| /* |
| * Copyright (c) 1998, 2020 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: |
| // 12/12/2008-1.1 Guy Pelletier |
| // - 249860: Implement table per class inheritance support. |
| package org.eclipse.persistence.descriptors; |
| |
| import org.eclipse.persistence.exceptions.DescriptorException; |
| import org.eclipse.persistence.queries.ReadAllQuery; |
| import org.eclipse.persistence.queries.ReadObjectQuery; |
| |
| /** |
| * <p><b>Purpose</b>: Provides the functionality to support a TABLE_PER_CLASS |
| * inheritance strategy. Resolves relational mappings and querying. |
| */ |
| public class TablePerClassPolicy extends InterfacePolicy { |
| |
| /** |
| * INTERNAL: |
| * Create a new policy. |
| * Only descriptors involved in inheritance should have a policy. |
| */ |
| public TablePerClassPolicy(ClassDescriptor descriptor) { |
| setDescriptor(descriptor); |
| } |
| |
| /** |
| * INTERNAL: |
| */ |
| @Override |
| public boolean isTablePerClassPolicy() { |
| return true; |
| } |
| |
| /** |
| * INTERNAL: |
| * Select all objects for a concrete descriptor. |
| */ |
| @Override |
| protected Object selectAllObjects(ReadAllQuery query) { |
| if (this.descriptor.isAbstract()) { |
| return query.getContainerPolicy().containerInstance(); |
| } |
| return super.selectAllObjects(query); |
| } |
| |
| /** |
| * INTERNAL: |
| * Select one object of any concrete subclass. |
| */ |
| @Override |
| protected Object selectOneObject(ReadObjectQuery query) throws DescriptorException { |
| if (this.descriptor.isAbstract()) { |
| return null; |
| } |
| return super.selectOneObject(query); |
| } |
| } |