CertificateFactory JDK 1.6)

Description

public class CertificateFactory

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);
 }

See also: Certificate X509Certificate CertPath CRL X509CRL

Methods

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publicfinal 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.
Returns: a certificate object initialized with the data from the input stream.
Parameters:
- inStream - an input stream with the certificate data.
Throws:
- CertificateException - on parsing errors.

publicfinal Collection<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.
Returns: a (possibly empty) collection view of java.security.cert.Certificate objects initialized with the data from the input stream.
Parameters:
- inStream - the input stream with the certificates.
Throws:
- CertificateException - on parsing errors.

publicfinal CertPath generateCertPath (InputStream inStream) throws CertificateException

Generates a CertPath object and initializes it with the data read from the InputStream inStream.

Generates a CertPath object and initializes it with
the data read from the InputStream inStream. The data
is assumed to be in the default encoding. The name of the default
encoding is the first element of the Iterator returned by
the getCertPathEncodings method.
Returns: a CertPath initialized with the data from the InputStream
Parameters:
- inStream - an InputStream containing the data
Throws:
- CertificateException - if an exception occurs while decoding
Since: 1.4

publicfinal CertPath generateCertPath (InputStream inStream, String encoding) throws CertificateException

Generates a CertPath object and initializes it with the data read from the InputStream inStream.

Generates a CertPath object and initializes it with
the data read from the InputStream inStream. The data
is assumed to be in the specified encoding. See Appendix A in the

Java Certification Path API Programmer's Guide
for information about standard encoding names and their formats.
Returns: a CertPath initialized with the data from the InputStream
Parameters:
- inStream - an InputStream containing the data
- encoding - the encoding used for the data
Throws:
- CertificateException - if an exception occurs while decoding or the encoding requested is not supported
Since: 1.4

publicfinal CertPath generateCertPath (List<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.
Returns: a CertPath initialized with the supplied list of certificates
Parameters:
- certificates - a List of Certificates
Throws:
- CertificateException - if an exception occurs
Since: 1.4

publicfinal 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 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.
Returns: a CRL object initialized with the data from the input stream.
Parameters:
- inStream - an input stream with the CRL data.
Throws:
- CRLException - on parsing errors.

publicfinal Collection<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.
Returns: a (possibly empty) collection view of java.security.cert.CRL objects initialized with the data from the input stream.
Parameters:
- inStream - the input stream with the CRLs.
Throws:
- CRLException - on parsing errors.

publicfinal Iterator<String> getCertPathEncodings ()

Returns an iteration of the CertPath encodings supported by this certificate factory, with the default encoding first.

Returns an iteration of the CertPath encodings supported by this certificate factory, with the default encoding first. See Appendix A in the Java Certification Path API Programmer's Guide for information about standard encoding names and their formats.

Attempts to modify the returned Iterator via its remove method result in an UnsupportedOperationException.
Returns: an Iterator over the names of the supported CertPath encodings (as Strings)
Since: 1.4

publicfinalstatic CertificateFactory getInstance (String type) throws CertificateException

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

publicfinalstatic CertificateFactory getInstance (String type, Provider provider) throws CertificateException

Returns a certificate factory object for the specified certificate type.

publicfinalstatic CertificateFactory getInstance (String type, String provider) throws CertificateException NoSuchProviderException

Returns a certificate factory object for the specified certificate type.

publicfinal Provider getProvider ()

Returns the provider of this certificate factory.

publicfinal String getType ()

Returns the name of the certificate type associated with this certificate factory.