![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java
class PrintingEventListener extends EventListener {
  private long callStartNanos;

  private void printEvent(String name) {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.IOException;
import java.util.concurrent.TimeUnit;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class PerCallSettings {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.IOException;
import okhttp3.Credentials;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class PreemptiveAuth {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.IOException;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Headers;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import java.io.IOException;
import java.util.Map;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes.kt

import java.io.File
import java.io.IOException
import okhttp3.Cache
import okhttp3.OkHttpClient
import okhttp3.Request

class CacheResponse(
  cacheDirectory: File,
) {

   */
  open fun cacheConditionalHit(
    call: Call,
    cachedResponse: Response,
  ) {
  }

  /**
   * Invoked when OkHttp decides whether to retry after a connectivity failure.
   *
   * OkHttp won't retry when it is configured not to:
   *
   *  * If retries are forbidden with [OkHttpClient.retryOnConnectionFailure]. (OkHttp's defaults

        }
        verifyNoInteractions(mockDir);
    }

    /**
     * Edge: passing a null directory object. Interface allows null; implementation decides.
     */
    @Test
    @DisplayName("null directory is handled by implementation")
    void handlesNullDirectory() throws Exception {
        SmbFilenameFilter filter = (dir, name) -> dir == null;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.IOException;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import okhttp3.Call;
import okhttp3.OkHttpClient;

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.File;
import java.io.IOException;
import okhttp3.Cache;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class CacheResponse {