Re: [classad-users] XML Parsing

["Giuseppe Avellino" <giuseppe.avellino@xxxxxxxxxx>]

Thank you a lot
Giuseppe

----- Original Message ----- 
From: "Marvin Solomon" <solomon@xxxxxxxxxxx>
To: <classad-users@xxxxxxxxxxx>; <giuseppe.avellino@xxxxxxxxxx>
Sent: Monday, May 10, 2004 2:49 PM
Subject: Re: [classad-users] XML Parsing


>
> Giuseppe Avellino wrote:
>  > Hi,
>  > I am trying to use new Java Classad library 2.1 to handle record
expressions
>  > in XML format. These record expressions are written to files and then
read
>  > with an instance of ClassAdParser class.
>  > To write record expression to a file, what I do is:
>  >
>  > StringWriter stringWriter = new StringWriter();
>  > ClassAdWriter classAdWriter = new ClassAdWriter(stringWriter,
>  > ClassAdWriter.XML);
>  > classAdWriter.enableFormatFlags(ClassAdWriter.MULTI_LINE_LISTS);
>  > classAdWriter.enableFormatFlags(ClassAdWriter.MULTI_LINE_ADS);
>  >
>  > classAdWriter.print(recordExpr);
>  > String xmlText = stringWriter.toString();
>  > (... method to write the String representation to a file...)
>  >
>  > recordExpr is a RecorExpr created in some way.
>  > This produce an XML file (N.B. please check: when I do this, closing
>  > </classad> tag is missing - it could be a bug)
>
> The ClassAdWriter cannot add the closing </classads> tag until you call
> close(), because it has no way of knowing whether you intend to add more
> output.  Insert
>
>      stringWriter.close();
>
> before the line
>
>      String xmlText = stringWriter.toString();
>
> and this problem will go away.
>
>  >
>  > To read from a file I do:
>  >
>  > FileInputStream fis = null;
>  > try {
>  >     fis = new FileInputStream(file);
>  > } catch (Exception ex) {
>  >     (...)
>  > }
>  > ClassAdParser parser = new ClassAdParser(fis, ClassAdParser.XML);
>  > PrintStream ps = new PrintStream(new ByteArrayOutputStream());
>  > parser.setErrorStream(ps);
>  > Expr expr = parser.parse();
>  > ListExpr listExpr = (ListExpr) expr;
>  > RecordExpr recordExpr = new RecordExpr();
>  > if (listExpr != null) {
>  >       recordExpr = (RecordExpr) listExpr.sub(0);
>  > }
>  >
>  > This works quite good, but I would like to know how I can get error
messages
>  > (a String) during parsing (e.g. telling me that a tag is missing in the
>  > file). What I need is to get exception.getMessage() and not the entire
stack
>  > trace as I can do using setErrorStream(PrintStream dest) method of the
>  > ClassAdParser class.
>
> You can catch the exception text by calling the method
> ClassAdParser.setErrorStream(PrintStream dest).
>
>          OutputStream errs = new ByteArrayOutputStream();
>          parser.setErrorStream(new PrintStream(errs));
>          Expr expr = parser.parse();
>          System.out.println(" + expr);
>          System.out.println(" + errs);
>
> [There really ought to be a version setErrorStream(Writer).  I'll add that
> to the next release.]
>
> This will give you the entire stack trace.  If you just want the detail
message
>
>      End of entity not allowed; an end tag is missing.
>
> add the call
>
>      parser.setVerbosity(1);
>
> before the call to parser.parse().
>
>  > With last version of Classad library I was using a modified version of
the
>  > class ClassAdSAXHandler providing a method to get a String containing
error
>  > messages. I think I could do the same for new release, but I need a dtd
file
>  > to avoid getting errors about XML elements and attribute missing
definitions
>  > (XML representation created by ClassAdWriter print() method doesn't
contain
>  > SYSTEM to specify a dtd file to use - so these kind of errors are
reported).
>  > I know some tags are changed, so old condor.dtd file has to be
modified.
>  > If it is not possible to produce a String representation of parsing
errors
>  > using standard handler, could you tell me how I can get a new
condor.dtd
>  > file (I can modify the last one on my one, but it could be better to
have
>  > the one you provide, if any).
>
> The dtd and the xmlSchema are included in the reference manual, but I
don't
> understand why you need them for what you're trying to do.
>
>  >
>  > I thank you in advace
>  >
>  > cheers
>  > -----
>  > Giuseppe Avellino
>  > Grid R&D Group
>  > Government and Institutions Division
>  >
>  > DATAMAT  S.p.A.
>  > Via Laurentina, 760 ­ I - 00143 Rome ­ Italy
>  > http://www.datamat.it
>  >
>  > mailto: giuseppe.avellino@xxxxxxxxxx
>  > Phone:  +39 06 5027 4587 (direct)  +39 06 5027 4571 (secretary)
>  > Fax:      +39 06 5027 2500
>  >
>  >
>  > Condor Classads Info:
>  > http://www.cs.wisc.edu/condor/classad/
>
> Ciao,
>
> Marvin Solomon                  Professor
> Computer Sciences Department    University of Wisconsin
> 1210 W. Dayton St.              Madison WI, 53706-1685, USA
> (608) 263-2844                  solomon@xxxxxxxxxxx
>
> Condor Classads Info:
> http://www.cs.wisc.edu/condor/classad/
>
>


Condor Classads Info:
http://www.cs.wisc.edu/condor/classad/