Compare two FixMessages in QuickFIXJ

I need to compare two fix messages (say two ExecutionReports) in QuickFIXJ.

Let's call them er1 and er2

Now, what I mean by comparing them is that a bunch of fields must be identical. for instance I care that tag 55, tag 207, tag 1 are the same. but not others.

It seems to me that the only way to do so is to write something as expensive (performance-wise) as this:

public static boolean compare(ExecutionReport er1,ExecutionReport er2) 
{
   StringField sf1 = new StringField(55);
   StringField sf2 = new StringField(55);

   er.getField(sf1);
   er.getField(sf2);

   if (sf1.getValue().equals(sf2.getValue())==false) return false;

   ... // continue with all of the other fields
   ... // in the same way

}

Am I missing something ? can somebody suggest a better/faster approach ?