/**
 * EasyBeans
 * Copyright (C) 2010 Bull S.A.S.
 * Contact: easybeans@objectweb.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 * --------------------------------------------------------------------------
 * $Id: AuthConfigProvider.java 6201 2012-03-21 10:28:10Z benoitf $
 * --------------------------------------------------------------------------
 */
package javax.security.auth.message.config;

import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.message.AuthException;

/**
 * This interface is implemented by objects that can be used to obtain
 * authentication context configuration objects, that is,
 * <code>ClientAuthConfig</code> or <code>ServerAuthConfig</code> objects.
 *
 * <p />
 *
 * Authentication context configuration objects serve as sources of
 * the authentication context objects, that is, <code>ClientAuthContext</code> or
 * <code>ServerAuthContext</code> objects, for a specific message layer
 * and messaging context.
 *
 * <p />
 *
 * Authentication context objects encapsulate the initialization,
 * configuration, and invocation of authentication modules, that is,
 * <code>ClientAuthModule</code> or <code>ServerAuthModule</code> objects, for
 * a specific message exchange within a specific message layer and
 * messaging context.
 *
 * <p />
 *
 * Callers do not directly operate on authentication modules.
 * Instead, they rely on a ClientAuthContext or ServerAuthContext
 * to manage the invocation of modules. A caller obtains an instance
 * of ClientAuthContext or ServerAuthContext by calling the respective
 * <code>getAuthContext</code> method on a <code>ClientAuthConfig</code>
 * or <code>ServerAuthConfig</code> object obtained from an
 * AuthConfigProvider.
 *
 * <p />
 *
 * The following represents a typical sequence of calls for obtaining
 * a client authentication context object, and then using it to secure
 * a request.
 * <ol>
 * <li>AuthConfigProvider provider;</li>
 * <li>ClientAuthConfig config = provider.getClientAuthConfig(layer,appID,cbh);</li>
 * <li>String authContextID = config.getAuthContextID(messageInfo);</li>
 * <li>ClientAuthContext context = config.getAuthContext(authContextID,subject,properties);</li>
 * <li>context.secureRequest(messageInfo,subject);</li>
 * </ol>
 *
* <p />
 *
 * Every implementation of this interface must offer a public,
 * two argument constructor with the following signature:
 * <pre>
 * <code>
 * public AuthConfigProviderImpl(Map properties, AuthConfigFactory factory);
 * </code>
 * </pre>
 * where the properties argument may be null, and where all values and
 * keys occurring in a non-null properties argument must be of type String.
 * When the factory argument is not null, it indicates that the
 * provider is to self-register at the factory by calling the following
 * method on the factory:
 * <pre>
 * <code>
 * public String
 * registerConfigProvider(AuthConfigProvider provider, String layer,
 *                        String appContext, String description);
 * </code>
 * </pre>
 * @version 1.0
 *
 * @see ClientAuthContext
 * @see ServerAuthContext
 * @see AuthConfigFactory
 */
public interface AuthConfigProvider {

    /**
     * Get an instance of ClientAuthConfig from this provider.
     *
     * <p />
     *
     * The implementation of this method returns a ClientAuthConfig
     * instance that describes the configuration of ClientAuthModules
     * at a given message layer, and for use in an identified application
     * context.
     *
     * @param layer A String identifying the message layer
     *		for the returned ClientAuthConfig object.
     *          This argument must not be null.
     *
     * @param appContext A String that identifies the messaging context
     *          for the returned ClientAuthConfig object.
     *          This argument must not be null.
     *
     * @param handler A CallbackHandler to be passed to the ClientAuthModules
     *		encapsulated by ClientAuthContext objects derived from the
     *		returned ClientAuthConfig. This argument may be null,
     *		in which case the implementation may assign a default handler
     *		to the configuration.
     *          The CallbackHandler assigned to the configuration must support
     *          the Callback objects required to be supported by the profile
     *          of this specification being followed by the messaging runtime.
     *          The CallbackHandler instance must be initialized with any
     *          application context needed to process the required callbacks
     *          on behalf of the corresponding application.
     *
     * @return A ClientAuthConfig Object that describes the configuration
     *		of ClientAuthModules at the message layer and messaging context
     *          identified by the layer and appContext arguments.
     *		This method does not return null.
     *
     * @exception AuthException If this provider does not support the
     *          assignment of a default CallbackHandler to the returned
     *          ClientAuthConfig.
     *
     * @exception SecurityException If the caller does not have permission
     *		to retrieve the configuration.
     */
    public ClientAuthConfig getClientAuthConfig (String layer,
            String appContext, CallbackHandler handler) throws AuthException;

    /**
     * Get an instance of ServerAuthConfig from this provider.
     *
     * <p />
     *
     * The implementation of this method returns a ServerAuthConfig
     * instance that describes the configuration of ServerAuthModules
     * at a given message layer, and for a particular application context.
     *
     * @param layer A String identifying the message layer
     *		for the returned ServerAuthConfig object.
     *          This argument must not be null.
     *
     * @param appContext A String that identifies the messaging context
     *          for the returned ServerAuthConfig object.
     *          This argument must not be null.
     *
     * @param handler A CallbackHandler to be passed to the ServerAuthModules
     *		encapsulated by ServerAuthContext objects derived from the
     *		returned ServerAuthConfig. This argument may be null,
     *		in which case the implementation may assign a default handler
     *		to the configuration.
     *          The CallbackHandler assigned to the configuration must support
     *          the Callback objects required to be supported by the profile
     *          of this specification being followed by the messaging runtime.
     *          The CallbackHandler instance must be initialized with any
     *          application context needed to process the required callbacks
     *          on behalf of the corresponding application.
     *
     * @return A ServerAuthConfig Object that describes the configuration
     *		of ServerAuthModules at a given message layer,
     *		and for a particular application context.
     *          This method does not return null.
     *
     * @exception AuthException If this provider does not support the
     *          assignment of a default CallbackHandler to the returned
     *          ServerAuthConfig.
     *
     * @exception SecurityException If the caller does not have permission
     *		to retrieve the configuration.
     */
    public ServerAuthConfig getServerAuthConfig (String layer,
            String appContext, CallbackHandler handler) throws AuthException;

   /**
     * Causes a dynamic configuration provider to update its internal
     * state such that any resulting change to its state is reflected in
     * the corresponding authentication context configuration objects
     * previously created by the provider within the current process context.
     *
     * @exception AuthException If an error occurred during the refresh.
     *
     * @exception SecurityException If the caller does not have permission
     *		to refresh the provider.
     */
    public void refresh();

}
