/*
 * SonarQube
 * Copyright (C) 2009-2017 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package util.selenium;

import java.util.NoSuchElementException;

public final class Optional<T> {
  private static final Optional<?> EMPTY = new Optional<>();

  private final T value;

  private Optional() {
    this.value = null;
  }

  public static <T> Optional<T> empty() {
    @SuppressWarnings("unchecked")
    Optional<T> t = (Optional<T>) EMPTY;
    return t;
  }

  private Optional(T value) {
    this.value = value;
  }

  public static <T> Optional<T> of(T value) {
    return new Optional<>(value);
  }

  public T get() {
    if (value == null) {
      throw new NoSuchElementException("No value present");
    }
    return value;
  }

  public boolean isPresent() {
    return value != null;
  }
}