org.eclipse.persistence.annotations.ValuePartitioning Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation
EclipseLink build based upon Git transaction f2b9fc5
There is a newer version: 5.0.0-B03
/*
 * Copyright (c) 2011, 2024 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 jakarta.persistence.Column;

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;

/**
 * ValuePartitioning partitions access to a database cluster by a field value from the object,
 * such as the object's location, or tenant.
 * Each value is assigned a specific server.
 * 
 * All write or read request for object's with that 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 session's default behavior.
 * 

 * 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 {@linkplain Partitioned} annotation to be used.
 *
 * @see Partitioned
 * @see org.eclipse.persistence.descriptors.partitioning.ValuePartitioningPolicy
 * @author James Sutherland
 * @since EclipseLink 2.2
 */
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)
public @interface ValuePartitioning {
    /**
     * 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();

    /** Store the value partitions. Each partition maps a value to a connectionPool. */
    ValuePartition[] partitions();

    /** The type of the start and end values. */
    Class partitionValueType() default String.class;

    /** The default connection pool is used for any unmapped values. */
    String defaultConnectionPool() 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;
}