javax.persistence.ConstructorResult Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2008 - 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
* Linda DeMichiel - Java Persistence 2.0
*
******************************************************************************/
package javax.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} 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
* columns element of the 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:
*
* 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 ColumnResult
*
* @since Java Persistence 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();
}