/******************************************************************************* | |
* Copyright (c) 2011, 2013 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 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: | |
* James Sutherland - initial API and implementation | |
******************************************************************************/ | |
package org.eclipse.persistence.annotations; | |
import java.lang.annotation.Retention; | |
import java.lang.annotation.Target; | |
import javax.persistence.Column; | |
import static java.lang.annotation.ElementType.FIELD; | |
import static java.lang.annotation.ElementType.METHOD; | |
import static java.lang.annotation.ElementType.TYPE; | |
import static java.lang.annotation.RetentionPolicy.RUNTIME; | |
/** | |
* HashPartitioning partitions access to a database cluster by the hash of a field value from the object, | |
* such as the object's location, or tenant. | |
* The hash indexes into the list of connection pools. | |
* All write or read request for object's with that hash value are sent to the server. | |
* If a query does not include the field as a parameter, then it can either be sent | |
* to all server's and unioned, or left to the sesion's default behavior. | |
* <p> | |
* Partitioning can be enabled on an Entity, relationship, query, or session/persistence unit. | |
* Partition policies are globally named to allow reuse, | |
* the partitioning policy must also be set using the @Partitioned annotation to be used. | |
* | |
* @see Partitioned | |
* @see org.eclipse.persistence.descriptors.partitioning.HashPartitioningPolicy | |
* @author James Sutherland | |
* @since EclipseLink 2.2 | |
*/ | |
@Target({TYPE, METHOD, FIELD}) | |
@Retention(RUNTIME) | |
public @interface HashPartitioning { | |
/** | |
* The name of the partition policy, names must be unique for the persistence unit. | |
*/ | |
String name(); | |
/** | |
* The database column or query parameter to partition queries by. | |
* This is the table column name, not the class attribute name. | |
* The column value must be included in the query and should normally be part of the object's Id. | |
* This can also be the name of a query parameter. | |
* If a query does not contain the field the query will not be partitioned. | |
*/ | |
Column partitionColumn(); | |
/** | |
* List of connection pool names to partition across. | |
* Defaults to all defined pools in the ServerSession. | |
*/ | |
String[] connectionPools() default {}; | |
/** | |
* Defines if queries that do not contain the partition field should be sent | |
* to every database and have the result unioned. | |
*/ | |
boolean unionUnpartitionableQueries() default false; | |
} |