"operationId": "read_items_items__get",
                    "security": [{"OAuth2AuthorizationCodeBearer": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {
                "OAuth2AuthorizationCodeBearer": {
                    "type": "oauth2",
                    "flows": {
                        "authorizationCode": {

/**
 * Denotes that a bean should be created as a singleton instance.
 * <p>
 * Singleton-scoped beans are instantiated once and reused throughout the entire
 * Maven execution. This scope should be used for stateless services or components
 * that can be safely shared across the entire build process.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Singleton
 * public class GlobalConfiguration {
 *     // Implementation
 * }
 * </pre>
 *

package org.apache.maven.cling.invoker.mvnenc.goals;

import java.io.IOException;

import org.apache.maven.api.services.MessageBuilderFactory;
import org.apache.maven.cling.invoker.mvnenc.Goal;
import org.codehaus.plexus.components.secdispatcher.SecDispatcher;

/**
 * The support class for goal implementations.
 */
public abstract class GoalSupport implements Goal {
    protected final MessageBuilderFactory messageBuilderFactory;

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"OpenIdConnect": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {
                "OpenIdConnect": {
                    "type": "openIdConnect",
                    "openIdConnectUrl": "/openid",

 * the fact that the problem reporter has/should not have information about the calling context and hence cannot provide
 * an expressive source hint for the model problem. Instead, the source hint is configured by the model builder before
 * it delegates to other components that potentially encounter problems. Then, the problem reporter can focus on

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"APIKeyQuery": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {
                "APIKeyQuery": {"type": "apiKey", "name": "key", "in": "query"}
            }
        },

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"HTTPDigest": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {"HTTPDigest": {"type": "http", "scheme": "digest"}}
        },

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"APIKeyCookie": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {
                "APIKeyCookie": {"type": "apiKey", "name": "key", "in": "cookie"}
            }
        },

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"HTTPBasic": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {"HTTPBasic": {"type": "http", "scheme": "basic"}}
        },

# Dependencies { #dependencies }

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

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 }