java-design-patterns/object-pool/src/test/java/com/iluwatar/object/pool/OliphauntPoolTest.java

/*
 * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
 *
 * The MIT License
 * Copyright © 2014-2022 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.iluwatar.object.pool;

import static java.time.Duration.ofMillis;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotSame;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTimeout;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.util.List;
import org.junit.jupiter.api.Test;

/**
 * OliphauntPoolTest.
 */
class OliphauntPoolTest {

  /**
   * Use the same object 100 times subsequently. This should not take much time since the heavy
   * object instantiation is done only once. Verify if we get the same object each time.
   */
  @Test
  void testSubsequentCheckinCheckout() {
    assertTimeout(ofMillis(5000), () -> {
      final var pool = new OliphauntPool();
      assertEquals("Pool available=0 inUse=0", pool.toString());

      final var expectedOliphaunt = pool.checkOut();
      assertEquals("Pool available=0 inUse=1", pool.toString());

      pool.checkIn(expectedOliphaunt);
      assertEquals("Pool available=1 inUse=0", pool.toString());

      for (int i = 0; i < 100; i++) {
        final var oliphaunt = pool.checkOut();
        assertEquals("Pool available=0 inUse=1", pool.toString());
        assertSame(expectedOliphaunt, oliphaunt);
        assertEquals(expectedOliphaunt.getId(), oliphaunt.getId());
        assertEquals(expectedOliphaunt.toString(), oliphaunt.toString());

        pool.checkIn(oliphaunt);
        assertEquals("Pool available=1 inUse=0", pool.toString());
      }
    });
  }

  /**
   * Use the same object 100 times subsequently. This should not take much time since the heavy
   * object instantiation is done only once. Verify if we get the same object each time.
   */
  @Test
  void testConcurrentCheckinCheckout() {
    assertTimeout(ofMillis(5000), () -> {
      final var pool = new OliphauntPool();
      assertEquals(pool.toString(), "Pool available=0 inUse=0");

      final var firstOliphaunt = pool.checkOut();
      assertEquals(pool.toString(), "Pool available=0 inUse=1");

      final var secondOliphaunt = pool.checkOut();
      assertEquals(pool.toString(), "Pool available=0 inUse=2");

      assertNotSame(firstOliphaunt, secondOliphaunt);
      assertEquals(firstOliphaunt.getId() + 1, secondOliphaunt.getId());

      // After checking in the second, we should get the same when checking out a new oliphaunt ...
      pool.checkIn(secondOliphaunt);
      assertEquals(pool.toString(), "Pool available=1 inUse=1");

      final var oliphaunt3 = pool.checkOut();
      assertEquals(pool.toString(), "Pool available=0 inUse=2");
      assertSame(secondOliphaunt, oliphaunt3);

      // ... and the same applies for the first one
      pool.checkIn(firstOliphaunt);
      assertEquals(pool.toString(), "Pool available=1 inUse=1");

      final var oliphaunt4 = pool.checkOut();
      assertEquals(pool.toString(), "Pool available=0 inUse=2");
      assertSame(firstOliphaunt, oliphaunt4);

      // When both oliphaunt return to the pool, we should still get the same instances
      pool.checkIn(firstOliphaunt);
      assertEquals(pool.toString(), "Pool available=1 inUse=1");

      pool.checkIn(secondOliphaunt);
      assertEquals(pool.toString(), "Pool available=2 inUse=0");

      // The order of the returned instances is not determined, so just put them in a list
      // and verify if both expected instances are in there.
      final var oliphaunts = List.of(pool.checkOut(), pool.checkOut());
      assertEquals(pool.toString(), "Pool available=0 inUse=2");
      assertTrue(oliphaunts.contains(firstOliphaunt));
      assertTrue(oliphaunts.contains(secondOliphaunt));
    });
  }


}