code: public PdfObject getValue(String v) {
  		switch(fieldType) {
  		case TEXT:
  			return new PdfString(v, PdfObject.TEXT_UNICODE);
  		case DATE:
  			return new PdfDate(PdfDate.decode(v));
  		case NUMBER:
  			return new PdfNumber(v);
  		}
  		throw new IllegalArgumentException(v + " is not an acceptable value for the field " + get(PdfName.N).toString());
  	}
docs: Returns a PdfObject that can be used as the value of a Collection Item.
  @param v	value	the value that has to be changed into a PdfObject (PdfString, PdfDate or PdfNumber)