LibTest/collection/SplayTreeMap/SplayTreeMap_class_A05_t02.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)])
/// To allow calling operator[], [remove] or [containsKey] with objects that are
/// not supported by the [compare] function, an extra [isValidKey] predicate
/// function can be supplied. This function is tested before using the [compare]
/// function on an argument value that may not be a [K] value.
/// @description Checks that if [isValidKey] supplied and returns [false] then
/// element is assumed not to be in a map
/// @author sgrekhov@unipro.ru

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

class C {
  int value;
  C(this.value);
}

int compare(var key1, var key2) {
  return key1.value - key2.value;
}

bool isValidKey(var potentialKey) => potentialKey.value != 3;

main() {
  SplayTreeMap map = new SplayTreeMap(compare, isValidKey);
  C c1 = new C(1);
  C c2 = new C(2);
  C c3 = new C(3);

  map[c1] = 1;
  map[c2] = 2;
  map[c3] = 3;

  Expect.equals(3, map.length);
  Expect.isNull(map[c3]);
  Expect.isFalse(map.containsKey(c3));
  Expect.isNull(map.remove(c3));
}