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Utilities for JPA, JDBC and DataSources
There is a newer version: 0.22.J1
/*
 * Copyright 2018 OmniFaces
 *
 * 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
 *
 *     http://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.omnifaces.persistence.model;

import java.io.Serializable;
import java.util.Objects;

import javax.persistence.EntityListeners;
import javax.persistence.MappedSuperclass;

import org.omnifaces.persistence.listener.BaseEntityListener;
import org.omnifaces.persistence.service.BaseEntityService;

/**
 * 
 * Let all your entities extend from this.
 * Then you can make use of {@link BaseEntityService}.
 * 

 * There are five more mapped superclasses which may also be of interest.
 * 

 * {@link TimestampedBaseEntity} - extends {@link BaseEntity} with created and lastModified columns and automatically takes care of them.
 * 
{@link VersionedBaseEntity} - extends {@link TimestampedBaseEntity} with a @Version column and automatically takes care of it.
 * 
{@link GeneratedIdEntity} - extends {@link BaseEntity} with id column and automatically takes care of it.
 * 
{@link TimestampedEntity} - extends {@link GeneratedIdEntity} with created and lastModified columns and automatically takes care of them.
 * 
{@link VersionedEntity} - extends {@link TimestampedEntity} with a @Version column and automatically takes care of it.
 * 
 *
 * @param  The generic ID type.
 * @author Bauke Scholtz
 */
@MappedSuperclass
@EntityListeners(BaseEntityListener.class)
public abstract class BaseEntity & Serializable> implements Comparable>, Identifiable, Serializable {

	private static final long serialVersionUID = 1L;

	/**
	 * Hashes by default the ID.
	 */
	@Override
    public int hashCode() {
        return (getId() != null)
        	? Objects.hash(getId())
        	: super.hashCode();
    }

	/**
	 * Compares by default by entity class (proxies taken into account) and ID.
	 */
	@Override
    public boolean equals(Object other) {
        return (getId() != null && getClass().isInstance(other) && other.getClass().isInstance(this))
            ? getId().equals(((BaseEntity) other).getId())
            : (other == this);
    }

	/**
	 * Orders by default with "nulls last".
	 */
	@Override
	public int compareTo(BaseEntity other) {
		return (other == null)
			? -1
			: (getId() == null)
				? (other.getId() == null ? 0 : 1)
				: getId().compareTo(other.getId());
	}

	/**
	 * The default format is ClassName[{id}] where {id} defaults to @hashcode when null.
	 */
	@Override
	public String toString() {
		return String.format("%s[%s]", getClass().getSimpleName(), (getId() != null) ? getId() : ("@" + hashCode()));
	}

}