AssociatedEntityKeyMetadata.java

/*
 * Hibernate OGM, Domain model persistence for NoSQL datastores
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.ogm.model.key.spi;

import org.hibernate.ogm.model.spi.Tuple;

/**
 * Provides meta-data about a one-to-one/many-to-one association represented by one or more columns contained within a
 * {@link Tuple}.
 *
 * @author Davide D'Alto
 * @author Gunnar Morling
 */
public interface AssociatedEntityKeyMetadata {

	/**
	 * Get the meta-data for the entity key on the other side of the represented association.
	 *
	 * @return The entity key meta-data
	 */
	EntityKeyMetadata getEntityKeyMetadata();

	/**
	 * Returns the name of the column in the target entity key corresponding to the given association key column.
	 * <p>
	 * E.g. let there be an entity key comprising the columns {@code id.countryCode} and {@code id.sequenceNo} which is
	 * referenced by the columns {@code address_id.countryCode} and {@code address_id.sequenceNo}. When invoked for the
	 * column {@code address_id.countryCode}, this method will return {@code id.countryCode}.
	 *
	 * @param associationKeyColumn The name of the column in the association
	 * @return The name of the corresponding column in the referenced entity key
	 */
	String getCorrespondingEntityKeyColumn(String associationKeyColumn);

	/**
	 * get the names of those columns of a tuple or association row which make up the represented association, i.e.
	 * the columns referring to the entity key on the other side.
	 *
	 * @return The association key columns names
	 */
	String[] getAssociationKeyColumns();
}