}

        public WitnessNotification getLastNotification() {
            return lastNotification;
        }
    }

    /**
     * Test witness client that allows injection of mock RPC client
     */
    private static class TestWitnessClient extends WitnessClient {

        public TestWitnessClient(InetAddress witnessServer, CIFSContext context, WitnessRpcClient rpcClient) {

### Dependency injection

FastAPI'ın inanılmaz derecede kullanımı kolay, fakat inanılmaz derecede güçlü <abbr title='"components", "resources", "services", "providers" olarak da bilinen'><strong>Dependency Injection </strong></abbr> sistemi var.

    /**
     * Fess configuration settings.
     */
    @Resource
    protected FessConfig fessConfig;

    /**
     * Default constructor for RequestHeaderService.
     * Initializes the service with dependency injection.
     */
    public RequestHeaderService() {
        // Default constructor
    }

    /**
     * Retrieves a paginated list of request headers based on the provided pager criteria.
     *

    }

    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(FessStandardTransformer.class);

    /**
     * Initializes the transformer after dependency injection.
     * Sets up the Fess configuration and data serializer components.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {

        }
    }

    public void test_searchEngineClient_injection() {
        // Test SearchEngineClient field injection
        ThumbnailGenerator generator = new ThumbnailGenerator();
        assertNull(generator.searchEngineClient);

        // After proper initialization, it should be injected

     */
    public FacetInfo() {
        // Default constructor
    }

    /**
     * Initializes the facet configuration from Fess configuration properties.
     * This method is called after dependency injection to load default facet settings.
     */
    @PostConstruct
    public void init() {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        if (StringUtil.isNotBlank(fessConfig.getQueryFacetFields())) {

# Classes as Dependencies { #classes-as-dependencies }

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example { #a-dict-from-the-previous-example }

In the previous example, we were returning a `dict` from our dependency ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

### Dependency Injection

FastAPI bevat een uiterst eenvoudig, maar uiterst krachtig <abbr title='ook bekend als "componenten", "bronnen", "diensten", "aanbieders"'><strong>Dependency Injection</strong></abbr> systeem.

* Zelfs dependencies kunnen dependencies hebben, waardoor een hiërarchie of **“graph” van dependencies** ontstaat.

* Wie man **Validierungseinschränkungen** wie `maximum_length` oder `regex` setzt.
* Ein sehr leistungsfähiges und einfach zu bedienendes System für **<abbr title="Dependency Injection – Einbringen von Abhängigkeiten: Auch bekannt als Komponenten, Ressourcen, Provider, Services, Injectables">Dependency Injection</abbr>**.
* Sicherheit und Authentifizierung, einschließlich Unterstützung für **OAuth2** mit **JWT-Tokens** und **HTTP-Basic**-Authentifizierung.

    /**
     * Default constructor.
     */
    public PopularWordHelper() {
        // Default constructor
    }

    /**
     * Initializes the PopularWordHelper after dependency injection.
     * Sets up the cache with configured size and expiration settings.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {