How to create private fields that my functions will return

Question

My class currently looks like:

class WebConfig(config: Config) {

  def this() {
     this(ConfigFactor.load())
  }

  def dbPort = config.getInt("mysql.port")

}

I don't like that when I call dbPort, it has to call and then cast the config each and every time.

So I want to create private fields and set them in the constructor, so then calling dbPort will simply return what a private field has.

How can I do this?

I tried creating a private var but I am getting this error:

 class WebConfig(config: Config) {
      private var _dbPort: Int
      def this() {
         this(ConfigFactor.load())

         _dbPort = config.getInt("mysql.port")
      }

      def dbPort: Int = _dbPort

    }

Error:

abstract member may not have private modifier

While this does not answer the question, doesn't declaring lazy val dbPort = config.getInt("mysql.port") do exactly what you are trying to implement? — Kulu Limpa
– Kulu Limpa, Commented Nov 19, 2014 at 14:08

bwroga · Accepted Answer · 2015-04-10 12:40:05Z

6

You are getting that error because your private variable is not initially assigned a value, so is treated as abstract, and abstract variables can't be private because they can not be accessed by the sub classes that are required to implement them.

To fix this you can assign a placeholder value to your variable like this:

private var _dbPort: Int = _

That being said, I think vptheron and kululimpa's suggestions are the way to go.

edited Apr 10, 2015 at 12:40

answered Nov 19, 2014 at 14:34

bwroga

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Comments

vptheron · Accepted Answer · 2014-11-19 14:07:20Z

2

Can't you just write this:

class WebConfig(config: Config) {

  def this() {
     this(ConfigFactor.load())
  }

  val dbPort = config.getInt("mysql.port")

}

It will only read the config parameter one time.

answered Nov 19, 2014 at 14:07

vptheron

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