RE: Class casting question

[<Vikrant.Verma@alltel.com>]

in the scenario described u can get a classcast if the object returned is an instance of Super and you try to cast it to Sub. use instanceof operator before casting it should help.
-Vikrant

-----Original Message-----
From: Tracy McAbee [mailto:tracy.mcabee@visionarysystemsinc.com]
Sent: Thursday, March 20, 2003 7:13 PM
To: ajug-members@ajug.org
Subject: Class casting question


I have a utility class with a method that parses an XML string (and one that
parses an XML file) and returns a superclass which holds the parsed
information.  I'd like to use this utility for sub-classes as well, without
writing new methods to return each sub-class.  Can it be done?  I know I get
a ClassCastException at runtime when I use::

Sub sub = (Sub)UtilXML.parseXMLSTRING();

which makes sense.  There's got to be a better way, but I'm having a hard
time finding it.

Here's an example of the classes and utility class to which I'm referring:

public class Super (
  // holds parsed values
)

public class Sub extends Super (
  // sub-class of Super
)

public class UtilXML {
  public static Super parseXMLFILE(String fileName, String endTag);
  public static Super parseXMLSTRING(String xml, String endTag);
)

Is there a proper way to deal with this situation?  Just trying to see if
anyone has some ideas...

Thanks.

Tracy McAbee