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// --- BEGIN COPYRIGHT BLOCK ---
// This program 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; version 2 of the License.
//
// This program 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; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// (C) 2007 Red Hat, Inc.
// All rights reserved.
// --- END COPYRIGHT BLOCK ---
package com.netscape.certsrv.base;
import java.security.cert.X509Certificate;
import java.util.Hashtable;
import java.util.Vector;
/**
* This class manages nonces sometimes used to control request state flow.
* <P>
*
* @version $Revision$, $Date$
*/
public class Nonces {
private Hashtable<Long, X509Certificate> mNonces = new Hashtable<Long, X509Certificate>();
private Vector<Long> mNonceList = new Vector<Long>();
private int mNonceLimit;
/**
* Constructs nonces.
*/
public Nonces() {
this(100);
}
public Nonces(int limit) {
mNonceLimit = limit;
}
public long addNonce(long nonce, X509Certificate cert) {
long i;
long k = 0;
long n = nonce;
long m = (mNonceLimit / 2) + 1;
for (i = 0; i < m; i++) {
k = n + i;
// avoid collisions
if (!mNonceList.contains(k)) {
break;
}
k = n - i;
// avoid collisions
if (!mNonceList.contains(k)) {
break;
}
}
if (i < m) {
mNonceList.add(k);
mNonces.put(k, cert);
if (mNonceList.size() > mNonceLimit) {
n = mNonceList.firstElement().longValue();
mNonceList.remove(0);
mNonces.remove(n);
}
} else {
// failed to resolved collision
k = -nonce;
}
return k;
}
public X509Certificate getCertificate(long nonce) {
X509Certificate cert = mNonces.get(nonce);
return cert;
}
public X509Certificate getCertificate(int index) {
X509Certificate cert = null;
if (index >= 0 && index < mNonceList.size()) {
long nonce = mNonceList.elementAt(index).longValue();
cert = mNonces.get(nonce);
}
return cert;
}
public long getNonce(int index) {
long nonce = 0;
if (index >= 0 && index < mNonceList.size()) {
nonce = mNonceList.elementAt(index).longValue();
}
return nonce;
}
public void removeNonce(long nonce) {
mNonceList.remove(nonce);
mNonces.remove(nonce);
}
public int size() {
return mNonceList.size();
}
public int maxSize() {
return mNonceLimit;
}
public void clear() {
mNonceList.clear();
mNonces.clear();
}
public boolean isInSync() {
return (mNonceList.size() == mNonces.size());
}
}
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