Scala example source code file (bug573.scala)

This example Scala source code file (bug573.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

after, before, before, dir, dir, dirx, linked, node, node, node0, node0

The Scala bug573.scala source code

package lampion.collections;

object DirX {
  abstract class Dir {
    def reverse : Dir;
  }
  object BEFORE extends Dir {
    def reverse = AFTER;
  }
  object AFTER  extends Dir {
    def reverse = BEFORE;
  }
}

import DirX._;

abstract class Linked {
  type Node <: Node0;
  
  abstract class Node0 {
    self: Node =>
    
  	var next : Node = _;
    var prev : Node = _;
    
    def get(dir : Dir) = if (dir == BEFORE) prev; else next;
    private def set(dir : Dir, node : Node) = 
      if (dir == BEFORE) prev = node; else next = node;

    def link(dir : Dir, node : Node) = {
      assert(get(dir) == null);
      assert(node.get(dir.reverse) == null);
      set(dir, node);
      node.set(dir.reverse, self);
    }

    
    def end(dir : Dir) : Node = {
      if (get(dir) == null) this;
      else get(dir).end(dir);
    }
  }
}