David Withers wrote:
> Alan Williams wrote:
>> David Withers wrote:
>> [snip]
>>
>> Hello,
>>
>>> After investigating some more I've found that although the XStream docs
>>> say "If a new field is added to the class, deserializing an old version
>>> will leave the field uninitialized", this is not the case. String fields
>>> are initialized to null, even if you set a default value for the field.
>> What is happening? Are you saying that new fields are initialized to
>> null? If so, isn't a possible workaround for this to alter the
>> configuration bean so that when you do a getX it checks if x is null
>> and, if so, sets it to a value?
>
> If it's a new field that's not in the serialized file then yes, it's
> initialized to null, even though I'm setting a value when I declare the
> field, e.g. private String csvDelimiter = ",";
>
> So yes, the workaround in this case is:
>
> public String getCsvDelimiter() {
> return outputFormat == null ? "," : csvDelimiter;
> }
>
>
>>> If you add an enum field then an exception is thrown (which is the
>>> problem I'm hitting).
>> What is throwing the exception?
>
> XStream. I'm guessing that it creates to object for the field and then
> sets the value from the serialized xml. However you can't create enums
> without knowing the value.
Actually I'm wrong there. It seems that because the class is created
without calling a constructor any values that appear to be assigned as
part of the field declaration actually aren't assigned.
Oh well, at least I have a workaround now.
David.
--
David Withers
School of Computer Science, University of Manchester,
Oxford Road, Manchester, M13 9PL, UK.
+44 (0)161 275 0683
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