指定範囲内の日付をランダムに取得

rand_date.groovy

@Grab(group='joda-time', module='joda-time', version='*')
import org.joda.time.*

DateTime.metaClass.random ={t->
  def range = Days.daysBetween(delegate, new DateTime(t)).getDays() + 1
  delegate.plusDays(Math.floor(Math.random() * range) as int).toString("yyyy-MM-dd")
}

5.times{
    println new DateTime("1978-09-30").random("2011-10-10")
}