LibTest/collection/SplayTreeMap/SplayTreeMap_class_A04_t03.dart

// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// @dart = 2.9

/// @assertion SplayTreeMap([int compare(K key1, K key2),
/// bool isValidKey(potentialKey)])
/// ...
/// Keys of the map are compared using the compare function passed in the
/// constructor, both for ordering and for equality.
/// If the [compare] function is omitted, the objects are assumed to be
/// [Comparable], and are compared using their [Comparable.compareTo] method.
/// Non-comparable objects (including [null]) will not work as keys in that case.
/// @description Checks that if compare function is not specified then key object
/// should implement comparable.
/// @author sgrekhov@unipro.ru

import "dart:collection";
import "../../../Utils/expect.dart";

class C implements Comparable {
  int value;
  C(this.value);

  compareTo(Object other) {
    return this.value - (other as C).value;
  }
}

main() {
  SplayTreeMap map = new SplayTreeMap();
  C c1 = new C(2);
  C c2 = new C(1);

  map[c1] = 1;
  map[c2] = 2;

  Expect.equals(c2, map.firstKey());
  Expect.equals(c1, map.lastKey());
}