content: /*
   * This file is a part of BSL Language Server.
   *
   * Copyright (c) 2018-2025
   * Alexey Sosnoviy <labotamy@gmail.com>, Nikita Fedkin <nixel2007@gmail.com> and contributors
   *
   * SPDX-License-Identifier: LGPL-3.0-or-later
   *
   * BSL Language Server 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 3.0 of the License, or (at your option) any later version.
   *
   * BSL Language Server 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 BSL Language Server.
   */
  /*
   * Originally authored by Ilkka Seppälä with the MIT License:
   *
   * The MIT License
   * Copyright © 2014-2019 Ilkka Seppälä
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  package com.github._1c_syntax.bsl.languageserver.utils;
  
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * Generic object pool.
   *
   * @param <T> Type T of Object in the Pool
   */
  public abstract class AbstractObjectPool<T> {
  
    private final Set<T> available = new HashSet<>();
    private final Set<T> inUse = new HashSet<>();
  
    protected abstract T create();
  
    /**
     * Checkout object from pool.
     */
    public synchronized T checkOut() {
      if (available.isEmpty()) {
        available.add(create());
      }
      T instance = available.iterator().next();
      available.remove(instance);
      inUse.add(instance);
      return instance;
    }
  
    public synchronized void checkIn(T instance) {
      inUse.remove(instance);
      available.add(instance);
    }
  
    @Override
    public synchronized String toString() {
      return String.format("Pool available=%d inUse=%d", available.size(), inUse.size());
    }
  }
  