/**
     * Returns {@literal true} if the parameter type of the constructor is parameterized.
     *
     * @param index
     *            The index of the parameter
     * @return {@literal true} if the parameter type is parameterized
     */
    boolean isParameterized(int index);

    /**
     * Returns an array of {@link ParameterizedClassDesc} representing the parameter types of the method.
     *

If you want to:

* declare the `q` query parameter without a `Query` nor any default value
* declare the path parameter `item_id` using `Path`
* have them in a different order
* not use `Annotated`

...Python has a little special syntax for that.

Pass `*`, as the first parameter of the function.

   * the dummy value of a constructor or method parameter is unknown.
   */
  @VisibleForTesting
  static final class ParameterNotInstantiableException extends Exception {
    public ParameterNotInstantiableException(Parameter parameter) {
      super(
          "Cannot determine value for parameter "
              + parameter
              + " of "
              + parameter.getDeclaringInvokable());
    }
  }

    /**
     * Set the value of level, used in parameter comment. <br>
     * Even if empty string, treated as empty plainly. So "IF pmb != null" is false if empty.
     * @param level The parameter value of level. (NotNull)
     */
    public void setLevel(String level) {
        registerVariable("level", level);
    }

    /**
     * Set the value of hostname, used in parameter comment. <br>

///

### Declare a *path parameter* { #declare-a-path-parameter }

Then create a *path parameter* with a type annotation using the enum class you created (`ModelName`):

{* ../../docs_src/path_params/tutorial005_py310.py hl[16] *}

### Check the docs { #check-the-docs }

Because the available values for the *path parameter* are predefined, the interactive docs can show them nicely:

    /** URL parameter associated with the error */
    public String url;

    /** Number of results parameter */
    public String num;

    /** Sort order parameter for search results */
    public String sort;

    /** Language parameter for search interface */
    public String lang;

    /**
     * Default constructor for ErrorForm.
     */
    public ErrorForm() {
        super();
    }

# Body - Multiple Parameters { #body-multiple-parameters }

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

# Query Parameter Models { #query-parameter-models }

If you have a group of **query parameters** that are related, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

 * types, and also for interfaces and public classes that have public parameter-less constructors.
 * When the non-null default value for a particular parameter type cannot be provided by {@code
 * NullPointerTester}, the caller can provide a custom non-null default value for the parameter type
 * via {@link #setDefault}.
 *
 * @author Kevin Bourrillion
 * @since 10.0
 */
@GwtIncompatible

    // for error page

    /**
     * Query string parameter for error page fallback.
     * Contains the original search query if redirection fails.
     */
    public String q;

    /**
     * Number of results parameter for error page fallback.
     * Specifies how many results to display if redirection fails.
     */
    public String num;

    /**
     * Sort parameter for error page fallback.