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Re: Null values in text nodes
On Wed, 22 Nov 2000, Michael Keuchen wrote:
> The program:
> ------------
>
> import org.w3c.dom.*;
> import org.ozoneDB.xml.dom.*;
>
> public class MonsterDOMTest
> {
> public static void main(String[] args)
> {
> DocumentImpl doc = new DocumentImpl();
> Text filledText = new TextImpl();
> ((TextImpl)filledText).init(doc, "testdata");
> System.out.println(filledText.toString());
> Text emptyText = new TextImpl();
> ((TextImpl)emptyText).init(doc, null);
> System.out.println(emptyText.toString()); // line 14
> }
> }
>
> The error message:
> ------------------
>
> Text node: [testdata]
> Exception in thread "main" java.lang.NullPointerException:
> at org.ozoneDB.xml.dom.TextImpl.toString(TextImpl.java:98)
> at MonsterDOMTest.main(MonsterDOMTest.java:14)
>
> The problem is that the value of a TextNode may be set to null without
> problems,
> but this is forbidden by the DOM specification.
> Other parts of the class rely on a non-null value.
>
> Solution:
> ---------
>
> In all init() methods of Nodes that may have values, it has to
> be checked that a value null is stored not as null, but as "".
This just hides an error of the programmer (more exactly: the entity that
created the wrong init() method call) If this is true, then I don't like this
solution. To me throwing an exception seems to be a better solution.
Falko
--
______________________________________________________________________
Falko Braeutigam mailto:falko@smb-tec.com
SMB GmbH http://www.smb-tec.com