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Using XML

Using XML. In ViPER and More. XML. Direct access to information, without worrying about parsing. XML Information Set XML provides a way to access information independent of access, format, etc. XML is just a serialization of a set of information arranged in a tree. viper config descriptor

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Using XML

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  1. Using XML In ViPER and More

  2. XML • Direct access to information, without worrying about parsing. • XML Information Set • XML provides a way to access information independent of access, format, etc. • XML is just a serialization of a set of information arranged in a tree.

  3. viper config descriptor descriptor data sourcefile filename=“file.mpg” file object ViPER Tree

  4. ViPER File Format <?xml version="1.0" encoding="UTF-8"?> <viper xmlns="http://lamp.cfar.umd.edu/viper" xmlns:data="http://lamp.cfar.umd.edu/viperdata"> <config> <descriptor name="Information" type="FILE"> <attribute name="SOURCEDIR" dynamic="false" type="svalue"/> </descriptor> </config> <data> <sourcefile filename="comm-001_00001.jpg" > <file name="Information" id="0" framespan="0:0"> <attribute name="SOURCEDIR"><data:svalue value="/fs/lampa/FaceTextDB/JPEG/advertisements" /> </attribute> </file> </sourcefile> </data> </viper>

  5. Accessing Via XPath • Get data from a specific file • /viper/data/sourcefile[@filename=“f.mpg”] • Gets the sourcefile node • //sourcefile[@fname=“f.mpg]//bbox • Gets all bbox nodes

  6. Matlab with Java % Add xerces.jar to classpath.txt (find using 'which classpath.txt') % need to restart matlab after changing import org.apache.xerces.parsers.* org.w3c.dom.*; import java.lang.String org.xml.sax.*; input = InputSource('C:\MATLAB6p1\work\advertisements.xml'); parser = DOMParser; parser.setFeature('http://apache.org/xml/features/validation/schema', 0) parser.parse(input); doc = parser.getDocument; sfs = doc.getElementsByTagName('sourcefile') files = cell(sfs.getLength, 1); i = 0; while i < sfs.getLength fileattr = sfs.item(i).getAttributes.getNamedItem('filename'); i = i + 1; files(i) = fileattr.getValue; end

  7. Perl use XML::LibXML; my $parser = XML::LibXML->new(); my $tree = $parser->parse_file($datafiles[0]); my $root = $tree->getDocumentElement; foreach my $source ($root->findnodes('sourcefile')){ my $image = $source->findvalue('@filename'); foreach my $d ($source->findnodes('content|object')){ [$startFrame, $endFrame] = split(/:/,$d->findvalue('@framespan')); foreach my $shape ($d->findnodes(lc($attribType))) { $orig_x = $shape->findvalue( ‘@x' ); $orig_y = $shape->findvalue( ‘@y' );

  8. C with libxml2 #include <libxml/xmlmemory.h> #include <libxml/parser.h> ---- xmlDocPtr doc = = xmlParseFile(‘truth.xml’); if (doc == NULL) return(NULL); xmlNodePtr cur = xmlDocGetRootElement(doc); xmlNsPtr viperns = xmlSearchNsByHref(doc, cur, (const xmlChar *) "http://lamp.cfar.umd.edu/viper"); cur = cur->xmlChildrenNode; while (cur != NULL) { if ((!strcmp(cur->name, “config”)) && (cur->ns == viperns)) parseConfig (doc, viperns, cur); else if ((!strcmp(cur->name, “data”)) && (cur->ns == viperns)) parseData (doc, viperns, cur); cur = cur->next; } xmlCleanupParser();

  9. XML Databases • Uses existing tools to access persistent data • DOM and XPath • XQuery and XUpdate • Many different implementations • Open Source: Apache Xindice, eXist • Proprietary:TextML, X-Hive, • Relational: MS SQL, Oracle

  10. XSL:Transformations • The idea is to look at the incoming data as a tree, using XPath, and select various nodes to copy to the output. • While the output does not have to be XML, the input and the document itself must be well formed. • On system 7, ‘testXSLT’ runs stylesheets.

  11. XSLT <?xml version=“1.0” encoding=“UTF-8”?> <xsl:stylesheet version=“1.0” xmlns:xsl=“http://www.w3.org/1999/XSL/Transform” xmlns:gtf=“http://lamp.cfar.umd.edu/viper” xmlns:data=“http://lamp.cfar.umd.edu/viperdata” xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <xsl:strip-space elements="gtf:viper"/> <xsl:output method="xml" omit-xml-declaration="yes"/> <!– continued -->

  12. XSLT <xsl:template match="/gtf:viper"> <xsl:text> #VIPER_VERSION_3.0 1 </xsl:text> <xsl:apply-templates select="*/"/> </xsl:template> <xsl:template match="//gtf:sourcefile[starts-with(@filename, 'comm-001')]"> <xsl:value-of select="@filename" /> <xsl:text> </xsl:text> </xsl:template> </xsl:stylesheet>

  13. Supported in the majority of browsers in use today. Basic styling. Hopefully will reduce reliance on HTML tables as a way to lay out web pages. <style type="text/css"> p { font-size: 12pt; line-height: 18pt; } p:first-letter { font-size: 200%; float: left; } </style> CSS-1

  14. CSS-2 • Added support for pagination, including widow and orphan control, page breaks, and margins. • Aural style sheets for voice browsing. • Can be applied directly to XML. • Possible to do some multi-column layout.

  15. CSS-3 • Modularized • Through Ruby, support for Japanese, Arabic, etc. • Multi-column layout • Support for other W3C specs, like • SVG • MathML • SMIL

  16. XSL:FO • Basically, the idea is to put CSS-2 in an XML dialect, and use XPath and other XML technologies to make printed media look nice. • Extremely verbose – designed to be generated from semantic markup. • However, its lack of semantics leads Opera CTO Lie to call them “Harmful.” • Additions include footnotes, hyphenation, odd/even pages, citations for indices and tables of contents. • RenderX, Apache FOP

  17. Defining an XML Dialect • Document Type Definitions • Simple, BNF type definition of tags, attributes, and how they may be arranged. • Schema • XML based replacement for non-XML DTDs. • Complex. • Define data types, and associate them with tag names. • Rule based constriction • Schematron

  18. ViPER Schema <?xml version="1.0" encoding="UTF-8"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://lamp.cfar.umd.edu/viper" xmlns:viper="http://lamp.cfar.umd.edu/viper" elementFormDefault="qualified"> <xsd:element name="viper" type="viper:viperType"/> <xsd:complexType name="viperType"> <xsd:sequence> <xsd:element name="config" type="viper:configType"/> <xsd:element name="data" type="viper:dataType" minOccurs="0"/> </xsd:sequence> </xsd:complexType>

  19. ViPER Data Schema <xsd:schema xmlns:xsd=“http://www.w3.org/2001/XMLSchema” targetNamespace=“http://lamp.cfar.umd.edu/viperdata” xmlns:viperdata=“http://lamp.cfar.umd.edu/viperdata” xmlns:viper=“http://lamp.cfar.umd.edu/viper” elementFormDefault=“qualified”> <xsd:import namespace=“http://lamp.cfar.umd.edu/viper” schemaLocation=“file:viper.xsd” /> <xsd:element name="point" substitutionGroup="viper:null"> <xsd:complexType><xsd:complexContent> <xsd:extension base="viper:descriptorAttributeData"> <xsd:attribute name="x" type="xsd:integer"/> <xsd:attribute name="y" type="xsd:integer"/> </xsd:extension> </xsd:complexContent></xsd:complexType> </xsd:element>

  20. MPEG-7 • Based on XML-Schema. • Extensions to deal better with video type data, including matrix data types, etc. • Designed to work with any level of description, from low level to high. • W3C has only a working draft for DOM access to schemas, so using generic MPEG-7 documents is currently difficult.

  21. www.xml.com O'Reilly's XML resource www.w3.org The standards themselves, and lots of good links to implementations. xml.apache.org DOM, SAX, and XSLT for C and Java xmlsoft.org libxml creators msdn.microsoft.com/xml MS-XML parser is the one to use on Windows. mpeg.telecomitalialab.com MPEG-7 Working Group pyxml.sourceforge.net Using xml with Python. okmij.org/ftp/Scheme/xml.html Using XML with Scheme. Resources

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