You could also just look at using an XMLStreamWriter or XMLEventWriter, which is part of the StAX API, not Axiom (although Axiom using StAX under the covers), e.g.
OutputStream os = ...; XMLStreamWriter writer = XMLOutputFactory.newInstance().createXMLStreamWriter(os); writer.writeStartDocument(...); ... os.flush(); -----Original Message----- From: Tammy Dugan [mailto:[EMAIL PROTECTED] Sent: Thursday, March 15, 2007 8:29 AM To: [email protected] Subject: Re: [AXIOM] How to serialize axiom document without building objects in memory I guess what I am trying to figure out is how much work it takes to get this kind of streaming working with Axiom and whether I am just better off using our StringDom implementation. It doesn't sound like there is anything in the axiom api by default to support this kind of streaming without creating my own implementations of certain classes. If that is the case, I would rather use our implementation that has been tested to work for our purposes. Thanks, Tammy Ryan Nelsestuen wrote: > I've had some luck getting this to work by implementing an OMDataSource that > doesn't start writing XML until it is passed a writer and then using it to > create an OMSourcedElementImpl. It sort of depends on the semantics of what > you are doing, and you have to be careful as to what methods get called on > the OMSourcedElementImpl (it doesn't seem to take much to cause the whole > thing to inflate - try to avoid doing anything that causes the getReader() > method to get called before you are ready to start sending stuff out the > door), but we've managed to get true streaming to work using Axis2/Axiom, > which saves a lot of transient memory. > > -----Original Message----- > From: Tammy Dugan [mailto:[EMAIL PROTECTED] > Sent: Thursday, March 15, 2007 7:03 AM > To: [email protected] > Subject: Re: [AXIOM] How to serialize axiom document without building > objects in memory > > Before we started looking at axiom, we created a class called StringDom > that extends the w3c dom classes. Each time an appendChild is called, > this dom implementation writes the child to an outputstream/writer. That > way, when we are building a large dom, the elements are not actually > stored in memory but are directly flushed to the outputstream/writer. Of > course, the disadvantage of this technique is that the dom elements must > be appended in the exact order they will be written to output. My > question is whether axiom allows the same kind of absolutely direct > serialization when a child is appended to a parent? If so, how do I do it? > > Thanks, > > Tammy > > Punnoose, Roshan wrote: > >> Tammy, >> >> I'm not exactly sure what you are trying to do... But the >> serialzeAndConsume(...) should not hold it the element in memory. >> >> Check the implementation of the Writer, and also check if the >> serialize(...) method will work. >> >> If none of this works, then what version of axis/axiom are you using? >> >> Roshan Punnoose >> Phone: 301-497-6039 >> >> -----Original Message----- >> From: Tammy Dugan [mailto:[EMAIL PROTECTED] >> Sent: Wednesday, March 14, 2007 2:55 PM >> To: [email protected] >> Subject: [AXIOM] How to serialize axiom document without building >> objects in memory >> >> I have the following code: >> >> new Thread(new ReadDeferred(writer, (OMElement) >> returnData.createRawDataOutputFromTable(doc, >> inputDatasetId, >> outputDatasetId, type, false) >> )).start(); >> ; >> writer.close(); >> >> class ReadDeferred >> implements Runnable >> { >> Writer writer = null; >> OMElement topElement = null; >> public ReadDeferred(Writer writer, OMElement topElement) >> { >> this.writer = writer; >> this.topElement = topElement; >> } >> >> public void run() >> { >> try >> { >> topElement.serializeAndConsume(writer); >> } >> catch (Exception ex) >> { >> InitializationServlet.error("", ex); >> } >> } >> } >> >> >> I am trying to flush the output of createRawDataOutputFromTable directly >> >> to a file without creating a dom tree. The createRawDataOutputFromTable >> method builds an OMDocument using a series of append child statements. >> The above code still holds the whole dom tree in memory before it writes >> >> to a file. Is there a way I can prevent this? I essentially want every >> appendChild to write the child to the file. >> >> >> Tammy >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> For additional commands, e-mail: [EMAIL PROTECTED] >> > > -- Tammy Dugan Computer Programmer Regenstrief Institute, Inc. 1050 Wishard Blvd., RG5 Indianapolis, IN 46202 (317) 630 - 7346 Confidentiality Notice: The contents of this message and any files transmitted with it may contain confidential and/or privileged information and are intended solely for the use of the named addressee(s). Additionally, the information contained herein may have been disclosed to you from medical records with confidentiality protected by federal and state laws. 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