Java example source code file (CertificateFactory.java)

This example Java source code file (CertificateFactory.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

certificateexception, certificatefactory, certificatefactoryspi, certpath, collection, crl, crlexception, inputstream, instance, iterator, nosuchalgorithmexception, nosuchproviderexception, provider, security, string, util

The CertificateFactory.java Java example source code

/*
 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.security.cert;

import java.io.InputStream;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.security.Provider;
import java.security.Security;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;

import sun.security.jca.*;
import sun.security.jca.GetInstance.Instance;

/**
 * This class defines the functionality of a certificate factory, which is
 * used to generate certificate, certification path ({@code CertPath})
 * and certificate revocation list (CRL) objects from their encodings.
 *
 * <p>For encodings consisting of multiple certificates, use
 * {@code generateCertificates} when you want to
 * parse a collection of possibly unrelated certificates. Otherwise,
 * use {@code generateCertPath} when you want to generate
 * a {@code CertPath} (a certificate chain) and subsequently
 * validate it with a {@code CertPathValidator}.
 *
 * <p>A certificate factory for X.509 must return certificates that are an
 * instance of {@code java.security.cert.X509Certificate}, and CRLs
 * that are an instance of {@code java.security.cert.X509CRL}.
 *
 * <p>The following example reads a file with Base64 encoded certificates,
 * which are each bounded at the beginning by -----BEGIN CERTIFICATE-----, and
 * bounded at the end by -----END CERTIFICATE-----. We convert the
 * {@code FileInputStream} (which does not support {@code mark}
 * and {@code reset}) to a {@code BufferedInputStream} (which
 * supports those methods), so that each call to
 * {@code generateCertificate} consumes only one certificate, and the
 * read position of the input stream is positioned to the next certificate in
 * the file:
 *
 * <pre>{@code
 * FileInputStream fis = new FileInputStream(filename);
 * BufferedInputStream bis = new BufferedInputStream(fis);
 *
 * CertificateFactory cf = CertificateFactory.getInstance("X.509");
 *
 * while (bis.available() > 0) {
 *    Certificate cert = cf.generateCertificate(bis);
 *    System.out.println(cert.toString());
 * }
 * }</pre>
 *
 * <p>The following example parses a PKCS#7-formatted certificate reply stored
 * in a file and extracts all the certificates from it:
 *
 * <pre>
 * FileInputStream fis = new FileInputStream(filename);
 * CertificateFactory cf = CertificateFactory.getInstance("X.509");
 * Collection c = cf.generateCertificates(fis);
 * Iterator i = c.iterator();
 * while (i.hasNext()) {
 *    Certificate cert = (Certificate)i.next();
 *    System.out.println(cert);
 * }
 * </pre>
 *
 * <p> Every implementation of the Java platform is required to support the
 * following standard {@code CertificateFactory} type:
 * <ul>
 * <li>{@code X.509}
 * </ul>
 * and the following standard {@code CertPath} encodings:
 * <ul>
 * <li>{@code PKCS7}
 * <li>{@code PkiPath}
 * </ul>
 * The type and encodings are described in the <a href=
 * "{@docRoot}/../technotes/guides/security/StandardNames.html#CertificateFactory">
 * CertificateFactory section</a> and the  object, with the only
     * significant field being <i>certificates. In particular, the
     * signature and the contents are ignored. This format allows multiple
     * certificates to be downloaded at once. If no certificates are present,
     * an empty collection is returned.
     *
     * <p>Note that if the given input stream does not support
     * {@link java.io.InputStream#mark(int) mark} and
     * {@link java.io.InputStream#reset() reset}, this method will
     * consume the entire input stream.
     *
     * @param inStream the input stream with the certificates.
     *
     * @return a (possibly empty) collection view of
     * java.security.cert.Certificate objects
     * initialized with the data from the input stream.
     *
     * @exception CertificateException on parsing errors.
     */
    public final Collection<? extends Certificate> generateCertificates
            (InputStream inStream) throws CertificateException {
        return certFacSpi.engineGenerateCertificates(inStream);
    }

    /**
     * Generates a certificate revocation list (CRL) object and initializes it
     * with the data read from the input stream {@code inStream}.
     *
     * <p>In order to take advantage of the specialized CRL format
     * supported by this certificate factory,
     * the returned CRL object can be typecast to the corresponding
     * CRL class. For example, if this certificate
     * factory implements X.509 CRLs, the returned CRL object
     * can be typecast to the {@code X509CRL} class.
     *
     * <p>Note that if the given input stream does not support
     * {@link java.io.InputStream#mark(int) mark} and
     * {@link java.io.InputStream#reset() reset}, this method will
     * consume the entire input stream. Otherwise, each call to this
     * method consumes one CRL and the read position of the input stream
     * is positioned to the next available byte after the inherent
     * end-of-CRL marker. If the data in the
     * input stream does not contain an inherent end-of-CRL marker (other
     * than EOF) and there is trailing data after the CRL is parsed, a
     * {@code CRLException} is thrown.
     *
     * @param inStream an input stream with the CRL data.
     *
     * @return a CRL object initialized with the data
     * from the input stream.
     *
     * @exception CRLException on parsing errors.
     */
    public final CRL generateCRL(InputStream inStream)
        throws CRLException
    {
        return certFacSpi.engineGenerateCRL(inStream);
    }

    /**
     * Returns a (possibly empty) collection view of the CRLs read
     * from the given input stream {@code inStream}.
     *
     * <p>In order to take advantage of the specialized CRL format
     * supported by this certificate factory, each element in
     * the returned collection view can be typecast to the corresponding
     * CRL class. For example, if this certificate
     * factory implements X.509 CRLs, the elements in the returned
     * collection can be typecast to the {@code X509CRL} class.
     *
     * <p>In the case of a certificate factory for X.509 CRLs,
     * {@code inStream} may contain a sequence of DER-encoded CRLs.
     * In addition, {@code inStream} may contain a PKCS#7 CRL
     * set. This is a PKCS#7 <i>SignedData object, with the only
     * significant field being <i>crls. In particular, the
     * signature and the contents are ignored. This format allows multiple
     * CRLs to be downloaded at once. If no CRLs are present,
     * an empty collection is returned.
     *
     * <p>Note that if the given input stream does not support
     * {@link java.io.InputStream#mark(int) mark} and
     * {@link java.io.InputStream#reset() reset}, this method will
     * consume the entire input stream.
     *
     * @param inStream the input stream with the CRLs.
     *
     * @return a (possibly empty) collection view of
     * java.security.cert.CRL objects initialized with the data from the input
     * stream.
     *
     * @exception CRLException on parsing errors.
     */
    public final Collection<? extends CRL> generateCRLs(InputStream inStream)
            throws CRLException {
        return certFacSpi.engineGenerateCRLs(inStream);
    }
}