Java tutorial
/******************************************************************************* * Copyright (c) 2011 - 2013 Oracle Corporation. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * Contributors: * Linda DeMichiel - Java Persistence 2.1 * ******************************************************************************/ package javax.persistence; /** * A class that implements this interface can be used to convert * entity attribute state into database column representation * and back again. * Note that the X and Y types may be the same Java type. * * @param <X> the type of the entity attribute * @param <Y> the type of the database column */ public interface AttributeConverter<X, Y> { /** * Converts the value stored in the entity attribute into the * data representation to be stored in the database. * * @param attribute the entity attribute value to be converted * @return the converted data to be stored in the database * column */ public Y convertToDatabaseColumn(X attribute); /** * Converts the data stored in the database column into the * value to be stored in the entity attribute. * Note that it is the responsibility of the converter writer to * specify the correct <code>dbData</code> type for the corresponding * column for use by the JDBC driver: i.e., persistence providers are * not expected to do such type conversion. * * @param dbData the data from the database column to be * converted * @return the converted value to be stored in the entity * attribute */ public X convertToEntityAttribute(Y dbData); }