code: package it.unibz.inf.ontop.spec.ontology;
  
  /*
   * #%L
   * ontop-obdalib-core
   * %%
   * Copyright (C) 2009 - 2014 Free University of Bozen-Bolzano
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  
  import org.apache.commons.rdf.api.IRI;
  
  /**
   * Represents ObjectPropertyExpression from the OWL 2 QL Specification
   * 
   * ObjectPropertyExpression := ObjectProperty | InverseObjectProperty
   * InverseObjectProperty := 'ObjectInverseOf' '(' ObjectProperty ')'
   * 
   * Support for owl:topObjectProperty and owl:bottomObjectProperty
   *     - the inverses of the two coincide with themselves 
   * 
   * @author Roman Kontchakov
   *
   */
  
  public interface ObjectPropertyExpression extends DescriptionBT {
  
  	/**
  	 * checks whether the property expression is the inverse of an object property
  	 *
  	 * @return true if the property is the inverse (false otherwise)
  	 */
  	
  	boolean isInverse();
  
  	/**
  	 * the IRI of the object property
  	 *
  	 */
  	
  	IRI getIRI();
  
  	/**
  	 * the inverse of the object property
  	 * <p>
  	 *    (the inverse of an inverted property is the property itself)
  	 * <p>   
  	 *    (the inverses of owl:topObjectProperty and owl:bottomObjectProperty
  	 *      are the properties themselves)
  	 * 
  	 * @return
  	 */
  	
  	ObjectPropertyExpression getInverse();
  
  	/**
  	 * the domain class expression for the object property 
  	 * <p>
  	 * (in DL, the unqualified existential quantifier \exists R for property R)
  	 * 
  	 * @return class expression for the domain
  	 */
  	
  	ObjectSomeValuesFrom getDomain();
  	
  	/**
  	 * the range class expression for the object property
  	 * <p> 
  	 * (the range of a property coincides with the domain of its inverse)
  	 * <p>
  	 * (in DL, the unqualified existential quantifier \exists R^- for property R)
  	 * 
  	 * @return class expression for the range
  	 */
  	
  	ObjectSomeValuesFrom getRange();
  }
  