| /* HMacFactory.java -- |
| Copyright (C) 2001, 2002, 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. |
| |
| You should have received a copy of the GNU General Public License |
| 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 |
| 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. */ |
| |
| |
| package gnu.javax.crypto.mac; |
| |
| import gnu.java.security.Registry; |
| import gnu.java.security.hash.HashFactory; |
| |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| /** |
| * A <i>Factory</i> to instantiate Keyed-Hash Message Authentication Code |
| * (HMAC) algorithm instances. |
| */ |
| public class HMacFactory |
| implements Registry |
| { |
| /** Trivial constructor to enforce <i>Singleton</i> pattern. */ |
| private HMacFactory() |
| { |
| super(); |
| } |
| |
| /** |
| * Return an instance of a <i>HMAC</i> algorithm given the name of its |
| * underlying hash function, prefixed with the literal defined in |
| * {@link Registry#HMAC_NAME_PREFIX}. |
| * |
| * @param name the fully qualified name of the underlying algorithm: composed |
| * as the concatenation of a literal prefix (see |
| * {@link Registry#HMAC_NAME_PREFIX}) and the name of the underlying |
| * hash algorithm. |
| * @return an instance of the <i>HMAC</i> algorithm, or <code>null</code> |
| * if none can be constructed. |
| * @exception InternalError if the implementation does not pass its self-test. |
| */ |
| public static IMac getInstance(String name) |
| { |
| if (name == null) |
| return null; |
| |
| name = name.trim(); |
| name = name.toLowerCase(); |
| if (! name.startsWith(HMAC_NAME_PREFIX)) |
| return null; |
| |
| // strip the prefix |
| name = name.substring(HMAC_NAME_PREFIX.length()).trim(); |
| IMac result = new HMac(HashFactory.getInstance(name)); |
| if (result != null && ! result.selfTest()) |
| throw new InternalError(result.name()); |
| |
| return result; |
| } |
| |
| /** |
| * <p> |
| * Returns a {@link java.util.Set} of names of <i>HMAC</i> algorithms |
| * supported by this <i>Factory</i>. |
| * </p> |
| * |
| * @return a {@link java.util.Set} of HMAC algorithm names (Strings). |
| */ |
| public static final Set getNames() |
| { |
| Set hashNames = HashFactory.getNames(); |
| HashSet hs = new HashSet(); |
| for (Iterator it = hashNames.iterator(); it.hasNext();) |
| hs.add(HMAC_NAME_PREFIX + ((String) it.next())); |
| |
| return Collections.unmodifiableSet(hs); |
| } |
| } |