/* SaslServerFactory.java
   Copyright (C) 2003, 2005, Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package javax.security.sasl;

import java.util.Map;

import javax.security.auth.callback.CallbackHandler;

/**
 * <p>An interface for creating instances of {@link SaslServer}. A class that
 * implements this interface must be thread-safe and handle multiple
 * simultaneous requests. It must also have a public constructor that accepts
 * no arguments.</p>
 *
 * <p>This interface is not normally accessed directly by a server, which will
 * use the {@link Sasl} static methods to create a {@link SaslServer} instance
 * instead. However, a particular environment may provide and install a new or
 * different <code>SaslServerFactory</code>.</p>
 *
 * @see SaslServer
 * @see Sasl
 *
 * @since 1.5
 */
public interface SaslServerFactory
{

  /**
   * Creates a {@link SaslServer} instance using the parameters supplied. It
   * returns <code>null</code> if no {@link SaslServer} instance can be created
   * using the parameters supplied. Throws {@link SaslException} if it cannot
   * create a {@link SaslServer} because of an error.
   *
   * @param mechanism the non-null IANA-registered name of a SASL mechanism
   * (e.g. "GSSAPI", "CRAM-MD5").
   * @param protocol the non-null string name of the protocol for which the
   * authentication is being performed (e.g. "ldap").
   * @param serverName the non-null fully qualified host name of the server to
   * authenticate to.
   * @param props the possibly null set of properties used to select the SASL
   * mechanism and to configure the authentication exchange of the selected
   * mechanism. See the {@link Sasl} class for a list of standard properties.
   * Other, possibly mechanism-specific, properties can be included. Properties
   * not relevant to the selected mechanism are ignored.
   * @param cbh the possibly null callback handler to used by the SASL
   * mechanisms to get further information from the application/library to
   * complete the authentication. For example, a SASL mechanism might require
   * the authentication ID, password and realm from the caller. The
   * authentication ID is requested by using a
   * {@link javax.security.auth.callback.NameCallback}. The password is
   * requested by using a {@link javax.security.auth.callback.PasswordCallback}.
   * The realm is requested by using a {@link RealmChoiceCallback} if there is
   * a list of realms to choose from, and by using a {@link RealmCallback} if
   * the realm must be entered.
   * @return a possibly null {@link SaslServer} created using the parameters
   * supplied. If <code>null</code> is returned, it means that this factory
   * cannot produce a {@link SaslServer} using the parameters supplied.
   * @throws SaslException if a SaslServer instance cannot be created because
   * of an error.
   */
  SaslServer createSaslServer(String mechanism, String protocol,
                              String serverName, Map props, CallbackHandler cbh)
    throws SaslException;

  /**
   * Returns an array of names of mechanisms that match the specified mechanism
   * selection policies.
   *
   * @param props the possibly <code>null</code> set of properties used to
   * specify the security policy of the SASL mechanisms. For example, if props
   * contains the {@link Sasl#POLICY_NOPLAINTEXT} property with the value
   * <code>"true"</code>, then the factory must not return any SASL mechanisms
   * that are susceptible to simple plain passive attacks. See the {@link Sasl}
   * class for a complete list of policy properties. Non-policy related
   * properties, if present in props, are ignored.
   * @return a non-null array containing IANA-registered SASL mechanism names.
   */
  String[] getMechanismNames(Map props);
}