code: public void append(String str, int off, int len) {
  	int restLength = buffer.length - pos;
  	if (len < restLength) {
  	    str.getChars(off, off + len, buffer, pos);
  	    pos += len;
  	}
  	else {
  	    str.getChars(off, off + restLength, buffer, pos);
  	    curr.next = new Entity(buffer);
  	    curr = curr.next;
  	    length += buffer.length;
  	    buffer = new char[(buffer.length > len - restLength) ? buffer.length : len - restLength];
  
  	    str.getChars(off + restLength, off + len, buffer, 0);
  	    pos = len - restLength;
  
  	}
      }
docs: method to append a part of a String
  
  @param str string to get part from
  @param off start index on the string
  @param len length of the sequenz to get from string