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package gnu.crypto.pad;
// ----------------------------------------------------------------------------
// $Id: PadFactory.java,v 1.6 2003/10/28 19:10:22 raif Exp $
//
// Copyright (C) 2001, 2002, 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.,
// 59 Temple Place - Suite 330,
// Boston, MA 02111-1307
// 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.Collections;
import java.util.HashSet;
import java.util.Set;
/**
* A Factory to instantiate padding schemes.
*
* @version $Revision: 1.6 $
*/
public class PadFactory implements Registry {
// Constants and variables
// -------------------------------------------------------------------------
// Constructor(s)
// -------------------------------------------------------------------------
/** Trivial constructor to enforce Singleton pattern. */
private PadFactory() {
super();
}
// Class methods
// -------------------------------------------------------------------------
/**
* Returns an instance of a padding algorithm given its name.
*
* @param pad the case-insensitive name of the padding algorithm.
* @return an instance of the padding algorithm, operating with a given
* block size, or null if none found.
* @throws InternalError if the implementation does not pass its self-test.
*/
public static final IPad getInstance(String pad) {
if (pad == null) {
return null;
}
pad = pad.trim();
IPad result = null;
if (pad.equalsIgnoreCase(PKCS7_PAD)) {
result = new PKCS7();
} else if (pad.equalsIgnoreCase(TBC_PAD)) {
result = new TBC();
} else if (pad.equalsIgnoreCase(EME_PKCS1_V1_5_PAD)) {
result = new PKCS1_V1_5();
}
if (result != null && !result.selfTest()) {
throw new InternalError(result.name());
}
return result;
}
/**
* Returns a {@link java.util.Set} of names of padding algorithms
* supported by this Factory.
*
* @return a {@link Set} of padding algorithm names (Strings).
*/
public static final Set getNames() {
HashSet hs = new HashSet();
hs.add(PKCS7_PAD);
hs.add(TBC_PAD);
hs.add(EME_PKCS1_V1_5_PAD);
return Collections.unmodifiableSet(hs);
}
// Instance methods
// -------------------------------------------------------------------------
}