code: package it.unibz.inf.ontop.model.term.impl;
  
  /*
   * #%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 it.unibz.inf.ontop.iq.node.VariableNullability;
  import it.unibz.inf.ontop.model.term.*;
  import it.unibz.inf.ontop.model.type.ObjectRDFType;
  import it.unibz.inf.ontop.model.type.TypeFactory;
  import org.apache.commons.rdf.api.IRI;
  
  import java.util.stream.Stream;
  
  
  /**
   * Provides a storage to put the URI constant.
   */
  public class IRIConstantImpl extends AbstractNonNullConstant implements IRIConstant {
  
  	private final IRI iri;
  	private final ObjectRDFType type;
  
  	protected IRIConstantImpl(IRI iri, TypeFactory typeFactory) {
  		this.iri = iri;
  		this.type = typeFactory.getIRITermType();
  	}
  	
  	@Override
  	public boolean equals(Object other) {
  		return (other instanceof IRIConstantImpl &&
  					this.iri.equals(((IRIConstantImpl) other).iri));
  	}
  
  	@Override
  	public int hashCode() {
  		return iri.hashCode();
  	}
  
  	@Override
  	public IRI getIRI() {
  		return iri;
  	}
  
  	@Override
  	public boolean isGround() {
  		return true;
  	}
  
  	@Override
  	public Stream<Variable> getVariableStream() {
  		return Stream.of();
  	}
  
  	@Override
  	public String toString() {
  		return "<" + iri.getIRIString() + ">";
  	}
  
  	@Override
  	public ObjectRDFType getType() {
  		return type;
  	}
  
  	@Override
  	public IncrementalEvaluation evaluateStrictEq(ImmutableTerm otherTerm, VariableNullability variableNullability) {
  		if (otherTerm instanceof Constant) {
  			if (((Constant) otherTerm).isNull())
  				return IncrementalEvaluation.declareIsNull();
  			return equals(otherTerm)
  					? IncrementalEvaluation.declareIsTrue()
  					: IncrementalEvaluation.declareIsFalse();
  		}
  		else
  			return otherTerm.evaluateStrictEq(this, variableNullability);
  	}
  
  	@Deprecated
  	public String getValue() {
  		return iri.getIRIString();
  	}
  }
  