public class CertificateFactory
extends Object

This class defines the functionality of a certificate factory, which is used to generate certificate, certification path (CertPath) and certificate revocation list (CRL) objects from their encodings.

For encodings consisting of multiple certificates, use generateCertificates when you want to parse a collection of possibly unrelated certificates. Otherwise, use generateCertPath when you want to generate a CertPath (a certificate chain) and subsequently validate it with a CertPathValidator.

A certificate factory for X.509 must return certificates that are an instance of java.security.cert.X509Certificate, and CRLs that are an instance of java.security.cert.X509CRL.

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 FileInputStream (which does not support mark and reset) to a BufferedInputStream (which supports those methods), so that each call to generateCertificate consumes only one certificate, and the read position of the input stream is positioned to the next certificate in the file:

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());
 }

The following example parses a PKCS#7-formatted certificate reply stored in a file and extracts all the certificates from it:

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);
 }

Every implementation of the Java platform is required to support the following standard CertificateFactory type:

• X.509

and the following standard CertPath encodings:

• PKCS7
• PkiPath

The type and encodings are described in the CertificateFactory section and the CertPath Encodings section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other types or encodings are supported.

protected CertificateFactory(CertificateFactorySpi certFacSpi,
                             Provider provider,
                             String type)

public static final CertificateFactory getInstance(String type)
                                            throws CertificateException

Returns a certificate factory object that implements the specified certificate type.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new CertificateFactory object encapsulating the CertificateFactorySpi implementation from the first Provider that supports the specified type is returned.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

public static final CertificateFactory getInstance(String type,
                                                   String provider)
                                            throws CertificateException,
                                                   NoSuchProviderException

Returns a certificate factory object for the specified certificate type.

A new CertificateFactory object encapsulating the CertificateFactorySpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

public static final CertificateFactory getInstance(String type,
                                                   Provider provider)
                                            throws CertificateException

Returns a certificate factory object for the specified certificate type.

A new CertificateFactory object encapsulating the CertificateFactorySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

public final Provider getProvider()

public final String getType()

public final Certificate generateCertificate(InputStream inStream)
                                      throws CertificateException

Generates a certificate object and initializes it with the data read from the input stream inStream.

In order to take advantage of the specialized certificate format supported by this certificate factory, the returned certificate object can be typecast to the corresponding certificate class. For example, if this certificate factory implements X.509 certificates, the returned certificate object can be typecast to the X509Certificate class.

In the case of a certificate factory for X.509 certificates, the certificate provided in inStream must be DER-encoded and may be supplied in binary or printable (Base64) encoding. If the certificate is provided in Base64 encoding, it must be bounded at the beginning by -----BEGIN CERTIFICATE-----, and must be bounded at the end by -----END CERTIFICATE-----.

Note that if the given input stream does not support mark and reset, this method will consume the entire input stream. Otherwise, each call to this method consumes one certificate and the read position of the input stream is positioned to the next available byte after the inherent end-of-certificate marker. If the data in the input stream does not contain an inherent end-of-certificate marker (other than EOF) and there is trailing data after the certificate is parsed, a CertificateException is thrown.

public final Iterator<String> getCertPathEncodings()

Returns an iteration of the CertPath encodings supported by this certificate factory, with the default encoding first. See the CertPath Encodings section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard encoding names and their formats.

Attempts to modify the returned Iterator via its remove method result in an UnsupportedOperationException.

public final CertPath generateCertPath(InputStream inStream)
                                throws CertificateException

public final CertPath generateCertPath(InputStream inStream,
                                       String encoding)
                                throws CertificateException

public final CertPath generateCertPath(List<? extends Certificate> certificates)
                                throws CertificateException

Generates a CertPath object and initializes it with a List of Certificates.

The certificates supplied must be of a type supported by the CertificateFactory. They will be copied out of the supplied List object.

public final Collection<? extends Certificate> generateCertificates(InputStream inStream)
                                                             throws CertificateException

Returns a (possibly empty) collection view of the certificates read from the given input stream inStream.

In order to take advantage of the specialized certificate format supported by this certificate factory, each element in the returned collection view can be typecast to the corresponding certificate class. For example, if this certificate factory implements X.509 certificates, the elements in the returned collection can be typecast to the X509Certificate class.

In the case of a certificate factory for X.509 certificates, inStream may contain a sequence of DER-encoded certificates in the formats described for generateCertificate. In addition, inStream may contain a PKCS#7 certificate chain. This is a PKCS#7 SignedData object, with the only significant field being 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.

Note that if the given input stream does not support mark and reset, this method will consume the entire input stream.

public final CRL generateCRL(InputStream inStream)
                      throws CRLException

Generates a certificate revocation list (CRL) object and initializes it with the data read from the input stream inStream.

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 X509CRL class.

Note that if the given input stream does not support mark and 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 CRLException is thrown.

public final Collection<? extends CRL> generateCRLs(InputStream inStream)
                                             throws CRLException

Returns a (possibly empty) collection view of the CRLs read from the given input stream inStream.

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 X509CRL class.

In the case of a certificate factory for X.509 CRLs, inStream may contain a sequence of DER-encoded CRLs. In addition, inStream may contain a PKCS#7 CRL set. This is a PKCS#7 SignedData object, with the only significant field being 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.

Note that if the given input stream does not support mark and reset, this method will consume the entire input stream.