/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.engine.jdbc.internal;

import java.sql.DatabaseMetaData;

/**
 * Describes the instrinsic nullability of a data type as reported by the JDBC driver.
 *
 * @author Steve Ebersole
 */
public enum TypeNullability {
	/**
	 * The data type can accept nulls
	 * @see DatabaseMetaData#typeNullable
	 */
	NULLABLE,
	/**
	 * The data type cannot accept nulls
	 * @see DatabaseMetaData#typeNoNulls
	 */
	NON_NULLABLE,
	/**
	 * It is unknown if the data type accepts nulls
	 * @see DatabaseMetaData#typeNullableUnknown
	 */
	UNKNOWN;

	/**
	 * Based on the code retrieved from {@link DatabaseMetaData#getTypeInfo()} for the {@code NULLABLE}
	 * column, return the appropriate enum.
	 *
	 * @param code The retrieved code value.
	 *
	 * @return The corresponding enum.
	 */
	public static TypeNullability interpret(short code) {
		switch ( code ) {
			case DatabaseMetaData.typeNullable: {
				return NULLABLE;
			}
			case DatabaseMetaData.typeNoNulls: {
				return NON_NULLABLE;
			}
			case DatabaseMetaData.typeNullableUnknown: {
				return UNKNOWN;
			}
			default: {
				throw new IllegalArgumentException( "Unknown type nullability code [" + code + "] enountered" );
			}
		}
	}
}