content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.security.authentication;
  
  import alluxio.conf.AlluxioConfiguration;
  import alluxio.conf.PropertyKey;
  import alluxio.security.authentication.plain.CustomAuthenticationProvider;
  import alluxio.security.authentication.plain.PlainSaslServer;
  import alluxio.security.authentication.plain.PlainSaslServerCallbackHandler;
  import alluxio.security.authentication.plain.SimpleAuthenticationProvider;
  
  import javax.security.sasl.AuthenticationException;
  
  /**
   * Abstraction for an authentication provider at SASL server for
   * {@link AuthType#SIMPLE} and {@link AuthType#CUSTOM}.
   */
  public interface AuthenticationProvider {
  
    /**
     * Factory for {@link AuthenticationProvider}.
     */
    class Factory {
  
      // prevent instantiation
      private Factory() {}
  
      /**
       * @param authType authentication type to use
       * @return the generated {@link AuthenticationProvider}
       * @throws AuthenticationException when unsupported authentication type is used
       */
      public static AuthenticationProvider create(AuthType authType, AlluxioConfiguration conf)
          throws AuthenticationException {
        switch (authType) {
          case SIMPLE:
            return new SimpleAuthenticationProvider();
          case CUSTOM:
            Class<?> customProviderName =
                conf.getClass(PropertyKey.SECURITY_AUTHENTICATION_CUSTOM_PROVIDER_CLASS);
            return new CustomAuthenticationProvider(customProviderName);
          default:
            throw new AuthenticationException("Unsupported AuthType: " + authType);
        }
      }
    }
  
    /**
     * The authenticate method is called by the {@link PlainSaslServerCallbackHandler} in
     * the {@link PlainSaslServer} layer to authenticate users for their requests. If a user is to be
     * granted, return nothing/throw nothing. When a user is to be disallowed, throw an appropriate
     * {@link AuthenticationException}.
     *
     * @param user The username received over the connection request
     * @param password The password received over the connection request
     *
     * @throws AuthenticationException when a user is found to be invalid by the implementation
     */
    void authenticate(String user, String password) throws AuthenticationException;
  }
  