Scala Design Patterns - Second Edition

Code example

Now, let's have a closer look at the code that implements the preceding class diagram. The first thing we need to define is the interface (using a Scala trait):

trait FileReader {  def readFileContents(): String}

We then create two classes that implement it—FileReaderReal and FileReaderProxy. First, let's see how the former implements the file read as it has nothing of real significance:

class FileReaderReal(filename: String) extends FileReader {  val contents = {    val stream = this.getClass.getResourceAsStream(filename)    val reader = new BufferedReader(      new InputStreamReader(        stream      )    )    try {      reader.lines().iterator().asScala.mkString      (System.getProperty("line.separator"))    } finally {      reader.close()      stream.close()    }  }  System.out ...