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
/*******************************************************************************
 * 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 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 Also:
SqlResultSetMapping
ColumnResult
Since:
Java Persistence 2.1/**
 * Used in conjunction with the {@link SqlResultSetMapping} annotation to map the SELECT
 * clause of a SQL query to a constructor.
 *
 * <p>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
 * <code>columns</code> element of the <code>ConstructorResult</code>
 * 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.
 * 
 * <pre>
 *
 * 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");
 *
 *   &#064;SqlResultSetMapping(
 *       name="CustomerDetailsResult",
 *       classes={
 *          &#064;ConstructorResult(
 *               targetClass=com.acme.CustomerDetails.class,
 *                 columns={
 *                    &#064;ColumnResult(name="id"),
 *                    &#064;ColumnResult(name="name"),
 *                    &#064;ColumnResult(name="orderCount"),
 *                    &#064;ColumnResult(name="avgOrder", type=Double.class)
 *                    }
 *          )
 *       }
 *      )
 *
 * </pre>
 *
 * @see SqlResultSetMapping
 * @see ColumnResult
 *
 * @since Java Persistence 2.1
 */
@Target({}) 
@Retention(RUNTIME)

public @interface ConstructorResult { 

    
(Required) The class whose constructor is to be invoked. /** (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.
/** 
     *  (Required) The mapping of columns in the SELECT list to the arguments
     *  of the intended constructor, in order.
     */
    ColumnResult[] columns();
}