move usernameCnPattern initialization and definition

Author: Vladimir Kotal

plugins/LdapPlugin/src/opengrok/auth/plugin/LdapUserPlugin.java

@@ -47,6 +47,7 @@ public class LdapUserPlugin extends AbstractLdapPlugin {
     protected static final String OBJECT_CLASS = "objectclass";
 
     private String objectClass;
+    private Pattern usernameCnPattern = Pattern.compile("(cn=[a-zA-Z_]+)");
 
     private boolean isAlphanumeric(String str) {
         for (int i = 0; i < str.length(); i++) {
@@ -59,8 +60,6 @@ private boolean isAlphanumeric(String str) {
         return true;
     }
 
-    private Pattern usernameCnPattern = null;
-    
     @Override
     public void load(Map<String, Object> parameters) {
         super.load(parameters);
@@ -75,8 +74,6 @@ public void load(Map<String, Object> parameters) {
                     "' contains non-alphanumeric characters");
         }
 
-        usernameCnPattern = Pattern.compile("(cn=[a-zA-Z_]+)");
-        
         LOGGER.log(Level.FINE, "LdapUser plugin loaded with objectclass={0}",
                 objectClass);
     }