jpa/org.eclipse.persistence.jpa/src/main/java/org/eclipse/persistence/internal/jpa/metadata/columns/DiscriminatorClassMetadata.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:
//     03/26/2008-1.0M6 Guy Pelletier
//       - 211302: Add variable 1-1 mapping support to the EclipseLink-ORM.XML Schema
//     05/16/2008-1.0M8 Guy Pelletier
//       - 218084: Implement metadata merging functionality between mapping files
//     04/27/2010-2.1 Guy Pelletier
//       - 309856: MappedSuperclasses from XML are not being initialized properly
//     01/25/2011-2.3 Guy Pelletier
//       - 333913: @OrderBy and <order-by/> without arguments should order by primary
//     03/24/2011-2.3 Guy Pelletier
//       - 337323: Multi-tenant with shared schema support (part 1)
package org.eclipse.persistence.internal.jpa.metadata.columns;

import org.eclipse.persistence.exceptions.ValidationException;
import org.eclipse.persistence.internal.jpa.metadata.ORMetadata;

import org.eclipse.persistence.internal.jpa.metadata.accessors.MetadataAccessor;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataAccessibleObject;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataAnnotation;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataClass;

import org.eclipse.persistence.internal.jpa.metadata.xml.XMLEntityMappings;

import org.eclipse.persistence.mappings.VariableOneToOneMapping;

/**
 * INTERNAL:
 * A discriminator class is used within a variable one to one mapping.
 *
 * Key notes:
 * - any metadata mapped from XML to this class must be compared in the
 *   equals method.
 * - when loading from annotations, the constructor accepts the metadata
 *   accessor this metadata was loaded from. Used it to look up any
 *   'companion' annotation needed for processing.
 * - methods should be preserved in alphabetical order.
 *
 * @author Guy Pelletier
 * @since EclipseLink 1.0
 */
public class DiscriminatorClassMetadata extends ORMetadata {
    private MetadataClass m_valueClass;
    private String m_value;
    private String m_discriminator;

    /**
     * INTERNAL:
     * Used for XML loading.
     */
    public DiscriminatorClassMetadata() {
        super("<discriminator-class>");
    }

    /**
     * INTERNAL:
     * Used for annotation loading.
     */
    public DiscriminatorClassMetadata(MetadataAnnotation discriminatorClass, MetadataAccessor accessor) {
        super(discriminatorClass, accessor);

        setDiscriminator(discriminatorClass.getAttributeString("discriminator"));
        setValueClass(getMetadataClass(discriminatorClass.getAttributeString("value")));
    }

    /**
     * INTERNAL:
     */
    @Override
    public boolean equals(Object objectToCompare) {
        if (objectToCompare instanceof DiscriminatorClassMetadata) {
            DiscriminatorClassMetadata discriminatorClass = (DiscriminatorClassMetadata) objectToCompare;

            if (! valuesMatch(m_value, discriminatorClass.getValue())) {
                return false;
            }

            return valuesMatch(m_discriminator, discriminatorClass.getDiscriminator());
        }

        return false;
    }

    @Override
    public int hashCode() {
        int result = m_value != null ? m_value.hashCode() : 0;
        result = 31 * result + (m_discriminator != null ? m_discriminator.hashCode() : 0);
        return result;
    }

    /**
     * INTERNAL:
     * Used for OX mapping.
     */
    public String getDiscriminator() {
        return m_discriminator;
    }

    /**
     * INTERNAL:
     */
    public MetadataClass getValueClass() {
        return m_valueClass;
    }

    /**
     * INTERNAL:
     * Used for OX mapping.
     */
    public String getValue() {
        return m_value;
    }

    /**
     * INTERNAL:
     */
    @Override
    public void initXMLObject(MetadataAccessibleObject accessibleObject, XMLEntityMappings entityMappings) {
        super.initXMLObject(accessibleObject, entityMappings);

        m_valueClass = initXMLClassName(m_value);
    }

    /**
     * INTERNAL:
     * Process a discriminator class for the given variable one to one mapping.
     */
    public void process(VariableOneToOneMapping mapping) {
        if (mapping.getTypeIndicatorNameTranslation().containsValue(m_discriminator)) {
            throw ValidationException.multipleClassesForTheSameDiscriminator(m_discriminator, mapping.getAttributeName());
        }

        mapping.addClassNameIndicator(m_valueClass.getName(), m_discriminator);
    }

    /**
     * INTERNAL:
     * Used for OX mapping.
     */
    public void setDiscriminator(String discriminator) {
        m_discriminator= discriminator;
    }

    /**
     * INTERNAL:
     */
    public void setValueClass(MetadataClass value) {
        m_valueClass = value;
    }

    /**
     * INTERNAL:
     * Used for OX mapping.
     */
    public void setValue(String valueName) {
        m_value = valueName;
    }
}