/* KeyAgreementFactory.java --
   Copyright (C) 2003, 2006 Free Software Foundation, Inc.

This file is a 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 of the License, 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.

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along with GNU Classpath; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, 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
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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
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independent module, the terms and conditions of the license of that
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package gnu.javax.crypto.key;

import gnu.java.security.Registry;

import gnu.javax.crypto.key.dh.DiffieHellmanSender;
import gnu.javax.crypto.key.dh.DiffieHellmanReceiver;
import gnu.javax.crypto.key.dh.ElGamalSender;
import gnu.javax.crypto.key.dh.ElGamalReceiver;
import gnu.javax.crypto.key.srp6.SRP6Host;
import gnu.javax.crypto.key.srp6.SRP6User;
import gnu.javax.crypto.key.srp6.SRP6SaslClient;
import gnu.javax.crypto.key.srp6.SRP6SaslServer;
import gnu.javax.crypto.key.srp6.SRP6TLSClient;
import gnu.javax.crypto.key.srp6.SRP6TLSServer;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

/**
 * A <i>Factory</i> class to generate key agreement protocol handlers.
 */
public class KeyAgreementFactory
{
  /** Trivial constructor to enforce <i>Singleton</i> pattern. */
  private KeyAgreementFactory()
  {
    super();
  }

  /**
   * Returns an instance of a key agreeent protocol handler, for party
   * <code>A</code> in a two-party <code>A..B</code> exchange, given the
   * canonical name of this protocol. Party <code>A</code> is usually the
   * initiator of the exchange.
   *
   * @param name the case-insensitive key agreement protocol name.
   * @return an instance of the key agreement protocol handler for party
   *         <code>A</code>, or <code>null</code> if none found.
   */
  public static IKeyAgreementParty getPartyAInstance(String name)
  {
    if (name == null)
      return null;
    name = name.trim();
    IKeyAgreementParty result = null;
    if (name.equalsIgnoreCase(Registry.DH_KA))
      result = new DiffieHellmanSender();
    else if (name.equalsIgnoreCase(Registry.ELGAMAL_KA))
      result = new ElGamalSender();
    else if (name.equalsIgnoreCase(Registry.SRP6_KA))
      result = new SRP6User();
    else if (name.equalsIgnoreCase(Registry.SRP_SASL_KA))
      result = new SRP6SaslClient();
    else if (name.equalsIgnoreCase(Registry.SRP_TLS_KA))
      result = new SRP6TLSClient();
    return result;
  }

  /**
   * Returns an instance of a key agreeent protocol handler, for party
   * <code>B</code> in a two-party <code>A..B</code> exchange, given the
   * canonical name of this protocol.
   *
   * @param name the case-insensitive key agreement protocol name.
   * @return an instance of the key agreement protocol handler for party
   *         <code>B</code>, or <code>null</code> if none found.
   */
  public static IKeyAgreementParty getPartyBInstance(String name)
  {
    if (name == null)
      return null;
    name = name.trim();
    IKeyAgreementParty result = null;
    if (name.equalsIgnoreCase(Registry.DH_KA))
      result = new DiffieHellmanReceiver();
    else if (name.equalsIgnoreCase(Registry.ELGAMAL_KA))
      result = new ElGamalReceiver();
    else if (name.equalsIgnoreCase(Registry.SRP6_KA))
      result = new SRP6Host();
    else if (name.equalsIgnoreCase(Registry.SRP_SASL_KA))
      result = new SRP6SaslServer();
    else if (name.equalsIgnoreCase(Registry.SRP_TLS_KA))
      result = new SRP6TLSServer();
    return result;
  }

  /**
   * Returns a {@link Set} of key agreement protocol names supported by this
   * <i>Factory</i>.
   *
   * @return a {@link Set} of key agreement protocol names (Strings).
   */
  public static final Set getNames()
  {
    HashSet hs = new HashSet();
    hs.add(Registry.DH_KA);
    hs.add(Registry.ELGAMAL_KA);
    hs.add(Registry.SRP6_KA);
    hs.add(Registry.SRP_SASL_KA);
    hs.add(Registry.SRP_TLS_KA);

    return Collections.unmodifiableSet(hs);
  }
}