    Copyright © 2014-2023 Open Geospatial Consortium, Inc.
004 *    http://www.geoapi.org
005 *
006 *    Licensed under the Apache License, Version 2.0 (the "License");
007 *    you may not use this file except in compliance with the License.
008 *    You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *    Unless required by applicable law or agreed to in writing, software
013 *    distributed under the License is distributed on an "AS IS" BASIS,
014 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 *    See the License for the specific language governing permissions and
016 *    limitations under the License.
017 */
018package org.opengis.metadata.identification;
019
020import java.net.URI;
021import org.opengis.annotation.UML;
022import org.opengis.metadata.citation.Citation;
023import org.opengis.util.InternationalString;
024
025import static org.opengis.annotation.Obligation.*;
026import static org.opengis.annotation.Specification.ISO_19115;
027
028
029/**
030 * Specification of a class to categorize keywords in a domain-specific
031 * vocabulary that has a binding to a formal ontology.
032 *
033 * @author  Rémi Maréchal (Geomatys)
034 * @version 3.1
035 * @since   3.1
036 *
037 * @see Keywords#getKeywordClass()
038 */
039@UML(identifier="MD_KeywordClass", specification=ISO_19115)
040public interface KeywordClass {
041    /**
042     * A character string to label the keyword category in natural language.
043     *
044     * @return the keyword category in natural language.
045     */
046    @UML(identifier="className", obligation=MANDATORY, specification=ISO_19115)
047    InternationalString getClassName();
048
049    /**
050     * URI of concept in the ontology specified by the {@linkplain #getOntology() ontology} citation
051     * and labeled by the {@linkplain #getClassName() class name}.
052     *
053     * @return URI of concept in the ontology, or {@code null} if none.
054     */
055    @UML(identifier="conceptIdentifier", obligation=OPTIONAL, specification=ISO_19115)
056    default URI getConceptIdentifier() {
057        return null;
058    }
059
060    /**
061     * A reference that binds the keyword class to a formal conceptualization
062     * of a knowledge domain for use in semantic processing.
063     *
064     * <div class="note"><b>Note:</b>
065     * {@linkplain Keywords#getKeywords() keywords} in the associated {@link Keywords} list
066     * must be within the scope of this ontology.
067     * </div>
068     *
069     * @return a reference that binds the keyword class to a formal conceptualization.
070     */
071    @UML(identifier="ontology", obligation=MANDATORY, specification=ISO_19115)
072    Citation getOntology();
073}