foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/helper/JPAConversionManager.java

/*
 * Copyright (c) 1998, 2021 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.internal.helper;

/**
 * <p>
 * <b>Purpose</b>: Extension to the existing conversion manager to support the
 * EJB 3.0 spec.
 * <p>
 * <b>Responsibilities</b>:
 * <ul>
 * <li> Allow a null value default to be read into primitives. With the current
 * conversion manager, setting a null into a primitive causes and exception.
 * This conversion manager was added to avoid that exception and therefore, add
 * support for schemas that were built before the object model was mapped
 * (using a primitive). Therefore, EclipseLink will not change the null column value
 * in the database through this conversion. The value on the database will only
 * be changed if the user actually sets a new primitive value.
 * <li> Allows users to define their own set of default null values to be used
 * in the conversion.
 * </ul>
 *
 * @author Guy Pelletier
 * @since TopLink 10.1.4 RI
 */
public class JPAConversionManager extends ConversionManager {
    public JPAConversionManager() {
        super();
    }

    /**
     * INTERNAL:
     */
    @Override
    public <T> T getDefaultNullValue(Class<T> theClass) {
        Object defaultNullValue = null;
        if (this.defaultNullValues != null){
            defaultNullValue = getDefaultNullValues().get(theClass);
        }
        if (defaultNullValue == null && theClass.isPrimitive()) {
            if(Double.TYPE.equals(theClass)){
                return (T) Double.valueOf(0D);
            }  else if(Long.TYPE.equals(theClass)) {
                return (T) Long.valueOf(0L);
            } else if(Character.TYPE.equals(theClass)){
                return (T) Character.valueOf('\u0000');
            } else if(Float.TYPE.equals(theClass)){
                return (T)  Float.valueOf(0F);
            } else if(Short.TYPE.equals(theClass)){
                return (T) Short.valueOf((short) 0);
            } else if(Byte.TYPE.equals(theClass)){
                return (T)  Byte.valueOf((byte) 0);
            } else if(Boolean.TYPE.equals(theClass)){
                return (T) Boolean.FALSE;
            } else {
                return (T) Integer.valueOf(0);
            }
        } else {
            return (T) defaultNullValue;
        }
    }
}