001    /* PKIXCertPathChecker.java -- checks X.509 certificate paths.
002       Copyright (C) 2003 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.security.cert;
040    
041    import java.util.Collection;
042    import java.util.Set;
043    
044    /**
045     * A validator for X.509 certificates when approving certificate chains.
046     *
047     * <p>Concrete subclasses can be passed to the {@link
048     * PKIXParameters#setCertPathCheckers(java.util.List)} and {@link
049     * PKIXParameters#addCertPathChecker(java.security.cert.PKIXCertPathChecker)}
050     * methods, which are then used to set up PKIX certificate chain
051     * builders or validators. These classes then call the {@link
052     * #check(java.security.cert.Certificate,java.util.Collection)} method
053     * of this class, performing whatever checks on the certificate,
054     * throwing an exception if any check fails.
055     *
056     * <p>Subclasses of this must be able to perform their checks in the
057     * backward direction -- from the most-trusted certificate to the target
058     * -- and may optionally support forward checking -- from the target to
059     * the most-trusted certificate.
060     *
061     * @see PKIXParameters
062     * @since 1.4
063     */
064    public abstract class PKIXCertPathChecker implements Cloneable
065    {
066    
067      // Constructor.
068      // ------------------------------------------------------------------------
069    
070      /** Default constructor. */
071      protected PKIXCertPathChecker()
072      {
073        super();
074      }
075    
076      // Cloneable interface.
077      // ------------------------------------------------------------------------
078    
079      public Object clone()
080      {
081        try
082          {
083            return super.clone();
084          }
085        catch (CloneNotSupportedException cnse)
086          {
087            throw new InternalError(cnse.getMessage());
088          }
089      }
090    
091      // Abstract methods.
092      // ------------------------------------------------------------------------
093    
094      /**
095       * Initialize this PKIXCertPathChecker. If subclasses support forward
096       * checking, a value of true can be passed to this method, and
097       * certificates can be validated from the target certificate to the
098       * most-trusted certifcate.
099       *
100       * @param forward The direction of this PKIXCertPathChecker.
101       * @throws CertPathValidatorException If <i>forward</i> is true and
102       *         this class does not support forward checking.
103       */
104      public abstract void init(boolean forward) throws CertPathValidatorException;
105    
106      /**
107       * Returns whether or not this class supports forward checking.
108       *
109       * @return Whether or not this class supports forward checking.
110       */
111      public abstract boolean isForwardCheckingSupported();
112    
113      /**
114       * Returns an immutable set of X.509 extension object identifiers (OIDs)
115       * supported by this PKIXCertPathChecker.
116       *
117       * @return An immutable set of Strings of the supported X.509 OIDs, or
118       *         null if no extensions are supported.
119       */
120      public abstract Set<String> getSupportedExtensions();
121    
122      /**
123       * Checks a certificate, removing any critical extensions that are
124       * resolved in this check.
125       *
126       * @param cert               The certificate to check.
127       * @param unresolvedCritExts The (mutable) collection of as-of-yet
128       *        unresolved critical extensions, as OID strings.
129       * @throws CertPathValidatorException If this certificate fails this
130       *         check.
131       */
132      public abstract void check(Certificate cert, Collection<String> unresolvedCritExts)
133      throws CertPathValidatorException;
134    }