Convert string underscore case do camelCase

underscoreToCamelCase.groovy

//Code forked from John Moore (http://grails.1312388.n4.nabble.com/template/NamlServlet.jtp?macro=user_nodes&user=111982)
public static String propertyNameCase(String s) { 
     // Handle null and empty strings. 
     if(s == null || s.trim().length() == 0 ) return s; 
     String str; 
     if (s.indexOf('_') != -1) { 

         StringBuilder buf = new StringBuilder(); 
         String[] tokens = s.split("_"); 
         for (String token: tokens) { 
             if (token == null || token.length() == 0) continue; 
             buf.append(token.substring(0, 1).toUpperCase()).append(token.substring(1).toLowerCase()); 
         } 
         str = buf.toString(); 
     } else { 
         str = s; 
     } 
     if (str.length()>  0) { 
         str = str.substring(0, 1).toLowerCase() + str.substring(1); 
     } 
     return str; 
}

assert underscoreToCamelCase("TEST_METHOD") = "testMethod"