package gnu.crypto.sasl;
// ----------------------------------------------------------------------------
// $Id: AuthInfo.java,v 1.3 2005/10/06 04:24:17 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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 Crypto 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 this program; 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.
// ----------------------------------------------------------------------------
import gnu.crypto.Registry;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.StringTokenizer;
/**
* A static class for creating {@link IAuthInfoProvider} providers. It
* transparently locates and uses any provider instances, based on the value
* assigned to the System property with the key
* <code>gnu.crypto.sasl.auth.info.provider.pkgs</code>. If more than one is
* specified they SHOULD be separated with a vertical bar character. Please note
* that the GNU provider is always added last to the list, disregarding whether
* it was mentioned or not in the value of that property, or if it that property
* was not defined.
*
* @version $Revision: 1.3 $
*/
public class AuthInfo {
// Constants and variables
// -------------------------------------------------------------------------
private static final ArrayList factories = new ArrayList();
static {
IAuthInfoProviderFactory ours = new AuthInfoProviderFactory();
// if SASL_AUTH_INFO_PROVIDER_PKGS is defined then parse it
String clazz;
String pkgs = System.getProperty(Registry.SASL_AUTH_INFO_PROVIDER_PKGS, null);
if (pkgs != null) {
for (StringTokenizer st = new StringTokenizer(pkgs, "|"); st.hasMoreTokens(); ) {
clazz = st.nextToken();
if (!"gnu.crypto.sasl".equals(clazz)) {
clazz += ".AuthInfoProviderFactory";
try {
IAuthInfoProviderFactory factory = (IAuthInfoProviderFactory)
Class.forName(clazz).newInstance();
factories.add(factory);
} catch (ClassCastException ignored) {
} catch (ClassNotFoundException ignored) {
} catch (InstantiationException ignored) {
} catch (IllegalAccessException ignored) {
}
}
}
}
// always add ours last; unless it's already there
if (!factories.contains(ours)) {
factories.add(ours);
}
}
// Constructor(s)
// -------------------------------------------------------------------------
/** Trivial constructor to enforce Singleton pattern. */
private AuthInfo() {
super();
}
// Class methods
// -------------------------------------------------------------------------
/**
* A convenience method to return the authentication information provider
* for a designated SASL mechnanism. It goes through all the installed
* provider factories, one at a time, and attempts to return a new instance
* of the provider for the designated mechanism. It stops at the first
* factory returning a non-null provider.
*
* @param mechanism the name of a SASL mechanism.
* @return an implementation that provides {@link IAuthInfoProvider} for that
* mechanism; or <code>null</code> if none found.
*/
public static IAuthInfoProvider getProvider(String mechanism) {
for (Iterator it = factories.iterator(); it.hasNext(); ) {
IAuthInfoProviderFactory factory = (IAuthInfoProviderFactory) it.next();
IAuthInfoProvider result = factory.getInstance(mechanism);
if (result != null) {
return result;
}
}
return null;
}
}