http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.7. 
package org.bouncycastle.x509;

import java.security.cert.CertPath;
import java.security.cert.CertPathValidatorException;
import java.util.Collection;
import java.util.Set;

public abstract class PKIXAttrCertChecker
    implements Cloneable
{

    
Returns an immutable Set of X.509 attribute certificate
extensions that this PKIXAttrCertChecker supports or
null if no extensions are supported.


Each element of the set is a String representing the
Object Identifier (OID) of the X.509 extension that is supported.


All X.509 attribute certificate extensions that a
PKIXAttrCertChecker might possibly be able to process
should be included in the set.

Returns:an immutable Set of X.509 extension OIDs (in
        String format) supported by this
        PKIXAttrCertChecker, or null if no
        extensions are supported
/**
     * Returns an immutable <code>Set</code> of X.509 attribute certificate
     * extensions that this <code>PKIXAttrCertChecker</code> supports or
     * <code>null</code> if no extensions are supported.
     * <p>
     * Each element of the set is a <code>String</code> representing the
     * Object Identifier (OID) of the X.509 extension that is supported.
     * <p>
     * All X.509 attribute certificate extensions that a
     * <code>PKIXAttrCertChecker</code> might possibly be able to process
     * should be included in the set.
     * 
     * @return an immutable <code>Set</code> of X.509 extension OIDs (in
     *         <code>String</code> format) supported by this
     *         <code>PKIXAttrCertChecker</code>, or <code>null</code> if no
     *         extensions are supported
     */
    public abstract Set getSupportedExtensions();

    
Performs checks on the specified attribute certificate. Every handled
extension is rmeoved from the unresolvedCritExts
collection.

Params:
  • attrCert – The attribute certificate to be checked.
  • certPath – The certificate path which belongs to the attribute
           certificate issuer public key certificate.
  • holderCertPath – The certificate path which belongs to the holder
           certificate.
  • unresolvedCritExts – a Collection of OID strings
           representing the current set of unresolved critical extensions
Throws:
/**
     * Performs checks on the specified attribute certificate. Every handled
     * extension is rmeoved from the <code>unresolvedCritExts</code>
     * collection.
     * 
     * @param attrCert The attribute certificate to be checked.
     * @param certPath The certificate path which belongs to the attribute
     *            certificate issuer public key certificate.
     * @param holderCertPath The certificate path which belongs to the holder
     *            certificate.
     * @param unresolvedCritExts a <code>Collection</code> of OID strings
     *            representing the current set of unresolved critical extensions
     * @throws CertPathValidatorException if the specified attribute certificate
     *             does not pass the check.
     */
    public abstract void check(X509AttributeCertificate attrCert, CertPath certPath,
                                 CertPath holderCertPath, Collection unresolvedCritExts)
        throws CertPathValidatorException;

    
Returns a clone of this object.

Returns:a copy of this PKIXAttrCertChecker
/**
     * Returns a clone of this object.
     * 
     * @return a copy of this <code>PKIXAttrCertChecker</code>
     */
    public abstract Object clone();
}