Question

Java 7 has introduced automatic resource management:

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
  return br.readLine();
}

This will work with any class that implements java.lang.AutoClosable.

I know there are several examples of doing automatic resource management in Scala, including one demonstrated by Martin Odersky.

Is there any plan to add a language-level resource management to Scala, similar to Java’s try(...) { }?

Answer 1

In scala this can be added as a library. As a example scala-arm (https://github.com/jsuereth/scala-arm) from jsuereth:

Imperative Style:

// Copy input into output.
for(input <- managed(new java.io.FileInputStream("test.txt"); 
    output <- managed(new java.io.FileOutputStream("test2.txt")) {
  val buffer = new Array[Byte](512)
  while(input.read(buffer) != -1) {
    output.write(buffer);
  }
}

Monadic style

val first_ten_bytes = managed(new FileInputStream("test.txt")) map { 
   input =>
     val buffer = new Array[Byte](10)
     input.read(buffer)
     buffer
}

On the github page are some more examples