code: public boolean containsPrimary(Property property, String value)
    {
      for (Metadata meta : primary.get(property))
      {
        if (meta.getValue().equals(value))
        {
          return true;
        }
      }
      return false;
    }
docs: Returns <code>true</code> if this metadata set contains a primary
  expression for the given property and the given value
  
  @param property
  a property from a metadata vocabulary
  @param value
  the value to search
  @return <code>true</code> if this metadata set contains a primary
  expression for the given property and value