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/*
* Copyright (c) 2011, 2018 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:
// James Sutherland - initial API and implementation
package org.eclipse.persistence.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.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* RoundRobinPartitioning sends requests in a round robin fashion to the set of connection pools.
* It is for load-balancing read queries across a cluster of database machines.
* It requires that the full database be replicated on each machine, so does not support partitioning.
* The data should either be read-only, or writes should be replicated on the database.
* <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.RoundRobinPartitioningPolicy
* @author James Sutherland
* @since EclipseLink 2.2
*/
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)
public @interface RoundRobinPartitioning {
/**
* The name of the partition policy, names must be unique for the persistence unit.
*/
String name();
/**
* List of connection pool names to load balance across.
* Defaults to all defined pools in the ServerSession.
*/
String[] connectionPools() default {};
/**
* This allows for a set of database to be written to and kept in synch,
* and have reads load-balanced across the databases.
*/
boolean replicateWrites() default false;
}
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