import org.apache.hadoop.oncrpc.RpcCallCache.ClientRequest; //导入依赖的package包/类
@Test
public void testCacheFunctionality() throws UnknownHostException {
  RpcCallCache cache = new RpcCallCache("Test", 10);
  
  // Add 20 entries to the cache and only last 10 should be retained
  int size = 0;
  for (int clientId = 0; clientId < 20; clientId++) {
    InetAddress clientIp = InetAddress.getByName("1.1.1."+clientId);
    System.out.println("Adding " + clientIp);
    cache.checkOrAddToCache(clientIp, 0);
    size = Math.min(++size, 10);
    System.out.println("Cache size " + cache.size());
    assertEquals(size, cache.size()); // Ensure the cache size is correct
    
    // Ensure the cache entries are correct
    int startEntry = Math.max(clientId - 10 + 1, 0);
    Iterator<Entry<ClientRequest, CacheEntry>> iterator = cache.iterator();
    for (int i = 0; i < size; i++) {
      ClientRequest key = iterator.next().getKey();
      System.out.println("Entry " + key.getClientId());
      assertEquals(InetAddress.getByName("1.1.1." + (startEntry + i)),
          key.getClientId());
    }
    
    // Ensure cache entries are returned as in progress.
    for (int i = 0; i < size; i++) {
      CacheEntry e = cache.checkOrAddToCache(
          InetAddress.getByName("1.1.1." + (startEntry + i)), 0);
      assertNotNull(e);
      assertTrue(e.isInProgress());
      assertFalse(e.isCompleted());
    }
  }
}