It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

@Documented
public @interface Typed {
    /**
     * Specifies the types that should be considered for dependency injection.
     * <p>
     * When specified, only the listed types will be available for injection,
     * even if the class implements or extends other types. If empty, the
     * default behavior is to make all supertypes available for injection.
     * <p>
     * Example:
     * <pre>
     * {@literal @}Typed({Service.class, Monitored.class})

 * <p>
 * Key features include:
 * <ul>
 *   <li>Constructor, method, and field injection</li>
 *   <li>Qualifiers for distinguishing between beans of the same type</li>
 *   <li>Multiple scopes (Singleton, Session, and MojoExecution)</li>
 *   <li>Priority-based implementation selection</li>
 *   <li>Type-safe dependency injection</li>
 * </ul>
 *
 * @since 4.0.0
 */

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Marks a dependency injection point for constructor, method, or field injection.
 * <p>
 * This annotation is used to identify injection points where the container should
 * provide an instance of the requested type. It can be applied to:
 * <ul>
 *   <li>Constructors</li>
 *   <li>Methods</li>

 * of the same type are available.
 * <p>
 * Higher values indicate higher priority. When multiple implementations of the same
 * type exist, the one with the highest priority will be selected for injection.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Priority(100)
 * public class PreferredImplementation implements Service {
 *     // Implementation
 * }
 * </pre>
 *
 * @since 4.0.0
 */

## Codegröße

Dieses Beispiel mag ausführlich erscheinen. Bedenken Sie, dass wir Sicherheit, Datenmodelle, Hilfsfunktionen und *Pfadoperationen* in derselben Datei vermischen.

Aber hier ist der entscheidende Punkt.

Der Code für Sicherheit und Dependency Injection wird einmal geschrieben.

## Code size { #code-size }

This example might seem verbose. Keep in mind that we are mixing security, data models, utility functions and *path operations* in the same file.

But here's the key point.

The security and dependency injection stuff is written once.

import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Marks a method as a provider of beans for dependency injection.
 * <p>
 * This annotation can be used on static methods to programmatically create and configure
 * beans that will be managed by the dependency injection container. It's particularly
 * useful when the bean creation requires complex logic or when the bean needs to be

    <artifactId>maven-api</artifactId>
    <version>4.1.0-SNAPSHOT</version>
  </parent>

  <artifactId>maven-api-di</artifactId>
  <name>Maven 4 API :: Dependency Injection</name>
  <description>Maven 4 API - Dependency Injection</description>

  <properties>
    <maven.compiler.proc>none</maven.compiler.proc>
  </properties>

     */
    public RelatedQueryHelper() {
        super();
    }

    /**
     * Initializes the RelatedQueryHelper after dependency injection is complete.
     * This method is called automatically by the dependency injection framework
     * and loads the initial related query configurations.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {