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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package javax.security.sasl;

import java.util.Map;
import javax.security.auth.callback.CallbackHandler;

/**
 * An interface for creating instances of {@code 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
 * argument.
 *<p>
 * This interface is not normally accessed directly by a server, which will use the
 * {@code Sasl} static methods
 * instead. However, a particular environment may provide and install a
 * new or different {@code SaslServerFactory}.
 *
 * @since 1.5
 *
 * @see SaslServer
 * @see Sasl
 *
 * @author Rosanna Lee
 * @author Rob Weltman
 */
public abstract interface SaslServerFactory {
    /**
     * Creates a {@code SaslServer} using the parameters supplied.
     * It returns null
     * if no {@code SaslServer} can be created using the parameters supplied.
     * Throws {@code SaslException} if it cannot create a {@code 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 fully qualified host name of the server to
     * authenticate to, or null if the server is not bound to any specific host
     * name. If the mechanism does not allow an unbound server, a
     * {@code SaslException} will be thrown.
     * @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 {@code 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,
     * including any map entries with non-String keys.
     *
     * @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 {@code NameCallback}.
     * The password is requested by using a {@code PasswordCallback}.
     * The realm is requested by using a {@code RealmChoiceCallback} if there is a list
     * of realms to choose from, and by using a {@code RealmCallback} if
     * the realm must be entered.
     *
     *@return A possibly null {@code SaslServer} created using the parameters
     * supplied. If null, this factory cannot produce a {@code SaslServer}
     * using the parameters supplied.
     *@exception SaslException If cannot create a {@code SaslServer} because
     * of an error.
     */
    public abstract SaslServer createSaslServer(
        String mechanism,
        String protocol,
        String serverName,
        Map<String,?> props,
        CallbackHandler cbh) throws SaslException;

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