Question

I have a model called Booking which has a persistent DateTime field. However I do not want to interact directly with this field, but rather through two Transient String fields, date and time. The problem is that I have no idea how/when play loads the data into the fields – it doesn’t seem to be using the constructor I provide because the DateTime field is always null.

public class Booking extends Model {

  @Column
  @Type(type="org.joda.time.contrib.hibernate.PersistentDateTime")
  public DateTime datetime;
  public Integer duration;
  @Transient
  public String date = "1970-01-01";
  @Transient
  public String time = "00:00";

  public Booking(String date, String time, Integer duration) {
    this.datetime = toDateTime(date, time);
    this.duration = duration;
  }

  public void setDate(String dateStr) {
    this.date = dateStr;
    this.datetime = toDateTime(dateStr, this.time);
  }

  public void setTime(String timeStr) {
    this.time = timeStr;
    this.datetime = toDateTime(this.date, timeStr);
  }

  public String getDate() {
    DateTimeFormatter format = DateTimeFormat.forPattern("yyyy-MM-dd");
    return this.datetime.toString(format); //NullPointerException here!
  }

  public String getTime() {
    DateTimeFormatter format = DateTimeFormat.forPattern("kk:mm");
    return this.datetime.toString(format);//NullPointerException here!
  }

here’s the toDateTime method:

  private DateTime toDateTime(String date, String time){
    DateTimeFormatter fmt = ISODateTimeFormat.dateHourMinute();
    DateTime dt = fmt.parseDateTime(date+"T"+time);

    return dt;
  }

Answer 1

It appears that you can define a default constructor that takes no parameters to set up your object when JPA loads it. Like so:

public Booking() {
  DateTimeFormatter fmt = ISODateTimeFormat.dateHourMinute();
  this.datetime = fmt.parseDateTime("1970-01-01T00:00");
}

Now the only problem is that it uses the same setters I’ve defined when retrieving from the database: *Caused by: java.lang.IllegalArgumentException: Invalid format: “ISO8601:2011-08-25T02:00:00+0200…”
*