@MappedSuperclass
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
abstract public class BasicPersistentObject implements Creatable, Updatable,
      UpdatedBy, CreatedBy, Serializable {

   @ManyToOne(fetch = FetchType.LAZY)
   private User updatedBy;

   @ManyToOne(fetch = FetchType.LAZY)
   private User createdBy;

   @Column(name = "createdBy_id", insertable = false, updatable = false)
   private String createdById;

   @NotNull
   private Date createdDate;

   @NotNull
   private Date updatedDate;

   public Date getCreatedDate() {
      return createdDate;
   }

   public void setCreatedDate(Date createdDate) {
      this.createdDate = createdDate;
   }

   public Date getUpdatedDate() {
      return updatedDate;
   }

   public void setUpdatedDate(Date updatedDate) {
      this.updatedDate = updatedDate;
   }

   public boolean isNew() {
      return createdDate == null;
   }

   public User getUpdatedBy() {
      return updatedBy;
   }

   public void setUpdatedBy(User updatedBy) {
      this.updatedBy = updatedBy;
   }

   public User getCreatedBy() {
      return createdBy;
   }

   public void setCreatedBy(User createdBy) {
      this.createdBy = createdBy;
      this.createdById = createdBy.getId();
   }

   public String getCreatedById() {
      return createdById;
   }

   public void setCreatedById(String createdById) {
      this.createdById = createdById;
   }

}


@MappedSuperclass
abstract public class PersistentObject extends BasicPersistentObject {

   @Id
   @Length(min = 36, max = 36)
   @Column(columnDefinition = "CHAR (36)")
   private String id = UUID.randomUUID().toString();

   public String getId() {
      return id;
   }

   public void setId(String id) {
      this.id = id;
   }

   public boolean equals(Object o) {
      if (this == o)
         return true;
      if (o == null || !(o instanceof PersistentObject)) {

         return false;
      }

      PersistentObject other = (PersistentObject) o;

      // if the id is missing, return false
      if (id == null)
         return false;

      // equivalence by id
      return id.equals(other.getId());
   }

   public int hashCode() {
      if (id != null) {
         return id.hashCode();
      } else {
         return super.hashCode();
      }
   }

   public String toString() {
      return this.getClass().getName() + "[id=" + id + "]";
   }
}


@Entity
public class Comment extends PersistentObject {

   /**
    * The parent Id that owns this thread of comments.
    */
   @NotNull
   @Column(columnDefinition = "CHAR (36)")
   private String parentId;

   @Column(length = 2000)
   @NotNull
   private String comment;

   @ManyToOne
   private Comment parentComment;

   @ManyToOne
   @JoinColumns( {
         @JoinColumn(name = "parentId", referencedColumnName = "parentId", updatable = false, insertable = false),
         @JoinColumn(name = "createdBy_id", referencedColumnName = "createdBy_id", updatable = false, insertable = false) })
   private Review review;

   @Length(max = 24)
   private String ipAddress;

   public String getIpAddress() {
      return ipAddress;
   }

   public void setIpAddress(String ipAddress) {
      this.ipAddress = ipAddress;
   }

   public Comment getParentComment() {
      return parentComment;
   }

   public void setParentComment(Comment parentComment) {
      this.parentComment = parentComment;
   }

   public String getParentId() {
      return parentId;
   }

   public void setParentId(String parentId) {
      this.parentId = parentId;
   }

   public String getComment() {
      return comment;
   }

   public void setComment(String comment) {
      this.comment = comment;
   }

   public Review getReview() {
      return review;
   }

   public void setReview(Review review) {
      this.review = review;
   }

}


@Entity
@Table(uniqueConstraints = { @UniqueConstraint(columnNames = { "parentId",
      "createdBy_id" }) })
public class Review extends PersistentObject {

   @NotNull
   @Length(min = 36, max = 36)
   @Column(columnDefinition = "CHAR (36)")
   private String parentId;

   @NotNull
   private Integer rating1 = 0;

   @NotNull
   private Integer rating2 = 0;

   @NotNull
   private Integer rating3 = 0;

   @NotNull
   private Integer rating4 = 0;

   @NotNull
   private Integer rating5 = 0;

   public String getParentId() {
      return parentId;
   }

   public void setParentId(String parentId) {
      this.parentId = parentId;
   }

   public Integer getRating1() {
      return rating1;
   }

   public void setRating1(Integer rating1) {
      this.rating1 = rating1;
   }

   public Integer getRating2() {
      return rating2;
   }

   public void setRating2(Integer rating2) {
      this.rating2 = rating2;
   }

   public Integer getRating3() {
      return rating3;
   }

   public void setRating3(Integer rating3) {
      this.rating3 = rating3;
   }

   public Integer getRating4() {
      return rating4;
   }

   public void setRating4(Integer rating4) {
      this.rating4 = rating4;
   }

   public Integer getRating5() {
      return rating5;
   }

   public void setRating5(Integer rating5) {
      this.rating5 = rating5;
   }

}