if m.handlers.hasSubhandler(subID) && !id.isTestHandler() {
		return fmt.Errorf("handler %v, subroute:%v: %w", id.String(), s, ErrHandlerAlreadyExists)
	}
	m.handlers.subSingle[subID] = h
	// Copy so clients can also pick it up for other subpaths.
	m.handlers.subSingle[makeZeroSubHandlerID(id)] = h
	return nil
}

/*
// RegisterStateless will register a stateless handler that serves
// []byte -> stream of ([]byte, error) requests.

        mimetypeMap.put(mimetype, filetype);
    }

    /**
     * Retrieves the file type for a given MIME type.
     *
     * @param mimetype the MIME type to look up
     * @return the corresponding file type, or the default value if not found
     */
    public String get(final String mimetype) {
        final String filetype = mimetypeMap.get(mimetype);

              + " map in that class.");
    }
    Object result;
    try {
      result = supplier.get();
    } catch (Throwable t) {
      if (predicate.apply(t)) {
        // We are careful to set up INSTANCE_OF to match each Predicate to its target Class.
        @SuppressWarnings("unchecked")
        T caught = (T) t;
        return caught;
      }
      throw new AssertionError(

              + " map in that class.");
    }
    Object result;
    try {
      result = supplier.get();
    } catch (Throwable t) {
      if (predicate.apply(t)) {
        // We are careful to set up INSTANCE_OF to match each Predicate to its target Class.
        @SuppressWarnings("unchecked")
        T caught = (T) t;
        return caught;
      }
      throw new AssertionError(

              + " map in that class.");
    }
    Object result;
    try {
      result = supplier.get();
    } catch (Throwable t) {
      if (predicate.apply(t)) {
        // We are careful to set up INSTANCE_OF to match each Predicate to its target Class.
        @SuppressWarnings("unchecked")
        T caught = (T) t;
        return caught;
      }
      throw new AssertionError(

              + " map in that class.");
    }
    Object result;
    try {
      result = supplier.get();
    } catch (Throwable t) {
      if (predicate.apply(t)) {
        // We are careful to set up INSTANCE_OF to match each Predicate to its target Class.
        @SuppressWarnings("unchecked")
        T caught = (T) t;
        return caught;
      }
      throw new AssertionError(

<img src="/img/tutorial/path-operation-configuration/image01.png">

### Tags with Enums { #tags-with-enums }

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

        // Add entries
        statusMap.put(CrawlerStatus.INITIALIZING, "Starting up");
        statusMap.put(CrawlerStatus.RUNNING, "In progress");
        statusMap.put(CrawlerStatus.DONE, "Completed");

        // Verify entries
        assertEquals(3, statusMap.size());
        assertEquals("Starting up", statusMap.get(CrawlerStatus.INITIALIZING));

    /**
     * The date of publication of the article.
     * The date must be in W3C format.
     */
    private String publicationDate;

    /**
     * The title of the news article.
     * The title may be up to 110 characters.
     */
    private String title;

    /**
     * A comma-separated list of keywords describing the topic of the article.

        mockContext = mock(CIFSContext.class);
        mockConfig = mock(Configuration.class);
        mockCredentials = mock(Credentials.class);
        mockTransportPool = mock(SmbTransportPool.class);

        // Set up mock behaviors
        when(mockContext.getConfig()).thenReturn(mockConfig);
        when(mockContext.getCredentials()).thenReturn(mockCredentials);
        when(mockContext.getTransportPool()).thenReturn(mockTransportPool);