# 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 }

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.plugin;

import org.apache.maven.model.Plugin;
import org.codehaus.plexus.component.composition.CycleDetectedInComponentGraphException;

/**
 * Exception occurring trying to resolve a plugin.
 *
 */
public class CycleDetectedInPluginGraphException extends Exception {
    private final Plugin plugin;

<component name="DependencyValidationManager">
    <!-- The source of truth for this pattern is `build-logic/basics/src/main/kotlin/gradlebuild/basics/PublicApi.kt` file, please keep them in sync -->
    <scope name="Gradle public API"

import org.apache.maven.api.di.Named;
import org.apache.maven.api.di.Singleton;
import org.apache.maven.api.services.MessageBuilderFactory;
import org.apache.maven.cling.invoker.mvnenc.EncryptContext;
import org.codehaus.plexus.components.secdispatcher.SecDispatcher;

import static org.apache.maven.cling.invoker.mvnenc.EncryptInvoker.OK;

/**
 * The "encrypt" goal.
 */
@Singleton
@Named("encrypt")

                    "operationId": "read_current_user_users_me_get",
                    "security": [{"HTTPBase": []}],
                }
            }
        },
        "components": {
            "securitySchemes": {
                "HTTPBase": {
                    "type": "http",
                    "scheme": "Other",
                    "description": "Other Security Scheme",
                }

     */

    if (isFinalPart && DIGIT_MATCHER.matches(part.charAt(0))) {
      return false;
    }

    return true;
  }

  /**
   * Returns the individual components of this domain name, normalized to all lower case. For
   * example, for the domain name {@code mail.google.com}, this method returns the list {@code
   * ["mail", "google", "com"]}.
   */

import org.apache.maven.api.di.Named;
import org.apache.maven.api.di.Singleton;
import org.apache.maven.api.services.MessageBuilderFactory;
import org.apache.maven.cling.invoker.mvnenc.EncryptContext;
import org.codehaus.plexus.components.secdispatcher.SecDispatcher;

import static org.apache.maven.cling.invoker.mvnenc.EncryptInvoker.OK;

/**
 * The "diag" goal. It should always run, despite it overrides configured goal support.
 */
@Singleton

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

 */
package org.apache.maven.artifact;

import org.codehaus.plexus.component.repository.exception.ComponentLookupException;

/**
 * Exception which is meant to occur when a layout specified for a particular
 * repository doesn't have a corresponding {@link org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout}
 * component in the current container.
 *
 */
@Deprecated

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