Re: DefaultDOMWriter

Well, what do you know.  I was actually wondering why ServletResponse 
didn't provide a method to query what the current content type was set 
to.  Check this out for the new Servlet-2.4 spec....
http://tinyurl.com/j4xl


Servlet 2.4 spec says that ServletResponse now gets two more methods, (from 
sections 5.4, 14.2.22) Namely;
     String getContentType();
     void   setCharacterEncoding(String charset)


I wish they'd thought of that a long time ago.  We wouldn't even have this 
problem since we'd be able to check if a content type was set on the 
servlet response and not override it if it was already set....or at least 
do something based on what it is currently set to.

Anyway, I tend to agree with Srini.  DefaultDOMWriter uses XMLC do perform 
output formatting and it has a setOutputOptions(OutputOptions) method.  We 
can query the OutputOptions for the appropriate content-type, or mime-type 
as it is referred to in OutputOptions.  All one has to do is do is....

OutputOptions oo = DefaultDOMWriter.getDefaultOutputOptions(doc);
oo.setMIMEType("application/excel");
DOMWriter dw = new DefaultDOMWriter(oo);
dw.write(node, resp);

The only caveat is that I don't think that getMIMEType() is guaranteed to 
be non-null since it is only there to override the mime type stored in the 
XMLC XMLObject.  So, we could check this value and use it if it is 
non-null, but then do some heuristics to figure out what the appropriate 
mime-type should be otherwise.

Of course, the obvious way to avoid all this is to set the content type 
yourself on the response object, get the writer (or output stream) from the 
response object, and just call...
dw.write(node, writer);

That way, the write(Node, HttpServletResponse) method can continue to do 
its thing, which should work in most cases, and you can either use its 
functionality or bypass it if it doesn't meet your requirements.

Do any of those solutions clear things up for you?

Jake


At 03:37 PM 8/4/2003 -0700, you wrote:
>Thanks Christian and Jake.
>
>I do agree that setting content-type is not such a great idea but, we have 
>html content (a DOM object) that needs to be opened by the MS-excel 
>application. Its more like a shortcut to handling direct excel format. So 
>I set the content-type to "application/excel" even when the content is 
>not, so that the browser forwards it to excel app and then the excel can 
>simply open it as though it were a excel document. I hope that clears it 
>up. Do you know any better way other than to set the content-type?
>
>I think carrying the content type in the OutputOptions is another idea. So 
>I can set it and pass that object to the DOMWriter and the write method 
>could use it to set it in the response object.
>
>Thanks,
>Srini.
>
>Jacob Kjome wrote:
>
>>Hi Srini,
>>
>>At 02:22 PM 8/4/2003 -0700, you wrote:
>>
>>>In the write method of DefaultDOMWriter, the content-type is set without 
>>>regards to what was set before. In my application, I provide a excel 
>>>download using html content. So I need to set the content-type to 
>>>application/excel for some html documents that I spit out. Does anybody 
>>>have any suggestions?
>>>Sorry if this question has already been asked. Please point me in the 
>>>right direction.
>>
>>
>>It is a good question.  I have a question for you.  Why would you use a 
>>content type of "application/excel" for "html content".  if it is "html", 
>>then it isn't an excel document.  Well, I'm probably missing some 
>>details.  That said, I think you are right.   Overriding the content type 
>>in DefaultDOMWriter is probably not a good idea.  I wonder if that code 
>>shouldn't be removed entirely?  Would this cause any problems for 
>>anyone?  I can imagine i might, but I'd like to hear opinions from others.
>>
>>Jake
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