jakubjanecek

class ComplexNumber private (val x: Int, val y: Int) {
  
  def +(c: ComplexNumber) = ComplexNumber(x + c.x, y + c.y)

  def *(c: ComplexNumber) = ComplexNumber((x * c.x) - (y * c.y), (y * c.x) + (x * c.y))
  
  // higher-order method
  def transform(f: ComplexNumber => ComplexNumber) = f(this)

  override def toString = s"$x + ${y}i"

jakubjanecek

String value = getValueFromDb("key") // possibly null
if (value != null) {
    // continue
}

jakubjanecek

ev match {
  case Event(id, "event2", when, device) => println("'event2' from device " + device)
  case Event(id, name, when, device) if when > System.currentTimeMillis() - 10000 => println("fresh event")
  case _ => // ignore
}

jakubjanecek

if (ev.getName().equals("event2")) {
    System.out.println("'event2' from device " + ev.getSource());
} else if (ev.getWhen() > System.currentTimeMillis() - 10000) {
    System.out.println("fresh event");
} else {
    // ignore
}

jakubjanecek

def genericSize(obj: AnyRef): Int = obj match {
  case x: String => x.length
  case x: Array[AnyRef] => x.length
  case x: List[AnyRef] => x.size
  case x: ObjectWithSize => x.count
  case _ => -1
}

jakubjanecek

private static int genericSize(Object obj) {
    if (obj instanceof String) {
        String s = (String) obj;
        return s.length();
    } else if (obj instanceof int[]) {
        int[] a = (int[]) obj;
        return a.length;
    } else if (obj instanceof List) {
        List l = (List) obj;
        return l.size();

jakubjanecek

case class Event(id: Long, name: String, when: Long, source: EventSource)

jakubjanecek

public final class Event {

    private final long id;

    private final String name;

    private final long when;

    private final EventSource source;
    

jakubjanecek

val odds = collection.filter(n => n % 2 == 1)

jakubjanecek

List<Integer> odds = new ArrayList<Integer>();
for (int n : collectionOfNumbers) {
    if (n % 2 == 1) {
        odds.add(n);
    }
}