Authenticator (Java SE 9 & JDK 9 )

java.lang.Object
- com.sun.net.httpserver.Authenticator

Direct Known Subclasses:

BasicAuthenticator
```
public abstract class Authenticator
extends Object
```
Authenticator represents an implementation of an HTTP authentication mechanism. Sub-classes provide implementations of specific mechanisms such as Digest or Basic auth. Instances are invoked to provide verification of the authentication information provided in all incoming requests. Note. This implies that any caching of credentials or other authentication information must be done outside of this class.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`Authenticator.Failure`	Indicates an authentication failure.
`static class`	`Authenticator.Result`	Base class for return type from authenticate() method
`static class`	`Authenticator.Retry`	Indicates an authentication must be retried.
`static class`	`Authenticator.Success`	Indicates an authentication has succeeded and the authenticated user principal can be acquired by calling getPrincipal().

Constructor Summary

Constructors
Constructor Description

Authenticator()

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract Authenticator.Result`	`authenticate(HttpExchange exch)`	called to authenticate each incoming request.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Authenticator
```
public Authenticator()
```
- Method Detail
  - authenticate
```
public abstract Authenticator.Result authenticate(HttpExchange exch)
```
    called to authenticate each incoming request. The implementation must return a Failure, Success or Retry object as appropriate :-
    Failure means the authentication has completed, but has failed due to invalid credentials.
    Sucess means that the authentication has succeeded, and a Principal object representing the user can be retrieved by calling Sucess.getPrincipal() .
    Retry means that another HTTP exchange is required. Any response headers needing to be sent back to the client are set in the given HttpExchange. The response code to be returned must be provided in the Retry object. Retry may occur multiple times.