org.hibernate.annotations.Formula Maven / Gradle / Ivy
/*
* 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.annotations;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Defines a formula (derived value) which is a SQL fragment that acts as a @Column alternative in most cases.
* Represents read-only state.
*
* In certain cases @ColumnTransformer might be a better option, especially as it leaves open the option of still
* being writable.
*
*
* // perform calculations
* @Formula( "sub_total + (sub_total * tax)" )
* long getTotalCost() { ... }
*
*
*
* // call functions
* @Formula( "upper( substring( middle_name, 1 ) )" )
* Character getMiddleInitial() { ... }
*
*
*
* // this might be better handled through @ColumnTransformer
* @Formula( "decrypt(credit_card_num)" )
* String getCreditCardNumber() { ... }
*
*
* @see ColumnTransformer
*
* @author Emmanuel Bernard
* @author Steve Ebersole
*/
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface Formula {
/**
* The formula string.
*/
String value();
}