Himpunan unik di Scala

M4.java

public class M4 {
  private int posisi;
  private String asamAmino;

  public M4(int posisi, String asamAmino) {
    this.posisi = posisi;
    this.asamAmino = asamAmino;
  }

  public int getPosisi() {
    return posisi;
  }

  public String getAsamAmino() {
    return asamAmino;
  }

  @Override
  public int hashCode() {
    return posisi;
  }

  @Override
  public boolean equals(Object other) {
    if (other instanceof M4) {
      M4 m = (M4)other;
      return posisi == m.getPosisi() && asamAmino.equals(m.getAsamAmino());
    }
    return false;
  }

  @Override
  public String toString() {
    return posisi + asamAmino;
  }
}

TesUnik.scala

case class M1(val posisi: Int, val asamAmino: String)

class M2(val posisi: Int, val asamAmino: String) {
  override def toString() = "%d%s".format(posisi, asamAmino)
}

class M3(val posisi: Int, val asamAmino: String) {
  override def toString() = "%d%s".format(posisi, asamAmino)
  override def hashCode = posisi
  override def equals(other: Any) =
    if (other.isInstanceOf[M3]) {
      val m = other.asInstanceOf[M3]
      m.posisi == posisi && m.asamAmino == asamAmino
    } else false
}

object TesUnik extends App {
  println("-- M1")
  val list1 = List(M1(1, "a"), M1(2, "b"), M1(1, "c"), M1(3, "b"), M1(1, "a"))
  println(list1)
  println(list1.distinct)

  println("-- M2")
  val list2 = List(new M2(1, "a"), new M2(2, "b"), new M2(1, "c"), new M2(3, "b"), new M2(1, "a"))
  println(list2)
  println(list2.distinct)

  println("-- M3")
  val list3 = List(new M3(1, "a"), new M3(2, "b"), new M3(1, "c"), new M3(3, "b"), new M3(1, "a"))
  println(list3)
  println(list3.distinct)

  println("-- M4")
  val list4 = List(new M4(1, "a"), new M4(2, "b"), new M4(1, "c"), new M4(3, "b"), new M4(1, "a"))
  println(list4)
  println(list4.distinct)
}

/*

  Jalankan perintah berikut untuk mencoba:

  $ javac M4.java
  $ scalac TesUnik.scala
  $ scala TesUnik

*/