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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 implementation
package org.eclipse.persistence.annotations;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* A BatchFetch annotation can be used on any relationship mapping,
* (OneToOne, ManyToOne, OneToMany, ManyToMany, ElementCollection, BasicCollection, BasicMap).
* It allows the related objects to be batch read in a single query.
* Batch fetching can also be set at the query level, and it is
* normally recommended to do so as all queries may not require batching.
*
* @author James Sutherland
* @since EclipseLink 2.1
*/
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface BatchFetch {
/**
* (Optional) The type of batch-fetch to use.
* Either JOIN, EXISTS or IN.
* JOIN is the default.
*/
BatchFetchType value() default BatchFetchType.JOIN;
/**
* Define the default batch fetch size.
* This is only used for IN type batch reading and defines
* the number of keys used in each IN clause.
* The default size is 256, or the query's pageSize for cursor queries.
*/
int size() default -1;
}
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