@Override public void makeImmutable(){
  if (mutable) {
    if (attrs != null) {
      Iterator iter=attrs.iterator();
      while (iter.hasNext()) {
        Attribute attr=(Attribute)iter.next();
        attr.makeImmutable();
      }
      attrs=Collections.unmodifiableList(attrs);
    }
    if (encAttrs != null) {
      encAttrs=Collections.unmodifiableList(encAttrs);
    }
    mutable=false;
  }
}

@ Override public void makeImmutable ( ) { if ( mutable ) { if ( attrs != null ) { Iterator iter = attrs . iterator ( ) ; while ( iter . hasNext ( ) ) { Attribute attr = ( Attribute ) iter . next ( ) ; attr . makeImmutable ( ) ; } attrs = Collections . unmodifiableList ( attrs ) ; } if ( encAttrs != null ) { encAttrs = Collections . unmodifiableList ( encAttrs ) ; } mutable = false ; } }
makes the object immutable .
