BigDecimalと切り捨て その2

こういうやつです。小数 in BigDecimalにtoLongExactとかやると死ぬ。

scala> BigDecimal(5.55555).toIntExact
java.lang.ArithmeticException: Rounding necessary
  at java.math.BigDecimal.commonNeedIncrement(BigDecimal.java:4148)
  at java.math.BigDecimal.needIncrement(BigDecimal.java:4204)
  at java.math.BigDecimal.divideAndRound(BigDecimal.java:4112)
  at java.math.BigDecimal.setScale(BigDecimal.java:2452)
  at java.math.BigDecimal.longValueExact(BigDecimal.java:3090)
  at java.math.BigDecimal.intValueExact(BigDecimal.java:3147)
  at scala.math.BigDecimal.toIntExact(BigDecimal.scala:738)
  ... 33 elided
scala> BigDecimal(5.55555).toLongExact
java.lang.ArithmeticException: Rounding necessary
  at java.math.BigDecimal.commonNeedIncrement(BigDecimal.java:4148)
  at java.math.BigDecimal.needIncrement(BigDecimal.java:4204)
  at java.math.BigDecimal.divideAndRound(BigDecimal.java:4112)
  at java.math.BigDecimal.setScale(BigDecimal.java:2452)
  at java.math.BigDecimal.longValueExact(BigDecimal.java:3090)
  at scala.math.BigDecimal.toLongExact(BigDecimal.scala:745)
  ... 33 elided

scala> BigDecimal(5.55555).setScale(0, scala.math.BigDecimal.RoundingMode.CEILING)
res2: scala.math.BigDecimal = 6