foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/descriptors/RelationalDescriptor.java

/*
 * 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:
//     Oracle - initial API and implementation from Oracle TopLink
//
package org.eclipse.persistence.descriptors;

import java.util.*;

import org.eclipse.persistence.exceptions.*;

/**
 * <p><b>Purpose</b>: EclipseLink has been designed to take advantage of the similarities between
 * relational databases and objects while accommodating for their differences, providing an object
 * oriented wrapper for relational databases. This is accomplished through the use of Descriptors.
 * A descriptor is a pure specification class with all its behavior deputized to DescriptorEventManager,
 * DescriptorQueryManager and ObjectBuilder. Look at the following variables for the list
 * of specification on the descriptor.
 * <p>
 * A Descriptor is a set of mappings that describe how an objects's data is to be represented in a
 * relational database. It contains mappings from the class instance variables to the table's fields,
 * as well as the transformation routines necessary for storing and retrieving attributes. As such
 * the descriptor acts as the link between the Java object and its database representation.
 * <p>
 * Every descriptor is initialized with the following information:
 * <ul>
 * <li> The Java class its describes, and the corresponding table(s) for storing instances of the class.
 * <li> The primary key of the table.
 * <li> A list of query keys for field names.
 * <li> A description of the objects's attributes and relationships. This information is stored in mappings.
 * <li> A set of user selectable properties for tailoring the behavior of the descriptor.
 * </ul>
 *
 * <p> This descriptor subclass should be used for object-relational mapping,
 * and allows for other datatype mappings to be done in the XML, EIS and OR sibling classes.
 *
 * @see DescriptorEventManager
 * @see DescriptorQueryManager
 * @see InheritancePolicy
 * @see InterfacePolicy
 */
public class RelationalDescriptor extends ClassDescriptor {

    /**
     * PUBLIC:
     * Return a new descriptor.
     */
    public RelationalDescriptor() {
        super();
    }

    /**
     * PUBLIC:
     * Return if the descriptor maps to a relational table.
     */
    @Override
    public boolean isRelationalDescriptor() {
        return true;
    }

    /**
     * PUBLIC:
     * Specify the table name for the class of objects the receiver describes.
     * If the table has a qualifier it should be specified using the dot notation,
     * (i.e. "userid.employee"). This method is used if there is more than one table.
     */
    @Override
    public void addTableName(String tableName) {
        super.addTableName(tableName);
    }

    /**
     * PUBLIC:
     * Return the name of the descriptor's first table.
     * This method must only be called on single table descriptors.
     */
    @Override
    public String getTableName() {
        return super.getTableName();
    }

    /**
     * PUBLIC:
     * Return the table names.
     */
    @Override
    public Vector getTableNames() {
        return super.getTableNames();
    }

    /**
     * PUBLIC:
     * The descriptors default table can be configured if the first table is not desired.
     */
    @Override
    public void setDefaultTableName(String defaultTableName) {
        super.setDefaultTableName(defaultTableName);
    }

    /**
     * PUBLIC:
     * Specify the table name for the class of objects the receiver describes.
     * If the table has a qualifier it should be specified using the dot notation,
     * (i.e. "userid.employee"). This method is used for single table.
     */
    @Override
    public void setTableName(String tableName) throws DescriptorException {
        super.setTableName(tableName);
    }

    /**
     * PUBLIC:
     * Specify the all table names for the class of objects the receiver describes.
     * If the table has a qualifier it should be specified using the dot notation,
     * (i.e. "userid.employee"). This method is used for multiple tables
     */
    @Override
    public void setTableNames(Vector tableNames) {
        super.setTableNames(tableNames);
    }

    /**
     * PUBLIC: Set the table Qualifier for this descriptor.  This table creator will be used for
     * all tables in this descriptor
     */
    @Override
    public void setTableQualifier(String tableQualifier) {
        super.setTableQualifier(tableQualifier);
    }

}