Source for gnu.javax.crypto.sasl.srp.ClientStore

   1: /* ClientStore.java --
   2:    Copyright (C) 2003, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2 of the License, or (at
   9: your option) any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: USA
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version.  */
  37: 
  38: 
  39: package gnu.javax.crypto.sasl.srp;
  40: 
  41: import java.util.HashMap;
  42: 
  43: /**
  44:  * The client-side implementation of the SRP security context store.
  45:  */
  46: public class ClientStore
  47: {
  48:   /** The underlying singleton. */
  49:   private static ClientStore singleton = null;
  50:   /** The map of uid --> SASL Security Context record. */
  51:   private static final HashMap uid2ssc = new HashMap();
  52:   /** The map of sid --> Session timing record. */
  53:   private static final HashMap uid2ttl = new HashMap();
  54:   /** A synchronisation lock. */
  55:   private static final Object lock = new Object();
  56: 
  57:   /** Private constructor to enforce Singleton pattern. */
  58:   private ClientStore()
  59:   {
  60:     super();
  61: 
  62:     // TODO: add a cleaning timer thread
  63:   }
  64: 
  65:   /**
  66:    * Returns the classloader Singleton.
  67:    *
  68:    * @return the classloader Singleton instance.
  69:    */
  70:   static synchronized final ClientStore instance()
  71:   {
  72:     if (singleton == null)
  73:       singleton = new ClientStore();
  74:     return singleton;
  75:   }
  76: 
  77:   /**
  78:    * Returns a boolean flag indicating if the designated client's session is
  79:    * still alive or not.
  80:    *
  81:    * @param uid the identifier of the client whose session to check.
  82:    * @return <code>true</code> if the designated client's session is still
  83:    *         alive. <code>false</code> otherwise.
  84:    */
  85:   boolean isAlive(final String uid)
  86:   {
  87:     final boolean result;
  88:     synchronized (lock)
  89:       {
  90:         final Object obj = uid2ssc.get(uid);
  91:         result = (obj != null);
  92:         if (result) // is it still alive?
  93:           {
  94:             final StoreEntry sto = (StoreEntry) uid2ttl.get(uid);
  95:             if (! sto.isAlive()) // invalidate it
  96:               {
  97:                 uid2ssc.remove(uid);
  98:                 uid2ttl.remove(uid);
  99:               }
 100:           }
 101:       }
 102:     return result;
 103:   }
 104: 
 105:   /**
 106:    * Records a mapping between a client's unique identifier and its security
 107:    * context.
 108:    *
 109:    * @param uid the unique identifier of the SRP client for which the session is
 110:    *          to be cached.
 111:    * @param ttl the session's Time-To-Live indicator (in seconds).
 112:    * @param ctx the client's security context.
 113:    */
 114:   void cacheSession(final String uid, final int ttl, final SecurityContext ctx)
 115:   {
 116:     synchronized (lock)
 117:       {
 118:         uid2ssc.put(uid, ctx);
 119:         uid2ttl.put(uid, new StoreEntry(ttl));
 120:       }
 121:   }
 122: 
 123:   /**
 124:    * Removes the mapping between the designated SRP client unique identifier and
 125:    * the its session security context (and other timing information).
 126:    *
 127:    * @param uid the identifier of the client whose session is to invalidate.
 128:    */
 129:   void invalidateSession(final String uid)
 130:   {
 131:     synchronized (lock)
 132:       {
 133:         uid2ssc.remove(uid);
 134:         uid2ttl.remove(uid);
 135:       }
 136:   }
 137: 
 138:   /**
 139:    * Returns an SRP client's security context record mapped by that client's
 140:    * unique identifier.
 141:    *
 142:    * @param uid the identifier of the client whose session is to restore.
 143:    * @return the SRP client's security context.
 144:    */
 145:   SecurityContext restoreSession(final String uid)
 146:   {
 147:     final SecurityContext result;
 148:     synchronized (lock)
 149:       {
 150:         result = (SecurityContext) uid2ssc.remove(uid);
 151:         uid2ttl.remove(uid);
 152:       }
 153:     return result;
 154:   }
 155: }