code: package it.unibz.inf.ontop.dbschema;
  
  /*
   * #%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 com.google.common.collect.ImmutableList;
  import it.unibz.inf.ontop.dbschema.impl.UniqueConstraintImpl;
  
  /**
   * Primary key or a unique constraint
   *
   * PRIMARY KEY (columnName (, columnName)*)
   * UNIQUE (columnName (, columnName)*)
   *
   * (a form of equality-generating dependencies)
   *
   * @author Roman Kontchakov
   *
   */
  
  public interface UniqueConstraint extends FunctionalDependency {
  
  	/**
  	 * return the name of the constraint
  	 *
  	 * @return name
  	 */
  
  	String getName();
  
  	/**
  	 * return true if it is a primary key and false otherwise
  	 *
  	 * @return true if it is a primary key constraint (false otherwise)
  	 */
  
  	boolean isPrimaryKey();
  
  	/**
  	 * return the list of attributes in the unique constraint
  	 *
  	 * @return list of attributes
  	 */
  
  	ImmutableList<Attribute> getAttributes();
  
  
  	/**
  	 * creates a UNIQUE constraint builder
  	 *
  	 * @param relation
  	 * @param name
  	 * @return
  	 */
  
  	static Builder builder(NamedRelationDefinition relation, String name) {
  		return UniqueConstraintImpl.builder(relation, name);
  	}
  
  	/**
  	 * creates a PRIMARY KEY  builder
  	 *
  	 * @param relation
  	 * @param name
  	 * @return
  	 */
  
  	static Builder primaryKeyBuilder(NamedRelationDefinition relation, String name) {
  		return UniqueConstraintImpl.primaryKeyBuilder(relation, name);
  	}
  
  
  	static void primaryKeyOf(Attribute attribute) {
  		NamedRelationDefinition relation = (NamedRelationDefinition)attribute.getRelation();
  		primaryKeyBuilder(relation, "PK")
  				.addDeterminant(attribute.getIndex()).build();
  	}
  
  	static void primaryKeyOf(Attribute attribute1, Attribute attribute2) {
  		if (attribute1.getRelation() != attribute2.getRelation())
  			throw new IllegalArgumentException();
  
  		NamedRelationDefinition relation = (NamedRelationDefinition)attribute1.getRelation();
  
  		primaryKeyBuilder(relation, "PK")
  				.addDeterminant(attribute1.getIndex())
  				.addDeterminant(attribute2.getIndex()).build();
  	}
  }
  