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/*
 * Copyright (c) 2008, 2023 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:
//     Linda DeMichiel - 2.1
//     Linda DeMichiel - 2.0

package jakarta.persistence;

import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Specifies the value of the discriminator column for the annotated
 * entity type.
 *
 * 

The {@code DiscriminatorValue} annotation can only be specified * on a concrete entity class. * *

If the {@code DiscriminatorValue} annotation is not specified, * and a discriminator column is used, a provider-specific function * is used to generate a value representing the entity type. If the * {@link DiscriminatorType} is {@link DiscriminatorType#STRING * STRING}, the discriminator value default is the entity name. * *

The inheritance strategy and the discriminator column are only * specified for the root of an entity class hierarchy or subhierarchy * in which a different inheritance strategy is applied. But the * discriminator value, if not defaulted, should be specified for each * concrete entity class in the hierarchy. * *

Example: * {@snippet : * @Entity * @Table(name = "CUST") * @Inheritance(strategy = SINGLE_TABLE) * @DiscriminatorColumn(name = "DISC", discriminatorType = STRING, length = 20) * @DiscriminatorValue("CUSTOMER") * public class Customer { ... } * * @Entity * @DiscriminatorValue("VCUSTOMER") * public class ValuedCustomer extends Customer { ... } * } * * @see DiscriminatorColumn * * @since 1.0 */ @Target({TYPE}) @Retention(RUNTIME) public @interface DiscriminatorValue { /** * (Optional) The value that indicates that the row is an entity of * the annotated entity type. * *

If the {@code DiscriminatorValue} annotation is not specified * and a discriminator column is used, a provider-specific function * is used to generate a value representing the entity type. If the * {@link DiscriminatorType} is {@link DiscriminatorType#STRING * STRING}, the discriminator value default is the entity name. */ String value(); }





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