SmsMessage.java

@Entity
@Table(name = "sms_message", indexes = @Index(name = "idx_sms_msg_queue_polling_fields", columnList = "next_attempt_time"))
public class SmsMessage {
	@Id
	@Column(name = "id", nullable = false)
	@GeneratedValue
	private Long id;

	@Column(name = "uid", nullable = false, unique = true)
	private String uid; // app-assigned unique ID

	@Column(name = "from_address", nullable = false)
	private String fromAddress;

	@Column(name = "to_address", nullable = false)
	private String toAddress;

	@Column(name = "text", nullable = false)
	private String text;

	private QueueingState sendingState = new QueueingState();
  
  // ...
}