org.jooq.Converter Maven / Gradle / Ivy
/**
* Copyright (c) 2009-2015, Data Geekery GmbH (http://www.datageekery.com)
* All rights reserved.
*
* 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.
*
* Other licenses:
* -----------------------------------------------------------------------------
* Commercial licenses for this work are available. These replace the above
* ASL 2.0 and offer limited warranties, support, maintenance, and commercial
* database integrations.
*
* For more information, please visit: http://www.jooq.org/licenses
*
*
*
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*/
package org.jooq;
import java.io.Serializable;
import org.jooq.impl.SQLDataType;
/**
* A Converter for data types.
*
* A general data type conversion interface that can be provided to jOOQ at
* various places in order to perform custom data type conversion. Conversion is
* directed, this means that the Converter is used
*
* - to load database types converting them to user types "FROM" the database.
* Hence, {@link #fromType()} is the type as defined in the database.
* - to store user types converting them to database types "TO" the database.
* Hence, {@link #toType()} is the user-defined type
*
*
* Note: In order to avoid unwanted side-effects, it is highly recommended (yet
* not required) for {@link #from(Object)} and {@link #to(Object)} to be
* reciprocal. The two methods are reciprocal, if for all
* X and Y, it can be said that
*
* - if
Y.equals(converter.from(X)), then
* X.equals(converter.to(Y)).
* -
*
X.equals(converter.from(converter.to(X)))
* X.equals(converter.to(converter.from(X)))
*
* Furthermore, it is recommended (yet not required) that
*
* converter.from(null) == nullconverter.to(null) == null
*
* @author Lukas Eder
* @param The database type - i.e. any type available from
* {@link SQLDataType}
* @param The user type
*/
public interface Converter extends Serializable {
/**
* Convert a database object to a user object
*
* @param databaseObject The database object
* @return The user object
*/
U from(T databaseObject);
/**
* Convert a user object to a database object
*
* @param userObject The user object
* @return The database object
*/
T to(U userObject);
/**
* The database type
*/
Class fromType();
/**
* The user type
*/
Class toType();
}