ldap/src/main/java/org/springframework/security/ldap/authentication/AbstractLdapAuthenticator.java
protected List<String> getUserDns(String username) {
		if (userDnFormat == null) {
			return Collections.emptyList();
		}

		List<String> userDns = new ArrayList<>(userDnFormat.length);
		String[] args = new String[] { LdapEncoder.nameEncode(username) };

		synchronized (userDnFormat) {
			for (MessageFormat formatter : userDnFormat) {
				userDns.add(formatter.format(args));
			}
		}

		return userDns;
	}
protected List<String> getUserDns(String username) {
		if (userDnFormat == null) {
			return Collections.emptyList();
		}

		List<String> userDns = new ArrayList<>(userDnFormat.length);
		String[] args = new String[] { LdapEncoder.nameEncode(username) };

		synchronized (userDnFormat) {
			for (MessageFormat formatter : userDnFormat) {
				userDns.add(formatter.format(args));
			}
		}

		return userDns;
	}
protected List < String > getUserDns ( String username ) { if ( userDnFormat == null ) { return Collections . emptyList ( ) ; } List < String > userDns = new ArrayList <> ( userDnFormat . length ) ; String [ ] args = new String [ ] { LdapEncoder . nameEncode ( username ) } ; synchronized ( userDnFormat ) { for ( MessageFormat formatter : userDnFormat ) { userDns . add ( formatter . format ( args ) ) ; } } return userDns ; }
Builds list of possible DNs for the user, worked out from the
<tt>userDnPatterns</tt> property.

@param username the user's login name

@return the list of possible DN matches, empty if <tt>userDnPatterns</tt> wasn't
set.
Builds list of possible DNs for the user worked out from the <tt > userDnPatterns< / tt > property .