ldap/src/main/java/org/springframework/security/ldap/authentication/AbstractLdapAuthenticator.java
public void setUserDnPatterns(String[] dnPattern) {
		Assert.notNull(dnPattern, "The array of DN patterns cannot be set to null");
		// this.userDnPattern = dnPattern;
		userDnFormat = new MessageFormat[dnPattern.length];

		for (int i = 0; i < dnPattern.length; i++) {
			userDnFormat[i] = new MessageFormat(dnPattern[i]);
		}
	}
public void setUserDnPatterns(String[] dnPattern) {
		Assert.notNull(dnPattern, "The array of DN patterns cannot be set to null");
		// this.userDnPattern = dnPattern;
		userDnFormat = new MessageFormat[dnPattern.length];

		for (int i = 0; i < dnPattern.length; i++) {
			userDnFormat[i] = new MessageFormat(dnPattern[i]);
		}
	}
Sets the pattern which will be used to supply a DN for the user. The pattern should
be the name relative to the root DN. The pattern argument {0} will contain the
username. An example would be "cn={0},ou=people".

@param dnPattern the array of patterns which will be tried when converting a
username to a DN.