Class EntityBase

src/main/java/com/rocketpt/server/dto/entity/EntityBase.java:25–74

Base class for an entity, as explained in the book "Domain Driven Design". All entities in this project have an identity attribute with type Long and name id. Inspired by the DDD Sample project. @author Christoph Knabe @author plexpt @see <a href= "https://github.com/citerus/dddsample-core/blob/mas

 * @since 2017-03-06
 */
@Setter
@Getter
public abstract class EntityBase {

    /**
     * This identity field has the wrapper class type Long so that an entity which
     * has not been saved is recognizable by a null identity.
     */
    @TableId(type = IdType.AUTO)
    private Integer id;

    @Override
    public boolean equals(final Object object) {
        if (!(object instanceof EntityBase)) {
            return false;
        }
        if (!getClass().equals(object.getClass())) {
            return false;
        }
        final EntityBase that = (EntityBase) object;
        _checkIdentity(this);
        _checkIdentity(that);
        return this.id.equals(that.getId());
    }

    /**
     * Checks the passed entity, if it has an identity. It gets an identity only by
     * saving.
     *
     * @param entity the entity to be checked
     * @throws IllegalStateException the passed entity does not have the identity
     *                               attribute set.
     */
    private void _checkIdentity(final EntityBase entity) {
        if (entity.getId() == null) {
            throw new IllegalStateException("Comparison identity missing in entity: " + entity);
        }
    }

    @Override
    public int hashCode() {
        return Objects.hash(this.getId());
    }

    @Override
    public String toString() {
        return this.getClass().getSimpleName() + "<" + getId() + ">";
    }

}