@Test
public void testEndless() {
Cache<String, String> cache = new LRUCache<String, String>(0);
assertFalse(cache.isFull());
cache.put("1", "1");
assertEquals(1, cache.size());
assertFalse(cache.isFull());
cache.put("2", "2");
assertEquals(2, cache.size());
assertFalse(cache.isFull());
}
@Test
public void testPrune() {
Cache<String, String> cache = new LRUCache<String, String>(3);
cache.put("1", "1");
cache.put("2", "2");
cache.put("3", "3");
assertEquals(0, cache.prune());
assertEquals(3, cache.size());
cache.put("4", "4");
assertEquals(0, cache.prune());
assertEquals(3, cache.size());
}
@Test
public void testBoosting() {
Cache<String, String> cache = new LFUCache<>(3);
cache.put("1", "1");
cache.put("2", "2");
cache.put("3", "3");
cache.get("3");
cache.get("3");
cache.get("3");
cache.get("3");
cache.get("2");
cache.get("2");
cache.get("2");
cache.get("1");
cache.get("1");
assertEquals(3, cache.size());
cache.put("4", "4");
assertNull(cache.get("1")); // 1 is less frequent and it is out of cache
assertNotNull(cache.get("4")); // 4 is new and it is inside
cache.get("3");
cache.get("2");
// bad sequence
cache.put("5", "5");
cache.get("5"); // situation: 2(1), 3(2), 5(1) value(accessCount)
cache.put("4", "4");
cache.get("4"); // situation: 3(1), 4(1)
cache.put("5", "5");
cache.get("5"); // situation: 3(1), 4(1), 5(1)
cache.put("4", "4");
cache.get("4"); // situation: 4(1)
assertEquals(3, cache.size());
assertNull(cache.get("1"));
assertNull(cache.get("2"));
assertNotNull(cache.get("3"));
assertNotNull(cache.get("4"));
assertNotNull(cache.get("5"));
}
@Test
public void testCache2() {
Cache<String, String> cache = new LFUCache<>(3);
cache.put("1", "1");
cache.put("2", "2");
assertFalse(cache.isFull());
cache.put("3", "3");
assertTrue(cache.isFull());
assertNotNull(cache.get("3"));
assertNotNull(cache.get("3"));
assertNotNull(cache.get("3")); // boost usage of a 3
assertNotNull(cache.get("1"));
assertNotNull(cache.get("2"));
cache.put("4", "4"); // since this is LFU cache, 1 AND 2 will be removed, but not 3
assertNotNull(cache.get("3"));
assertNotNull(cache.get("4"));
assertEquals(2, cache.size());
}
