cooldaemon's memo

scala + amqp の I/F 悩み中

結果を全て Either で返すと仮定すると下記となる

(connect(host = "localhost", username = "guest", password = "guest") { conn =>
  conn.channel { ch =>
    for {
      ex <- ch.declareExchange(name = "test.exchange", type = "direct").right
      q  <- ch.declareQueue(name = "test.queue").right
      br <- q.bind(exchange = ex, routingKey = "test").right
      pr <- ex.publish(routingKey = "test", payload = "Hello world!".getBytes).right
    } yield pr
  }
}) match {
  case Left(e) => println(e.getMessage)
  case _       =>
}

失敗は全て Exception で返すと仮定すると下記となる

try {
  connect(host = "localhost", username = "guest", password = "guest") { conn =>
    conn.channel { ch =>
      val ex = ch.declareExchange(name = "test.exchange", type = "direct")
      val q  = ch.declareQueue(name = "test.queue")
      q.bind(exchange = ex, routingKey = "test")
      ex.publish(routingKey = "test", payload = "Hello world!".getBytes)
    }
  }
} catch {
  case e: Exception => println(e.getMessage)
  case _ =>
}

見た目も使い勝手も変わらない気がする。Scala は、どちらの記述もサポートしているので、どちらを採用するのが良いのか、さっぱり解らない。