"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

**FastAPI** provides several tools to help you deal with **Security** easily, rapidly, in a standard way, without having to study and learn all the security specifications.

But first, let's check some small concepts.

## In a hurry?

If you don't care about any of these terms and you just need to add security with authentication based on username and password *right now*, skip to the next chapters.

## OAuth2

 *
 * @author Dimitris Andreou
 * @since 13.0
 */
// TODO(user): switch to nano precision. A natural unit of cost is "bytes", and a micro precision
// would mean a maximum rate of "1MB/s", which might be small in some cases.
@Beta
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class RateLimiter {
  /**

            return entity;
        });
    }

    // ===================================================================================
    //                                                                        Small Helper
    //                                                                        ============
    protected void verifyCrudMode(final int crudMode, final int expectedMode, final String dictId) {

   changing `.java` files.

 * **Kotlin source compatibility** is the ability to upgrade Kotlin uses of OkHttp 3.x to 4.x
   without changing `.kt` files.

With a few small exceptions (below), OkHttp 4.x is both binary- and Java source-compatible with
OkHttp 3.x. You can use an OkHttp 4.x .jar file with applications or libraries built for OkHttp 3.x.

        "The system cannot find the file specified.", "The system cannot find the file specified.", "End of file", "More data is available.",
        "Access is denied.", "The data area passed to a system call is too small.",
        "The filename, directory name, or volume label syntax is incorrect.", "The system cannot find the file specified.",

```

////

## Order the parameters as you need, tricks

/// tip

This is probably not as important or necessary if you use `Annotated`.

///

Here's a **small trick** that can be handy, but you won't need it often.

If you want to:

* declare the `q` query parameter without a `Query` nor any default value
* declare the path parameter `item_id` using `Path`

   * href="http://mathworld.wolfram.com/PrimeNumber.html">prime number</a>: an integer <i>greater
   * than one</i> that cannot be factored into a product of <i>smaller</i> positive integers.
   * Returns {@code false} if {@code n} is zero, one, or a composite number (one which <i>can</i> be
   * factored into smaller positive integers).
   *
   * <p>To test larger numbers, use {@link BigInteger#isProbablePrime}.
   *

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR