config-prettyfaces/src/main/java/com/ocpsoft/pretty/faces/el/Expressions.java
public static boolean isEL(final String value)
   {
      if (value == null)
      {
         return false;
      }
      return elPattern.matcher(value).matches();
   }
public static boolean isEL(final String value)
   {
      if (value == null)
      {
         return false;
      }
      return elPattern.matcher(value).matches();
   }
Return true if the value is an EL expression.