import java.util.Queue;
import java.util.concurrent.Executor;
import java.util.logging.Level;

/**
 * A list of listeners for implementing a concurrency friendly observable object.
 *
 * <p>Listeners are registered once via {@link #addListener} and then may be invoked by {@linkplain
 * #enqueue enqueueing} and then {@linkplain #dispatch dispatching} events.
 *

    checkArgument(
        !DEFAULTS.containsKey(type), "A default value was already registered for %s", type);
    checkArgument(
        implementations.put(type, implementation) == null,
        "Implementation for %s was already registered",
        type);
  }

  static {
    setImplementation(Appendable.class, StringBuilder.class);

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

### Application Interceptors

Interceptors are registered as either _application_ or _network_ interceptors. We'll use the `LoggingInterceptor` defined above to show the difference.

Register an _application_ interceptor by calling `addInterceptor()` on `OkHttpClient.Builder`:

 * close()}).
 *
 * <p>This pattern ensures the following:
 *
 * <ul>
 *   <li>Each {@code Closeable} resource that is successfully registered will be closed later.
 *   <li>If a {@code Throwable} is thrown in the try block, no exceptions that occur when attempting
 *       to close resources will be thrown from the finally block. The throwable from the try block

  /**
   * Map generator that verifies that {@code setUp()} methods are called in all the test cases. The
   * {@code setUpRan} parameter is set true by the {@code setUp} that every test case is supposed to
   * have registered, and set false by the {@code tearDown}. We use a dynamic proxy to intercept all
   * of the {@code Map} method calls and check that {@code setUpRan} is true.
   */

 *   <li>Dependency injection using {@code @Resource} annotation</li>
 *   <li>Lifecycle management using {@code @PostConstruct} and {@code @PreDestroy} annotations</li>
 * </ul>
 *
 * <p>Components can be registered in two ways:
 * <ul>
 *   <li>As singletons, where one instance is shared throughout the container's lifecycle</li>
 *   <li>As prototypes, where a new instance is created each time the component is requested</li>
 * </ul>

labels.user_x121Address=x121Address
labels.x121Address=x121Address
labels.user_businessCategory=Business Category
labels.businessCategory=Business Category
labels.user_registeredAddress=Registered Address
labels.registeredAddress=Registered Address
labels.user_displayName=Display Name
labels.displayName=Display Name
labels.user_preferredLanguage=Preferred Language
labels.preferredLanguage=Preferred Language

  /**
   * <a href="http://en.wikipedia.org/wiki/Embedded_OpenType">Embedded OpenType</a> fonts. This is
   * <a href="http://www.iana.org/assignments/media-types/application/vnd.ms-fontobject">registered
   * </a> with the IANA.
   *
   * @since 17.0
   */
  public static final MediaType EOT = createConstant(APPLICATION_TYPE, "vnd.ms-fontobject");

  /**

   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks
   * may execute concurrently, and listeners may execute in an order different from the one in which
   * they were registered.
   *
   * <p>RuntimeExceptions thrown by a listener will be caught and logged. Any exception thrown
   * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException}) will be caught and
   * logged.

        // Test bots with special characters - should be normalized to lowercase
        assertFalse(robotsTxt.allows("/trademark/", "Bot™"));
        assertFalse(robotsTxt.allows("/registered/", "Bot®"));

        // Test wildcard user-agent
        assertFalse(robotsTxt.allows("/default/", "UnknownRandomBot"));
    }

    public void testParse_emptyFile() {
        RobotsTxt robotsTxt;