https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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package sun.security.x509;

import java.lang.reflect.*;
import java.io.IOException;
import java.security.PrivilegedExceptionAction;
import java.security.AccessController;
import java.security.Principal;
import java.util.*;

import sun.security.util.*;
import javax.security.auth.x500.X500Principal;


Note:  As of 1.4, the public class,
javax.security.auth.x500.X500Principal,
should be used when parsing, generating, and comparing X.500 DNs.
This class contains other useful methods for checking name constraints
and retrieving DNs by keyword.

 X.500 names are used to identify entities, such as those which are
identified by X.509 certificates.  They are world-wide, hierarchical,
and descriptive.  Entities can be identified by attributes, and in
some systems can be searched for according to those attributes.


The ASN.1 for this is:

GeneralName ::= CHOICE {
....
    directoryName                   [4]     Name,
....
Name ::= CHOICE {
  RDNSequence }
RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
RelativeDistinguishedName ::=
  SET OF AttributeTypeAndValue
AttributeTypeAndValue ::= SEQUENCE {
  type     AttributeType,
  value    AttributeValue }
AttributeType ::= OBJECT IDENTIFIER
AttributeValue ::= ANY DEFINED BY AttributeType
....
DirectoryString ::= CHOICE {
      teletexString           TeletexString (SIZE (1..MAX)),
      printableString         PrintableString (SIZE (1..MAX)),
      universalString         UniversalString (SIZE (1..MAX)),
      utf8String              UTF8String (SIZE (1.. MAX)),
      bmpString               BMPString (SIZE (1..MAX)) }




This specification requires only a subset of the name comparison
functionality specified in the X.500 series of specifications.  The
requirements for conforming implementations are as follows:

    

  1. attribute values encoded in different types (e.g.,
   PrintableString and BMPString) may be assumed to represent
   different strings;

    

  2. attribute values in types other than PrintableString are case
   sensitive (this permits matching of attribute values as binary
   objects);

    

  3. attribute values in PrintableString are not case sensitive
   (e.g., "Marianne Swanson" is the same as "MARIANNE SWANSON"); and

    

  4. attribute values in PrintableString are compared after
   removing leading and trailing white space and converting internal
   substrings of one or more consecutive white space characters to a
   single space.




These name comparison rules permit a certificate user to validate
certificates issued using languages or encodings unfamiliar to the
certificate user.


In addition, implementations of this specification MAY use these
comparison rules to process unfamiliar attribute types for name
chaining. This allows implementations to process certificates with
unfamiliar attributes in the issuer name.


Note that the comparison rules defined in the X.500 series of
specifications indicate that the character sets used to encode data
in distinguished names are irrelevant.  The characters themselves are
compared without regard to encoding. Implementations of the profile
are permitted to use the comparison algorithm defined in the X.500
series.  Such an implementation will recognize a superset of name
matches recognized by the algorithm specified above.


Note that instances of this class are immutable.

Author:David Brownell, Amit Kapoor, Hemma Prafullchandra
See Also:
/**
 * Note:  As of 1.4, the public class,
 * javax.security.auth.x500.X500Principal,
 * should be used when parsing, generating, and comparing X.500 DNs.
 * This class contains other useful methods for checking name constraints
 * and retrieving DNs by keyword.
 *
 * <p> X.500 names are used to identify entities, such as those which are
 * identified by X.509 certificates.  They are world-wide, hierarchical,
 * and descriptive.  Entities can be identified by attributes, and in
 * some systems can be searched for according to those attributes.
 * <p>
 * The ASN.1 for this is:
 * <pre>
 * GeneralName ::= CHOICE {
 * ....
 *     directoryName                   [4]     Name,
 * ....
 * Name ::= CHOICE {
 *   RDNSequence }
 *
 * RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
 *
 * RelativeDistinguishedName ::=
 *   SET OF AttributeTypeAndValue
 *
 * AttributeTypeAndValue ::= SEQUENCE {
 *   type     AttributeType,
 *   value    AttributeValue }
 *
 * AttributeType ::= OBJECT IDENTIFIER
 *
 * AttributeValue ::= ANY DEFINED BY AttributeType
 * ....
 * DirectoryString ::= CHOICE {
 *       teletexString           TeletexString (SIZE (1..MAX)),
 *       printableString         PrintableString (SIZE (1..MAX)),
 *       universalString         UniversalString (SIZE (1..MAX)),
 *       utf8String              UTF8String (SIZE (1.. MAX)),
 *       bmpString               BMPString (SIZE (1..MAX)) }
 * </pre>
 * <p>
 * This specification requires only a subset of the name comparison
 * functionality specified in the X.500 series of specifications.  The
 * requirements for conforming implementations are as follows:
 * <ol TYPE=a>
 * <li>attribute values encoded in different types (e.g.,
 *    PrintableString and BMPString) may be assumed to represent
 *    different strings;
 * <p>
 * <li>attribute values in types other than PrintableString are case
 *    sensitive (this permits matching of attribute values as binary
 *    objects);
 * <p>
 * <li>attribute values in PrintableString are not case sensitive
 *    (e.g., "Marianne Swanson" is the same as "MARIANNE SWANSON"); and
 * <p>
 * <li>attribute values in PrintableString are compared after
 *    removing leading and trailing white space and converting internal
 *    substrings of one or more consecutive white space characters to a
 *    single space.
 * </ol>
 * <p>
 * These name comparison rules permit a certificate user to validate
 * certificates issued using languages or encodings unfamiliar to the
 * certificate user.
 * <p>
 * In addition, implementations of this specification MAY use these
 * comparison rules to process unfamiliar attribute types for name
 * chaining. This allows implementations to process certificates with
 * unfamiliar attributes in the issuer name.
 * <p>
 * Note that the comparison rules defined in the X.500 series of
 * specifications indicate that the character sets used to encode data
 * in distinguished names are irrelevant.  The characters themselves are
 * compared without regard to encoding. Implementations of the profile
 * are permitted to use the comparison algorithm defined in the X.500
 * series.  Such an implementation will recognize a superset of name
 * matches recognized by the algorithm specified above.
 * <p>
 * Note that instances of this class are immutable.
 *
 * @author David Brownell
 * @author Amit Kapoor
 * @author Hemma Prafullchandra
 * @see GeneralName
 * @see GeneralNames
 * @see GeneralNameInterface
 */

public class X500Name implements GeneralNameInterface, Principal {

    private String dn; // roughly RFC 1779 DN, or null
    private String rfc1779Dn; // RFC 1779 compliant DN, or null
    private String rfc2253Dn; // RFC 2253 DN, or null
    private String canonicalDn; // canonical RFC 2253 DN or null
    private RDN[] names;        // RDNs (never null)
    private X500Principal x500Principal;
    private byte[] encoded;

    // cached immutable list of the RDNs and all the AVAs
    private volatile List<RDN> rdnList;
    private volatile List<AVA> allAvaList;

    
Constructs a name from a conventionally formatted string, such
as "CN=Dave, OU=JavaSoft, O=Sun Microsystems, C=US".
(RFC 1779, 2253, or 4514 style).

Params:
  • dname – the X.500 Distinguished Name
/**
     * Constructs a name from a conventionally formatted string, such
     * as "CN=Dave, OU=JavaSoft, O=Sun Microsystems, C=US".
     * (RFC 1779, 2253, or 4514 style).
     *
     * @param dname the X.500 Distinguished Name
     */
    public X500Name(String dname) throws IOException {
        this(dname, Collections.<String, String>emptyMap());
    }

    
Constructs a name from a conventionally formatted string, such
as "CN=Dave, OU=JavaSoft, O=Sun Microsystems, C=US".
(RFC 1779, 2253, or 4514 style).

Params:
  • dname – the X.500 Distinguished Name
  • keywordMap – an additional keyword/OID map
/**
     * Constructs a name from a conventionally formatted string, such
     * as "CN=Dave, OU=JavaSoft, O=Sun Microsystems, C=US".
     * (RFC 1779, 2253, or 4514 style).
     *
     * @param dname the X.500 Distinguished Name
     * @param keywordMap an additional keyword/OID map
     */
    public X500Name(String dname, Map<String, String> keywordMap)
        throws IOException {
        parseDN(dname, keywordMap);
    }

    
Constructs a name from a string formatted according to format.
Currently, the formats DEFAULT and RFC2253 are supported.
DEFAULT is the default format used by the X500Name(String)
constructor. RFC2253 is the format strictly according to RFC2253
without extensions.

Params:
  • dname – the X.500 Distinguished Name
  • format – the specified format of the String DN
/**
     * Constructs a name from a string formatted according to format.
     * Currently, the formats DEFAULT and RFC2253 are supported.
     * DEFAULT is the default format used by the X500Name(String)
     * constructor. RFC2253 is the format strictly according to RFC2253
     * without extensions.
     *
     * @param dname the X.500 Distinguished Name
     * @param format the specified format of the String DN
     */
    public X500Name(String dname, String format) throws IOException {
        if (dname == null) {
            throw new NullPointerException("Name must not be null");
        }
        if (format.equalsIgnoreCase("RFC2253")) {
            parseRFC2253DN(dname);
        } else if (format.equalsIgnoreCase("DEFAULT")) {
            parseDN(dname, Collections.<String, String>emptyMap());
        } else {
            throw new IOException("Unsupported format " + format);
        }
    }

    
Constructs a name from fields common in enterprise application
environments.

NOTE:  The behaviour when any of
these strings contain characters outside the ASCII range
is unspecified in currently relevant standards.

Params:
  • commonName – common name of a person, e.g. "Vivette Davis"
  • organizationUnit – small organization name, e.g. "Purchasing"
  • organizationName – large organization name, e.g. "Onizuka, Inc."
  • country – two letter country code, e.g. "CH"
/**
     * Constructs a name from fields common in enterprise application
     * environments.
     *
     * <P><EM><STRONG>NOTE:</STRONG>  The behaviour when any of
     * these strings contain characters outside the ASCII range
     * is unspecified in currently relevant standards.</EM>
     *
     * @param commonName common name of a person, e.g. "Vivette Davis"
     * @param organizationUnit small organization name, e.g. "Purchasing"
     * @param organizationName large organization name, e.g. "Onizuka, Inc."
     * @param country two letter country code, e.g. "CH"
     */
    public X500Name(String commonName, String organizationUnit,
                     String organizationName, String country)
    throws IOException {
        names = new RDN[4];
        /*
         * NOTE:  it's only on output that little-endian
         * ordering is used.
         */
        names[3] = new RDN(1);
        names[3].assertion[0] = new AVA(commonName_oid,
                new DerValue(commonName));
        names[2] = new RDN(1);
        names[2].assertion[0] = new AVA(orgUnitName_oid,
                new DerValue(organizationUnit));
        names[1] = new RDN(1);
        names[1].assertion[0] = new AVA(orgName_oid,
                new DerValue(organizationName));
        names[0] = new RDN(1);
        names[0].assertion[0] = new AVA(countryName_oid,
                new DerValue(country));
    }

    
Constructs a name from fields common in Internet application
environments.

NOTE:  The behaviour when any of
these strings contain characters outside the ASCII range
is unspecified in currently relevant standards.

Params:
  • commonName – common name of a person, e.g. "Vivette Davis"
  • organizationUnit – small organization name, e.g. "Purchasing"
  • organizationName – large organization name, e.g. "Onizuka, Inc."
  • localityName – locality (city) name, e.g. "Palo Alto"
  • stateName – state name, e.g. "California"
  • country – two letter country code, e.g. "CH"
/**
     * Constructs a name from fields common in Internet application
     * environments.
     *
     * <P><EM><STRONG>NOTE:</STRONG>  The behaviour when any of
     * these strings contain characters outside the ASCII range
     * is unspecified in currently relevant standards.</EM>
     *
     * @param commonName common name of a person, e.g. "Vivette Davis"
     * @param organizationUnit small organization name, e.g. "Purchasing"
     * @param organizationName large organization name, e.g. "Onizuka, Inc."
     * @param localityName locality (city) name, e.g. "Palo Alto"
     * @param stateName state name, e.g. "California"
     * @param country two letter country code, e.g. "CH"
     */
    public X500Name(String commonName, String organizationUnit,
                    String organizationName, String localityName,
                    String stateName, String country)
    throws IOException {
        names = new RDN[6];
        /*
         * NOTE:  it's only on output that little-endian
         * ordering is used.
         */
        names[5] = new RDN(1);
        names[5].assertion[0] = new AVA(commonName_oid,
                new DerValue(commonName));
        names[4] = new RDN(1);
        names[4].assertion[0] = new AVA(orgUnitName_oid,
                new DerValue(organizationUnit));
        names[3] = new RDN(1);
        names[3].assertion[0] = new AVA(orgName_oid,
                new DerValue(organizationName));
        names[2] = new RDN(1);
        names[2].assertion[0] = new AVA(localityName_oid,
                new DerValue(localityName));
        names[1] = new RDN(1);
        names[1].assertion[0] = new AVA(stateName_oid,
                new DerValue(stateName));
        names[0] = new RDN(1);
        names[0].assertion[0] = new AVA(countryName_oid,
                new DerValue(country));
    }

    
Constructs a name from an array of relative distinguished names

Params:
  • rdnArray – array of relative distinguished names
Throws:
/**
     * Constructs a name from an array of relative distinguished names
     *
     * @param rdnArray array of relative distinguished names
     * @throws IOException on error
     */
    public X500Name(RDN[] rdnArray) throws IOException {
        if (rdnArray == null) {
            names = new RDN[0];
        } else {
            names = rdnArray.clone();
            for (int i = 0; i < names.length; i++) {
                if (names[i] == null) {
                    throw new IOException("Cannot create an X500Name");
                }
            }
        }
    }

    
Constructs a name from an ASN.1 encoded value.  The encoding
of the name in the stream uses DER (a BER/1 subset).

Params:
  • value – a DER-encoded value holding an X.500 name.
/**
     * Constructs a name from an ASN.1 encoded value.  The encoding
     * of the name in the stream uses DER (a BER/1 subset).
     *
     * @param value a DER-encoded value holding an X.500 name.
     */
    public X500Name(DerValue value) throws IOException {
        //Note that toDerInputStream uses only the buffer (data) and not
        //the tag, so an empty SEQUENCE (OF) will yield an empty DerInputStream
        this(value.toDerInputStream());
    }

    
Constructs a name from an ASN.1 encoded input stream.  The encoding
of the name in the stream uses DER (a BER/1 subset).

Params:
  • in – DER-encoded data holding an X.500 name.
/**
     * Constructs a name from an ASN.1 encoded input stream.  The encoding
     * of the name in the stream uses DER (a BER/1 subset).
     *
     * @param in DER-encoded data holding an X.500 name.
     */
    public X500Name(DerInputStream in) throws IOException {
        parseDER(in);
    }

    
 Constructs a name from an ASN.1 encoded byte array.

Params:
  • name – DER-encoded byte array holding an X.500 name.
/**
     *  Constructs a name from an ASN.1 encoded byte array.
     *
     * @param name DER-encoded byte array holding an X.500 name.
     */
    public X500Name(byte[] name) throws IOException {
        DerInputStream in = new DerInputStream(name);
        parseDER(in);
    }

    
Return an immutable List of all RDNs in this X500Name.

/**
     * Return an immutable List of all RDNs in this X500Name.
     */
    public List<RDN> rdns() {
        List<RDN> list = rdnList;
        if (list == null) {
            list = Collections.unmodifiableList(Arrays.asList(names));
            rdnList = list;
        }
        return list;
    }

    
Return the number of RDNs in this X500Name.

/**
     * Return the number of RDNs in this X500Name.
     */
    public int size() {
        return names.length;
    }

    
Return an immutable List of the the AVAs contained in all the
RDNs of this X500Name.

/**
     * Return an immutable List of the the AVAs contained in all the
     * RDNs of this X500Name.
     */
    public List<AVA> allAvas() {
        List<AVA> list = allAvaList;
        if (list == null) {
            list = new ArrayList<AVA>();
            for (int i = 0; i < names.length; i++) {
                list.addAll(names[i].avas());
            }
            list = Collections.unmodifiableList(list);
            allAvaList = list;
        }
        return list;
    }

    
Return the total number of AVAs contained in all the RDNs of
this X500Name.

/**
     * Return the total number of AVAs contained in all the RDNs of
     * this X500Name.
     */
    public int avaSize() {
        return allAvas().size();
    }

    
Return whether this X500Name is empty. An X500Name is not empty
if it has at least one RDN containing at least one AVA.

/**
     * Return whether this X500Name is empty. An X500Name is not empty
     * if it has at least one RDN containing at least one AVA.
     */
    public boolean isEmpty() {
        int n = names.length;
        for (int i = 0; i < n; i++) {
            if (names[i].assertion.length != 0) {
                return false;
            }
        }
        return true;
    }

    
Calculates a hash code value for the object.  Objects
which are equal will also have the same hashcode.

/**
     * Calculates a hash code value for the object.  Objects
     * which are equal will also have the same hashcode.
     */
    public int hashCode() {
        return getRFC2253CanonicalName().hashCode();
    }

    
Compares this name with another, for equality.

Returns:true iff the names are identical.
/**
     * Compares this name with another, for equality.
     *
     * @return true iff the names are identical.
     */
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof X500Name == false) {
            return false;
        }
        X500Name other = (X500Name)obj;
        // if we already have the canonical forms, compare now
        if ((this.canonicalDn != null) && (other.canonicalDn != null)) {
            return this.canonicalDn.equals(other.canonicalDn);
        }
        // quick check that number of RDNs and AVAs match before canonicalizing
        int n = this.names.length;
        if (n != other.names.length) {
            return false;
        }
        for (int i = 0; i < n; i++) {
            RDN r1 = this.names[i];
            RDN r2 = other.names[i];
            if (r1.assertion.length != r2.assertion.length) {
                return false;
            }
        }
        // definite check via canonical form
        String thisCanonical = this.getRFC2253CanonicalName();
        String otherCanonical = other.getRFC2253CanonicalName();
        return thisCanonical.equals(otherCanonical);
    }

    /*
     * Returns the name component as a Java string, regardless of its
     * encoding restrictions.
     */
    private String getString(DerValue attribute) throws IOException {
        if (attribute == null)
            return null;
        String  value = attribute.getAsString();

        if (value == null)
            throw new IOException("not a DER string encoding, "
                    + attribute.tag);
        else
            return value;
    }

    
Return type of GeneralName.

/**
     * Return type of GeneralName.
     */
    public int getType() {
        return (GeneralNameInterface.NAME_DIRECTORY);
    }

    
Returns a "Country" name component.  If more than one
such attribute exists, the topmost one is returned.

Returns:"C=" component of the name, if any.
/**
     * Returns a "Country" name component.  If more than one
     * such attribute exists, the topmost one is returned.
     *
     * @return "C=" component of the name, if any.
     */
    public String getCountry() throws IOException {
        DerValue attr = findAttribute(countryName_oid);

        return getString(attr);
    }


    
Returns an "Organization" name component.  If more than
one such attribute exists, the topmost one is returned.

Returns:"O=" component of the name, if any.
/**
     * Returns an "Organization" name component.  If more than
     * one such attribute exists, the topmost one is returned.
     *
     * @return "O=" component of the name, if any.
     */
    public String getOrganization() throws IOException {
        DerValue attr = findAttribute(orgName_oid);

        return getString(attr);
    }


    
Returns an "Organizational Unit" name component.  If more
than one such attribute exists, the topmost one is returned.

Returns:"OU=" component of the name, if any.
/**
     * Returns an "Organizational Unit" name component.  If more
     * than one such attribute exists, the topmost one is returned.
     *
     * @return "OU=" component of the name, if any.
     */
    public String getOrganizationalUnit() throws IOException {
        DerValue attr = findAttribute(orgUnitName_oid);

        return getString(attr);
    }


    
Returns a "Common Name" component.  If more than one such
attribute exists, the topmost one is returned.

Returns:"CN=" component of the name, if any.
/**
     * Returns a "Common Name" component.  If more than one such
     * attribute exists, the topmost one is returned.
     *
     * @return "CN=" component of the name, if any.
     */
    public String getCommonName() throws IOException {
        DerValue attr = findAttribute(commonName_oid);

        return getString(attr);
    }


    
Returns a "Locality" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"L=" component of the name, if any.
/**
     * Returns a "Locality" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "L=" component of the name, if any.
     */
    public String getLocality() throws IOException {
        DerValue attr = findAttribute(localityName_oid);

        return getString(attr);
    }

    
Returns a "State" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"S=" component of the name, if any.
/**
     * Returns a "State" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "S=" component of the name, if any.
     */
    public String getState() throws IOException {
      DerValue attr = findAttribute(stateName_oid);

        return getString(attr);
    }

    
Returns a "Domain" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"DC=" component of the name, if any.
/**
     * Returns a "Domain" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "DC=" component of the name, if any.
     */
    public String getDomain() throws IOException {
        DerValue attr = findAttribute(DOMAIN_COMPONENT_OID);

        return getString(attr);
    }

    
Returns a "DN Qualifier" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"DNQ=" component of the name, if any.
/**
     * Returns a "DN Qualifier" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "DNQ=" component of the name, if any.
     */
    public String getDNQualifier() throws IOException {
        DerValue attr = findAttribute(DNQUALIFIER_OID);

        return getString(attr);
    }

    
Returns a "Surname" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"SURNAME=" component of the name, if any.
/**
     * Returns a "Surname" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "SURNAME=" component of the name, if any.
     */
    public String getSurname() throws IOException {
        DerValue attr = findAttribute(SURNAME_OID);

        return getString(attr);
    }

    
Returns a "Given Name" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"GIVENNAME=" component of the name, if any.
/**
     * Returns a "Given Name" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "GIVENNAME=" component of the name, if any.
     */
    public String getGivenName() throws IOException {
       DerValue attr = findAttribute(GIVENNAME_OID);

       return getString(attr);
    }

    
Returns an "Initials" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"INITIALS=" component of the name, if any.
/**
     * Returns an "Initials" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "INITIALS=" component of the name, if any.
     */
    public String getInitials() throws IOException {
        DerValue attr = findAttribute(INITIALS_OID);

        return getString(attr);
     }

     
Returns a "Generation Qualifier" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"GENERATION=" component of the name, if any.
/**
      * Returns a "Generation Qualifier" name component.  If more than one
      * such component exists, the topmost one is returned.
      *
      * @return "GENERATION=" component of the name, if any.
      */
    public String getGeneration() throws IOException {
        DerValue attr = findAttribute(GENERATIONQUALIFIER_OID);

        return getString(attr);
    }

    
Returns an "IP address" name component.  If more than one
such component exists, the topmost one is returned.

Returns:"IP=" component of the name, if any.
/**
     * Returns an "IP address" name component.  If more than one
     * such component exists, the topmost one is returned.
     *
     * @return "IP=" component of the name, if any.
     */
    public String getIP() throws IOException {
        DerValue attr = findAttribute(ipAddress_oid);

        return getString(attr);
    }

    
Returns a string form of the X.500 distinguished name.
The format of the string is from RFC 1779. The returned string
may contain non-standardised keywords for more readability
(keywords from RFCs 1779, 2253, and 5280).

/**
     * Returns a string form of the X.500 distinguished name.
     * The format of the string is from RFC 1779. The returned string
     * may contain non-standardised keywords for more readability
     * (keywords from RFCs 1779, 2253, and 5280).
     */
    public String toString() {
        if (dn == null) {
            generateDN();
        }
        return dn;
    }

    
Returns a string form of the X.500 distinguished name
using the algorithm defined in RFC 1779. Only standard attribute type
keywords defined in RFC 1779 are emitted.

/**
     * Returns a string form of the X.500 distinguished name
     * using the algorithm defined in RFC 1779. Only standard attribute type
     * keywords defined in RFC 1779 are emitted.
     */
    public String getRFC1779Name() {
        return getRFC1779Name(Collections.<String, String>emptyMap());
    }

    
Returns a string form of the X.500 distinguished name
using the algorithm defined in RFC 1779. Attribute type
keywords defined in RFC 1779 are emitted, as well as additional
keywords contained in the OID/keyword map.

/**
     * Returns a string form of the X.500 distinguished name
     * using the algorithm defined in RFC 1779. Attribute type
     * keywords defined in RFC 1779 are emitted, as well as additional
     * keywords contained in the OID/keyword map.
     */
    public String getRFC1779Name(Map<String, String> oidMap)
        throws IllegalArgumentException {
        if (oidMap.isEmpty()) {
            // return cached result
            if (rfc1779Dn != null) {
                return rfc1779Dn;
            } else {
                rfc1779Dn = generateRFC1779DN(oidMap);
                return rfc1779Dn;
            }
        }
        return generateRFC1779DN(oidMap);
    }

    
Returns a string form of the X.500 distinguished name
using the algorithm defined in RFC 2253. Only standard attribute type
keywords defined in RFC 2253 are emitted.

/**
     * Returns a string form of the X.500 distinguished name
     * using the algorithm defined in RFC 2253. Only standard attribute type
     * keywords defined in RFC 2253 are emitted.
     */
    public String getRFC2253Name() {
        return getRFC2253Name(Collections.<String, String>emptyMap());
    }

    
Returns a string form of the X.500 distinguished name
using the algorithm defined in RFC 2253. Attribute type
keywords defined in RFC 2253 are emitted, as well as additional
keywords contained in the OID/keyword map.

/**
     * Returns a string form of the X.500 distinguished name
     * using the algorithm defined in RFC 2253. Attribute type
     * keywords defined in RFC 2253 are emitted, as well as additional
     * keywords contained in the OID/keyword map.
     */
    public String getRFC2253Name(Map<String, String> oidMap) {
        /* check for and return cached name */
        if (oidMap.isEmpty()) {
            if (rfc2253Dn != null) {
                return rfc2253Dn;
            } else {
                rfc2253Dn = generateRFC2253DN(oidMap);
                return rfc2253Dn;
            }
        }
        return generateRFC2253DN(oidMap);
    }

    private String generateRFC2253DN(Map<String, String> oidMap) {
        /*
         * Section 2.1 : if the RDNSequence is an empty sequence
         * the result is the empty or zero length string.
         */
        if (names.length == 0) {
            return "";
        }

        /*
         * 2.1 (continued) : Otherwise, the output consists of the string
         * encodings of each RelativeDistinguishedName in the RDNSequence
         * (according to 2.2), starting with the last element of the sequence
         * and moving backwards toward the first.
         *
         * The encodings of adjoining RelativeDistinguishedNames are separated
         * by a comma character (',' ASCII 44).
         */
        StringBuilder fullname = new StringBuilder(48);
        for (int i = names.length - 1; i >= 0; i--) {
            if (i < names.length - 1) {
                fullname.append(',');
            }
            fullname.append(names[i].toRFC2253String(oidMap));
        }
        return fullname.toString();
    }

    public String getRFC2253CanonicalName() {
        /* check for and return cached name */
        if (canonicalDn != null) {
            return canonicalDn;
        }
        /*
         * Section 2.1 : if the RDNSequence is an empty sequence
         * the result is the empty or zero length string.
         */
        if (names.length == 0) {
            canonicalDn = "";
            return canonicalDn;
        }

        /*
         * 2.1 (continued) : Otherwise, the output consists of the string
         * encodings of each RelativeDistinguishedName in the RDNSequence
         * (according to 2.2), starting with the last element of the sequence
         * and moving backwards toward the first.
         *
         * The encodings of adjoining RelativeDistinguishedNames are separated
         * by a comma character (',' ASCII 44).
         */
        StringBuilder fullname = new StringBuilder(48);
        for (int i = names.length - 1; i >= 0; i--) {
            if (i < names.length - 1) {
                fullname.append(',');
            }
            fullname.append(names[i].toRFC2253String(true));
        }
        canonicalDn = fullname.toString();
        return canonicalDn;
    }

    
Returns the value of toString().  This call is needed to
implement the java.security.Principal interface.

/**
     * Returns the value of toString().  This call is needed to
     * implement the java.security.Principal interface.
     */
    public String getName() { return toString(); }

    
Find the first instance of this attribute in a "top down"
search of all the attributes in the name.

/**
     * Find the first instance of this attribute in a "top down"
     * search of all the attributes in the name.
     */
    private DerValue findAttribute(ObjectIdentifier attribute) {
        if (names != null) {
            for (int i = 0; i < names.length; i++) {
                DerValue value = names[i].findAttribute(attribute);
                if (value != null) {
                    return value;
                }
            }
        }
        return null;
    }

    
Find the most specific ("last") attribute of the given
type.

/**
     * Find the most specific ("last") attribute of the given
     * type.
     */
    public DerValue findMostSpecificAttribute(ObjectIdentifier attribute) {
        if (names != null) {
            for (int i = names.length - 1; i >= 0; i--) {
                DerValue value = names[i].findAttribute(attribute);
                if (value != null) {
                    return value;
                }
            }
        }
        return null;
    }

    /****************************************************************/

    private void parseDER(DerInputStream in) throws IOException {
        //
        // X.500 names are a "SEQUENCE OF" RDNs, which means zero or
        // more and order matters.  We scan them in order, which
        // conventionally is big-endian.
        //
        DerValue[] nameseq = null;
        byte[] derBytes = in.toByteArray();

        try {
            nameseq = in.getSequence(5);
        } catch (IOException ioe) {
            if (derBytes == null) {
                nameseq = null;
            } else {
                DerValue derVal = new DerValue(DerValue.tag_Sequence,
                                           derBytes);
                derBytes = derVal.toByteArray();
                nameseq = new DerInputStream(derBytes).getSequence(5);
            }
        }

        if (nameseq == null) {
            names = new RDN[0];
        } else {
            names = new RDN[nameseq.length];
            for (int i = 0; i < nameseq.length; i++) {
                names[i] = new RDN(nameseq[i]);
            }
        }
    }

    
Encodes the name in DER-encoded form.

Params:
  • out – where to put the DER-encoded X.500 name
Deprecated:Use encode() instead
/**
     * Encodes the name in DER-encoded form.
     *
     * @deprecated Use encode() instead
     * @param out where to put the DER-encoded X.500 name
     */
    @Deprecated
    public void emit(DerOutputStream out) throws IOException {
        encode(out);
    }

    
Encodes the name in DER-encoded form.

Params:
  • out – where to put the DER-encoded X.500 name
/**
     * Encodes the name in DER-encoded form.
     *
     * @param out where to put the DER-encoded X.500 name
     */
    public void encode(DerOutputStream out) throws IOException {
        DerOutputStream tmp = new DerOutputStream();
        for (int i = 0; i < names.length; i++) {
            names[i].encode(tmp);
        }
        out.write(DerValue.tag_Sequence, tmp);
    }

    
Returned the encoding as an uncloned byte array. Callers must
guarantee that they neither modify it not expose it to untrusted
code.

/**
     * Returned the encoding as an uncloned byte array. Callers must
     * guarantee that they neither modify it not expose it to untrusted
     * code.
     */
    public byte[] getEncodedInternal() throws IOException {
        if (encoded == null) {
            DerOutputStream     out = new DerOutputStream();
            DerOutputStream     tmp = new DerOutputStream();
            for (int i = 0; i < names.length; i++) {
                names[i].encode(tmp);
            }
            out.write(DerValue.tag_Sequence, tmp);
            encoded = out.toByteArray();
        }
        return encoded;
    }

    
Gets the name in DER-encoded form.

Returns:the DER encoded byte array of this name.
/**
     * Gets the name in DER-encoded form.
     *
     * @return the DER encoded byte array of this name.
     */
    public byte[] getEncoded() throws IOException {
        return getEncodedInternal().clone();
    }

    /*
     * Parses a Distinguished Name (DN) in printable representation.
     *
     * According to RFC 1779, RDNs in a DN are separated by comma.
     * The following examples show both methods of quoting a comma, so that it
     * is not considered a separator:
     *
     *     O="Sue, Grabbit and Runn" or
     *     O=Sue\, Grabbit and Runn
     *
     * This method can parse RFC 1779, 2253 or 4514 DNs and non-standard 5280
     * keywords. Additional keywords can be specified in the keyword/OID map.
     */
    private void parseDN(String input, Map<String, String> keywordMap)
        throws IOException {
        if (input == null || input.length() == 0) {
            names = new RDN[0];
            return;
        }

        List<RDN> dnVector = new ArrayList<>();
        int dnOffset = 0;
        int rdnEnd;
        String rdnString;
        int quoteCount = 0;

        String dnString = input;

        int searchOffset = 0;
        int nextComma = dnString.indexOf(',');
        int nextSemiColon = dnString.indexOf(';');
        while (nextComma >=0 || nextSemiColon >=0) {

            if (nextSemiColon < 0) {
                rdnEnd = nextComma;
            } else if (nextComma < 0) {
                rdnEnd = nextSemiColon;
            } else {
                rdnEnd = Math.min(nextComma, nextSemiColon);
            }
            quoteCount += countQuotes(dnString, searchOffset, rdnEnd);

            /*
             * We have encountered an RDN delimiter (comma or a semicolon).
             * If the comma or semicolon in the RDN under consideration is
             * preceded by a backslash (escape), or by a double quote, it
             * is part of the RDN. Otherwise, it is used as a separator, to
             * delimit the RDN under consideration from any subsequent RDNs.
             */
            if (rdnEnd >= 0 && quoteCount != 1 &&
                !escaped(rdnEnd, searchOffset, dnString)) {

                /*
                 * Comma/semicolon is a separator
                 */
                rdnString = dnString.substring(dnOffset, rdnEnd);

                // Parse RDN, and store it in vector
                RDN rdn = new RDN(rdnString, keywordMap);
                dnVector.add(rdn);

                // Increase the offset
                dnOffset = rdnEnd + 1;

                // Set quote counter back to zero
                quoteCount = 0;
            }

            searchOffset = rdnEnd + 1;
            nextComma = dnString.indexOf(',', searchOffset);
            nextSemiColon = dnString.indexOf(';', searchOffset);
        }

        // Parse last or only RDN, and store it in vector
        rdnString = dnString.substring(dnOffset);
        RDN rdn = new RDN(rdnString, keywordMap);
        dnVector.add(rdn);

        /*
         * Store the vector elements as an array of RDNs
         * NOTE: It's only on output that little-endian ordering is used.
         */
        Collections.reverse(dnVector);
        names = dnVector.toArray(new RDN[dnVector.size()]);
    }

    private void parseRFC2253DN(String dnString) throws IOException {
        if (dnString.length() == 0) {
            names = new RDN[0];
            return;
         }

         List<RDN> dnVector = new ArrayList<>();
         int dnOffset = 0;
         String rdnString;
         int searchOffset = 0;
         int rdnEnd = dnString.indexOf(',');
         while (rdnEnd >=0) {
             /*
              * We have encountered an RDN delimiter (comma).
              * If the comma in the RDN under consideration is
              * preceded by a backslash (escape), it
              * is part of the RDN. Otherwise, it is used as a separator, to
              * delimit the RDN under consideration from any subsequent RDNs.
              */
             if (rdnEnd > 0 && !escaped(rdnEnd, searchOffset, dnString)) {

                 /*
                  * Comma is a separator
                  */
                 rdnString = dnString.substring(dnOffset, rdnEnd);

                 // Parse RDN, and store it in vector
                 RDN rdn = new RDN(rdnString, "RFC2253");
                 dnVector.add(rdn);

                 // Increase the offset
                 dnOffset = rdnEnd + 1;
             }

             searchOffset = rdnEnd + 1;
             rdnEnd = dnString.indexOf(',', searchOffset);
         }

         // Parse last or only RDN, and store it in vector
         rdnString = dnString.substring(dnOffset);
         RDN rdn = new RDN(rdnString, "RFC2253");
         dnVector.add(rdn);

         /*
          * Store the vector elements as an array of RDNs
          * NOTE: It's only on output that little-endian ordering is used.
          */
         Collections.reverse(dnVector);
         names = dnVector.toArray(new RDN[dnVector.size()]);
    }

    /*
     * Counts double quotes in string.
     * Escaped quotes are ignored.
     */
    static int countQuotes(String string, int from, int to) {
        int count = 0;

        for (int i = from; i < to; i++) {
            if ((string.charAt(i) == '"' && i == from) ||
                (string.charAt(i) == '"' && string.charAt(i-1) != '\\')) {
                count++;
            }
        }

        return count;
    }

    private static boolean escaped
                (int rdnEnd, int searchOffset, String dnString) {

        if (rdnEnd == 1 && dnString.charAt(rdnEnd - 1) == '\\') {

            //  case 1:
            //  \,

            return true;

        } else if (rdnEnd > 1 && dnString.charAt(rdnEnd - 1) == '\\' &&
                dnString.charAt(rdnEnd - 2) != '\\') {

            //  case 2:
            //  foo\,

            return true;

        } else if (rdnEnd > 1 && dnString.charAt(rdnEnd - 1) == '\\' &&
                dnString.charAt(rdnEnd - 2) == '\\') {

            //  case 3:
            //  foo\\\\\,

            int count = 0;
            rdnEnd--;   // back up to last backSlash
            while (rdnEnd >= searchOffset) {
                if (dnString.charAt(rdnEnd) == '\\') {
                    count++;    // count consecutive backslashes
                }
                rdnEnd--;
            }

            // if count is odd, then rdnEnd is escaped
            return (count % 2) != 0 ? true : false;

        } else {
            return false;
        }
    }

    /*
     * Dump the printable form of a distinguished name.  Each relative
     * name is separated from the next by a ",", and assertions in the
     * relative names have "label=value" syntax.
     *
     * Uses RFC 1779 syntax (i.e. little-endian, comma separators)
     */
    private void generateDN() {
        if (names.length == 1) {
            dn = names[0].toString();
            return;
        }

        StringBuilder sb = new StringBuilder(48);
        if (names != null) {
            for (int i = names.length - 1; i >= 0; i--) {
                if (i != names.length - 1) {
                    sb.append(", ");
                }
                sb.append(names[i].toString());
            }
        }
        dn = sb.toString();
    }

    /*
     * Dump the printable form of a distinguished name.  Each relative
     * name is separated from the next by a ",", and assertions in the
     * relative names have "label=value" syntax.
     *
     * Uses RFC 1779 syntax (i.e. little-endian, comma separators)
     * Valid keywords from RFC 1779 are used. Additional keywords can be
     * specified in the OID/keyword map.
     */
    private String generateRFC1779DN(Map<String, String> oidMap) {
        if (names.length == 1) {
            return names[0].toRFC1779String(oidMap);
        }

        StringBuilder sb = new StringBuilder(48);
        if (names != null) {
            for (int i = names.length - 1; i >= 0; i--) {
                if (i != names.length - 1) {
                    sb.append(", ");
                }
                sb.append(names[i].toRFC1779String(oidMap));
            }
        }
        return sb.toString();
    }

    /****************************************************************/

    /*
     * Selected OIDs from X.520
     * Includes all those specified in RFC 5280 as MUST or SHOULD
     * be recognized
     */
    private static final int commonName_data[] = { 2, 5, 4, 3 };
    private static final int SURNAME_DATA[] = { 2, 5, 4, 4 };
    private static final int SERIALNUMBER_DATA[] = { 2, 5, 4, 5 };
    private static final int countryName_data[] = { 2, 5, 4, 6 };
    private static final int localityName_data[] = { 2, 5, 4, 7 };
    private static final int stateName_data[] = { 2, 5, 4, 8 };
    private static final int streetAddress_data[] = { 2, 5, 4, 9 };
    private static final int orgName_data[] = { 2, 5, 4, 10 };
    private static final int orgUnitName_data[] = { 2, 5, 4, 11 };
    private static final int title_data[] = { 2, 5, 4, 12 };
    private static final int GIVENNAME_DATA[] = { 2, 5, 4, 42 };
    private static final int INITIALS_DATA[] = { 2, 5, 4, 43 };
    private static final int GENERATIONQUALIFIER_DATA[] = { 2, 5, 4, 44 };
    private static final int DNQUALIFIER_DATA[] = { 2, 5, 4, 46 };

    private static final int ipAddress_data[] = { 1, 3, 6, 1, 4, 1, 42, 2, 11, 2, 1 };
    private static final int DOMAIN_COMPONENT_DATA[] =
        { 0, 9, 2342, 19200300, 100, 1, 25 };
    private static final int userid_data[] =
        { 0, 9, 2342, 19200300, 100, 1, 1 };


    // OID for the "CN=" attribute, denoting a person's common name.
    public static final ObjectIdentifier commonName_oid =
            ObjectIdentifier.newInternal(commonName_data);

    // OID for the "SERIALNUMBER=" attribute, denoting a serial number for.
    // a name. Do not confuse with PKCS#9 issuerAndSerialNumber or the
    // certificate serial number.
    public static final ObjectIdentifier SERIALNUMBER_OID =
            ObjectIdentifier.newInternal(SERIALNUMBER_DATA);

    // OID for the "C=" attribute, denoting a country.
    public static final ObjectIdentifier countryName_oid =
            ObjectIdentifier.newInternal(countryName_data);

    // OID for the "L=" attribute, denoting a locality (such as a city).
    public static final ObjectIdentifier localityName_oid =
            ObjectIdentifier.newInternal(localityName_data);

    // OID for the "O=" attribute, denoting an organization name.
    public static final ObjectIdentifier orgName_oid =
            ObjectIdentifier.newInternal(orgName_data);

    // OID for the "OU=" attribute, denoting an organizational unit name.
    public static final ObjectIdentifier orgUnitName_oid =
            ObjectIdentifier.newInternal(orgUnitName_data);

    // OID for the "S=" attribute, denoting a state (such as Delaware).
    public static final ObjectIdentifier stateName_oid =
            ObjectIdentifier.newInternal(stateName_data);

    // OID for the "STREET=" attribute, denoting a street address.
    public static final ObjectIdentifier streetAddress_oid =
            ObjectIdentifier.newInternal(streetAddress_data);

    // OID for the "T=" attribute, denoting a person's title.
    public static final ObjectIdentifier title_oid =
            ObjectIdentifier.newInternal(title_data);

    // OID for the "DNQUALIFIER=" or "DNQ=" attribute, denoting DN
    // disambiguating information.
    public static final ObjectIdentifier DNQUALIFIER_OID =
            ObjectIdentifier.newInternal(DNQUALIFIER_DATA);

    // OID for the "SURNAME=" attribute, denoting a person's surname.
    public static final ObjectIdentifier SURNAME_OID =
            ObjectIdentifier.newInternal(SURNAME_DATA);

    // OID for the "GIVENNAME=" attribute, denoting a person's given name.
    public static final ObjectIdentifier GIVENNAME_OID =
            ObjectIdentifier.newInternal(GIVENNAME_DATA);

    // OID for the "INITIALS=" attribute, denoting a person's initials.
    public static final ObjectIdentifier INITIALS_OID =
            ObjectIdentifier.newInternal(INITIALS_DATA);

    // OID for the "GENERATION=" attribute, denoting Jr., II, etc.
    public static final ObjectIdentifier GENERATIONQUALIFIER_OID =
            ObjectIdentifier.newInternal(GENERATIONQUALIFIER_DATA);

    // OIDs from other sources which show up in X.500 names we
    // expect to deal with often.
    //
    // OID for "IP=" IP address attributes, used with SKIP.
    public static final ObjectIdentifier ipAddress_oid =
            ObjectIdentifier.newInternal(ipAddress_data);

    // Domain component OID from RFC 1274, RFC 2247, RFC 5280.
    //
    // OID for "DC=" domain component attributes, used with DNSNames in DN
    // format.
    public static final ObjectIdentifier DOMAIN_COMPONENT_OID =
            ObjectIdentifier.newInternal(DOMAIN_COMPONENT_DATA);

    // OID for "UID=" denoting a user id, defined in RFCs 1274 & 2798.
    public static final ObjectIdentifier userid_oid =
            ObjectIdentifier.newInternal(userid_data);

    
Return constraint type:
    
  
  • NAME_DIFF_TYPE = -1: input name is different type from this name
      (i.e. does not constrain)
  
  • NAME_MATCH = 0: input name matches this name
  
  • NAME_NARROWS = 1: input name narrows this name
  
  • NAME_WIDENS = 2: input name widens this name
  
  • NAME_SAME_TYPE = 3: input name does not match or narrow this name,
&       but is same type

.  These results are used in checking NameConstraints during
certification path verification.

Params:
  • inputName – to be checked for being constrained
Throws:
@returnsconstraint type above
/**
     * Return constraint type:<ul>
     *   <li>NAME_DIFF_TYPE = -1: input name is different type from this name
     *       (i.e. does not constrain)
     *   <li>NAME_MATCH = 0: input name matches this name
     *   <li>NAME_NARROWS = 1: input name narrows this name
     *   <li>NAME_WIDENS = 2: input name widens this name
     *   <li>NAME_SAME_TYPE = 3: input name does not match or narrow this name,
     &       but is same type
     * </ul>.  These results are used in checking NameConstraints during
     * certification path verification.
     *
     * @param inputName to be checked for being constrained
     * @returns constraint type above
     * @throws UnsupportedOperationException if name is not exact match, but
     *         narrowing and widening are not supported for this name type.
     */
    public int constrains(GeneralNameInterface inputName)
            throws UnsupportedOperationException {
        int constraintType;
        if (inputName == null) {
            constraintType = NAME_DIFF_TYPE;
        } else if (inputName.getType() != NAME_DIRECTORY) {
            constraintType = NAME_DIFF_TYPE;
        } else { // type == NAME_DIRECTORY
            X500Name inputX500 = (X500Name)inputName;
            if (inputX500.equals(this)) {
                constraintType = NAME_MATCH;
            } else if (inputX500.names.length == 0) {
                constraintType = NAME_WIDENS;
            } else if (this.names.length == 0) {
                constraintType = NAME_NARROWS;
            } else if (inputX500.isWithinSubtree(this)) {
                constraintType = NAME_NARROWS;
            } else if (isWithinSubtree(inputX500)) {
                constraintType = NAME_WIDENS;
            } else {
                constraintType = NAME_SAME_TYPE;
            }
        }
        return constraintType;
    }

    
Compares this name with another and determines if
it is within the subtree of the other. Useful for
checking against the name constraints extension.

Returns:true iff this name is within the subtree of other.
/**
     * Compares this name with another and determines if
     * it is within the subtree of the other. Useful for
     * checking against the name constraints extension.
     *
     * @return true iff this name is within the subtree of other.
     */
    private boolean isWithinSubtree(X500Name other) {
        if (this == other) {
            return true;
        }
        if (other == null) {
            return false;
        }
        if (other.names.length == 0) {
            return true;
        }
        if (this.names.length == 0) {
            return false;
        }
        if (names.length < other.names.length) {
            return false;
        }
        for (int i = 0; i < other.names.length; i++) {
            if (!names[i].equals(other.names[i])) {
                return false;
            }
        }
        return true;
    }

    
Return subtree depth of this name for purposes of determining
NameConstraints minimum and maximum bounds and for calculating
path lengths in name subtrees.

Throws:
@returnsdistance of name from root
/**
     * Return subtree depth of this name for purposes of determining
     * NameConstraints minimum and maximum bounds and for calculating
     * path lengths in name subtrees.
     *
     * @returns distance of name from root
     * @throws UnsupportedOperationException if not supported for this name type
     */
    public int subtreeDepth() throws UnsupportedOperationException {
        return names.length;
    }

    
Return lowest common ancestor of this name and other name

Params:
  • other – another X500Name
Returns:X500Name of lowest common ancestor; null if none
/**
     * Return lowest common ancestor of this name and other name
     *
     * @param other another X500Name
     * @return X500Name of lowest common ancestor; null if none
     */
    public X500Name commonAncestor(X500Name other) {

        if (other == null) {
            return null;
        }
        int otherLen = other.names.length;
        int thisLen = this.names.length;
        if (thisLen == 0 || otherLen == 0) {
            return null;
        }
        int minLen = (thisLen < otherLen) ? thisLen: otherLen;

        //Compare names from highest RDN down the naming tree
        //Note that these are stored in RDN[0]...
        int i=0;
        for (; i < minLen; i++) {
            if (!names[i].equals(other.names[i])) {
                if (i == 0) {
                    return null;
                } else {
                    break;
                }
            }
        }

        //Copy matching RDNs into new RDN array
        RDN[] ancestor = new RDN[i];
        for (int j=0; j < i; j++) {
            ancestor[j] = names[j];
        }

        X500Name commonAncestor = null;
        try {
            commonAncestor = new X500Name(ancestor);
        } catch (IOException ioe) {
            return null;
        }
        return commonAncestor;
    }

    
Constructor object for use by asX500Principal().

/**
     * Constructor object for use by asX500Principal().
     */
    private static final Constructor<X500Principal> principalConstructor;

    
Field object for use by asX500Name().

/**
     * Field object for use by asX500Name().
     */
    private static final Field principalField;

    
Retrieve the Constructor and Field we need for reflective access
and make them accessible.

/**
     * Retrieve the Constructor and Field we need for reflective access
     * and make them accessible.
     */
    static {
        PrivilegedExceptionAction<Object[]> pa =
                new PrivilegedExceptionAction<Object[]>() {
            public Object[] run() throws Exception {
                Class<X500Principal> pClass = X500Principal.class;
                Class<?>[] args = new Class<?>[] { X500Name.class };
                Constructor<X500Principal> cons = pClass.getDeclaredConstructor(args);
                cons.setAccessible(true);
                Field field = pClass.getDeclaredField("thisX500Name");
                field.setAccessible(true);
                return new Object[] {cons, field};
            }
        };
        try {
            Object[] result = AccessController.doPrivileged(pa);
            @SuppressWarnings("unchecked")
            Constructor<X500Principal> constr =
                    (Constructor<X500Principal>)result[0];
            principalConstructor = constr;
            principalField = (Field)result[1];
        } catch (Exception e) {
            throw (InternalError)new InternalError("Could not obtain "
                + "X500Principal access").initCause(e);
        }
    }

    
Get an X500Principal backed by this X500Name.
Note that we are using privileged reflection to access the hidden
package private constructor in X500Principal.

/**
     * Get an X500Principal backed by this X500Name.
     *
     * Note that we are using privileged reflection to access the hidden
     * package private constructor in X500Principal.
     */
    public X500Principal asX500Principal() {
        if (x500Principal == null) {
            try {
                Object[] args = new Object[] {this};
                x500Principal = principalConstructor.newInstance(args);
            } catch (Exception e) {
                throw new RuntimeException("Unexpected exception", e);
            }
        }
        return x500Principal;
    }

    
Get the X500Name contained in the given X500Principal.
Note that the X500Name is retrieved using reflection.

/**
     * Get the X500Name contained in the given X500Principal.
     *
     * Note that the X500Name is retrieved using reflection.
     */
    public static X500Name asX500Name(X500Principal p) {
        try {
            X500Name name = (X500Name)principalField.get(p);
            name.x500Principal = p;
            return name;
        } catch (Exception e) {
            throw new RuntimeException("Unexpected exception", e);
        }
    }

}