Scala - メソッド

gistfile1.scala

class Money(val amount: BigDecimal, val currency: Currency){

  def plus(other: Money) = {
    require(other.currency == currency) // falseだとIllegalArgumentException
    new Money(amount + other.amount, currency) // 最後の式で評価された値が戻り値
  }

  override def equals(obj: Any) = obj match { // 該当したcaseの=>の右側の式が評価され、その結果がmatch式の戻り値
    case that: Money => amount == that.amount && currency == other.currency
    case _ => false // defaultケースのようなもの
  }

  override def hashCode = amount.hashCode + currency.hashCode
  // override def hashCode = amount.## + currency.## でもよい
}