/*
 * Copyright 2008-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.jpa.domain.support;

import javax.persistence.PrePersist;
import javax.persistence.PreUpdate;

import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.data.auditing.AuditingHandler;
import org.springframework.data.domain.Auditable;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

JPA entity listener to capture auditing information on persiting and updating entities. To get this one flying be sure you configure it as entity listener in your orm.xml as follows: 
<persistence-unit-metadata>
    <persistence-unit-defaults>
        <entity-listeners>
            <entity-listener class="org.springframework.data.jpa.domain.support.AuditingEntityListener" />
        </entity-listeners>
    </persistence-unit-defaults>
</persistence-unit-metadata>

After that it's just a matter of activating auditing in your Spring config:
@Configuration
@EnableJpaAuditing
class ApplicationConfig {
}

<jpa:auditing auditor-aware-ref="yourAuditorAwarebean" />

Author:
Oliver Gierke, Thomas Darimont, Christoph Strobl, Mark Paluch/**
 * JPA entity listener to capture auditing information on persiting and updating entities. To get this one flying be
 * sure you configure it as entity listener in your {@code orm.xml} as follows:
 *
 * <pre>
 * &lt;persistence-unit-metadata&gt;
 *     &lt;persistence-unit-defaults&gt;
 *         &lt;entity-listeners&gt;
 *             &lt;entity-listener class="org.springframework.data.jpa.domain.support.AuditingEntityListener" /&gt;
 *         &lt;/entity-listeners&gt;
 *     &lt;/persistence-unit-defaults&gt;
 * &lt;/persistence-unit-metadata&gt;
 * </pre>
 *
 * After that it's just a matter of activating auditing in your Spring config:
 *
 * <pre>
 * &#064;Configuration
 * &#064;EnableJpaAuditing
 * class ApplicationConfig {
 *
 * }
 * </pre>
 *
 * <pre>
 * &lt;jpa:auditing auditor-aware-ref="yourAuditorAwarebean" /&gt;
 * </pre>
 *
 * @author Oliver Gierke
 * @author Thomas Darimont
 * @author Christoph Strobl
 * @author Mark Paluch
 */
@Configurable
public class AuditingEntityListener {

	private @Nullable ObjectFactory<AuditingHandler> handler;

	
Configures the AuditingHandler to be used to set the current auditor on the domain types touched. 
Params:
auditingHandler – must not be null./**
	 * Configures the {@link AuditingHandler} to be used to set the current auditor on the domain types touched.
	 *
	 * @param auditingHandler must not be {@literal null}.
	 */
	public void setAuditingHandler(ObjectFactory<AuditingHandler> auditingHandler) {

		Assert.notNull(auditingHandler, "AuditingHandler must not be null!");
		this.handler = auditingHandler;
	}

	
Sets modification and creation date and auditor on the target object in case it implements Auditable on persist events. 
Params:
target – /**
	 * Sets modification and creation date and auditor on the target object in case it implements {@link Auditable} on
	 * persist events.
	 *
	 * @param target
	 */
	@PrePersist
	public void touchForCreate(Object target) {

		Assert.notNull(target, "Entity must not be null!");

		if (handler != null) {

			AuditingHandler object = handler.getObject();
			if (object != null) {
				object.markCreated(target);
			}
		}
	}

	
Sets modification and creation date and auditor on the target object in case it implements Auditable on update events. 
Params:
target – /**
	 * Sets modification and creation date and auditor on the target object in case it implements {@link Auditable} on
	 * update events.
	 *
	 * @param target
	 */
	@PreUpdate
	public void touchForUpdate(Object target) {

		Assert.notNull(target, "Entity must not be null!");

		if (handler != null) {

			AuditingHandler object = handler.getObject();
			if (object != null) {
				object.markModified(target);
			}
		}
	}
}