jakarta.persistence.ConstructorResult Maven / Gradle / Ivy
/*
* Copyright (c) 2008, 2023 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
// Contributors:
// Linda DeMichiel - 2.1
// Linda DeMichiel - 2.0
package jakarta.persistence;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Used in conjunction with the {@link SqlResultSetMapping} or
* {@link NamedNativeQuery} annotation to map the SELECT clause
* of a SQL query to a constructor.
*
* Applies a constructor for the target class, passing in as
* arguments values from the specified columns. All columns
* corresponding to arguments of the intended constructor must
* be specified using the {@link #columns} element of the
* {@code ConstructorResult} annotation in the same order as that
* of the argument list of the constructor. Any entities returned
* as constructor results will be in either the new or detached
* state, depending on whether a primary key is retrieved for
* the constructed object.
*
*
Example:
* {@snippet :
* Query q = em.createNativeQuery(
* "SELECT c.id, c.name, " +
* "COUNT(o) as orderCount, " +
* "AVG(o.price) AS avgOrder " +
* "FROM Customer c, Orders o " +
* "WHERE o.cid = c.id " +
* "GROUP BY c.id, c.name",
* "CustomerDetailsResult");
*
* @SqlResultSetMapping(
* name = "CustomerDetailsResult",
* classes = {
* @ConstructorResult(
* targetClass = com.acme.CustomerDetails.class,
* columns = {
* @ColumnResult(name = "id"),
* @ColumnResult(name = "name"),
* @ColumnResult(name = "orderCount"),
* @ColumnResult(name = "avgOrder", type = Double.class)
* })
* })
* }
*
* @see SqlResultSetMapping
* @see NamedNativeQuery
* @see ColumnResult
*
* @since 2.1
*/
@Target({})
@Retention(RUNTIME)
public @interface ConstructorResult {
/**
* (Required) The class whose constructor is to be invoked.
*/
Class targetClass();
/**
* (Required) The mapping of columns in the SELECT list
* to the arguments of the intended constructor, in order.
*/
ColumnResult[] columns();
}