XML for Java Developers G22.3033-002 Session 1 - Main Theme Markup Language Technologies (Part I) Dr. Jean-Claude Franchitti New York University Computer Science Department Courant Institute of Mathematical Sciences 1 Agenda n XML Generics n Course Logistics, Structure and Objectives n History of Meta-Markup Languages n XML Applications: Markup Languages n XML Information Modeling Applications n XML-Based Architectures n XML and Java n XML Development Tools n Summary n Class Project n Readings n Assignment #1a 2 XML Generics n XML means eXtensible Markup Language n XML expresses the structure of information (i.e., document content) separately from its presentation n XSL style sheets are used to convert documents to a presentation format that can be processed by a target presentation device (e.g., HTML in the case of legacy browsers) n Document Type Definitions (DTDs) or XML schemas are used to describe and validate content 3 1 Course Logistics n Course Web Site n http://cs.nyu.edu/courses/summer01/G22.3033- 002/index.htm n http://www.nyu.edu/classes/jcf/g22.3033-002/ n Password: xmljava n Review syllabus n Textbooks n XML Development with Java 2 n Professional Java XML n XML and Java, Developing Web Applications 4 Knowledge Required n Know how to ftp files, send e-mail, and load URLs into a Web browser n Reasonable knowledge of HTML n Be able to write a basic HTML page including links, images, and text using a text editor n Be able to place a page on a web server n Advanced Java programming experience 5 Knowledge Not Required n SGML n Programming in Perl, or any language other than Java n Cascading Style Sheets and other HTML advanced features 6 2 Other Useful Knowledge n Web server configuration and the HTTP protocol n JavaScript n C programming n Database theory (normalization rules) n SGML (basic knowledge) n Some knowledge of international character sets 7 History of Meta-Markup Languages n SGML (see http://www.w3c.org) n Complex and expensive n HTML n Tim Berners-Lee (Cern), 1990 n Simple replacement to SGML n Lacked the flexibility and adaptability of XML n W3C XML working group n Jon Bosak (Sun), 1996 n SGML strengths + HTML simplicity 8 History of Meta-Markup Languages (continued) n XML 1.0 Specification n Tim Bray n Language simple enough for programmers to implement n Language not limited to English n Documents easy for search engine n CML, Jumbo, MathML n XLL (1997), CDF (1997), XSL (1997), MSXSL (1998), XML-Data, Mozilla, etc. 9 3 Why XML? n Domain specific markup language n Common data format n Simple, pure Unicode text n Well-documented n Data interchange n Open Financial Exchange (OFX) n XML non copyrighted n Support of portable structured text data as most electronic information is text-based 10 Related Technologies n JavaSoft’s Java API for XML parsing (JAXP) n Java bindings to SAX, and DOM APIs n HTML n CSS, CSS2, and CSS3 n XSL n well formed XML documents n URLs and URIs n resource v.s. location n Linking (XLL) n Unicode 11 Applications of XML: Markup Languages n XML helps define sets of rules for forming semantic tags that break documents into parts n XML is a Metamarkup language n Not a markup language restricted to a fixed set of tags n Can make up tags as you go along n XML Tags can be documented in a DTD n i.e., a domain specific syntax and vocabulary (e.g., CML, MathML, etc.) 12 4 HTML Example <dt>Java <dd>by Sun MicroSystem <ul> <li>Publisher: O’Reilly <li>ISBN: 0-777-88888-9 <li>Pages: 900 </ul> <P>The complete documentation.<P> 13 XML Corresponding Structure <book> <title>Java</title> <author>Sun Microsystems</author> <publisher>O’Reilly</publisher> <isbn>0-777-88888-9</isbn> <pages>900</pages> <blurb>The complete documentation</blurb> </book> 14 XML Enables Semantic/Structured Markup Languages n XML describes a document’s structure and meaning n XML does not describe the formatting of the elements n Formatting is added through style sheets n XML document only contains tags describing the content (not the appearance) of the document 15 5 XML Information Modeling Applications (Focus on Complex Structured Document Specification) n Custom and Industry specific Markup Languages with own syntax and vocabulary n CML (Chemical Markup Language) n MathML (Mathematical Markup Language) n CML (Channel Definition Format) n Classic Literature n SMIL (Synchronized Multimedia Integration Language n OSD (Open Software Description) 16 XML-Based Architectures n Presentation-Oriented Publishing Frameworks n XML-Based Application Servers n Message-Oriented Middleware Frameworks n Web Services Frameworks n Peer to Peer (P2P) Computing n XML-Based eServices Protocols and Architectures 17 XML POP Frameworks (Focus on Content Management and Publishing) n Requirements: n XML parser n XSL processor n Document repository n Collection of document DTDs or schema n Collection of XSL style sheets n Parsing & processing can be client or server-based n Samples server-side XML technology: n Perl & CGI (http://www.perl.com/CPAN) n Java servlets (http://www.alphaworks.ibm.com , www.apache.org) n ASPs (http://www.beyondhtml.com/rocket) 18 6 XML POP Packaged Solutions n Enterprise Information Portal (EIP) toolkits n e.g., DataChannel’s XML framework n Structured content management and retrieval systems n e.g., n Vignette’s StoryServer n Gauss Interprise’s VIP’XML-Gateway n Poet’s Content Management Suite n Chrystal Software’s Astoria 19 XML MOM Applications n Component-based modeling n e.g., XML Metadata Interchange (XMI) n Enterprise Application Integration n Business-to-Customer (B2C) Applications n e.g., e-Commerce n Business-to-Business (B2B) Applications n e.g., n WebMethods n Bluestone’s XML-Server, n eXcelon 2.0 n XMLSolutions’ ExeterXML server 20 Java-enabled XML Technologies n XML provides a universal syntax for Java semantics (behavior) n Portable, reusable data descriptions in XML n Portable Java code that makes the data behave in various ways n XML standard extension n Basic plumbing that translates XML into Java n parser, namespace support in the parser, simple API for XML (SAX), and document object model (DOM) n XML data binding standard extension 21 7 XML and Java Standards n XML includes is a family of technologies n XSL, XML Schema, XML Query, XPath, XPointer, XLink, DOM, RDF, CSS, XSL, XHTML, XML Signature, MathML, SMIL, SVG, etc. n Review the current state of the XML standards at http://www.w3c.org/XML n Review the current state of Java Technology and XML (JAXP) standards at http://java.sun.com/XML n Review the Java binding to DOM 2.0 at http://www.w3.org/TR/2000/REC-DOM-Level-2- Core-20001113/java-binding.zip 22 XML Development Tools n Read and write XML documents n XML Editors n e.g., Wattle Software’s XMLWriter, SoftQuad’s Xmetal, Vervet Logic’s XML Pro, eXcelon Stylus, XML Spy n XML well-formedness and/or validation Processors n e.g., IBM’s XML4J, Apache’s XercesJ, Oracle Parser, Java Project X processor, James Clark’s Expat parser, Microsoft MSXML n XML Browsers n e.g., IE5 23 Summary n XML is a metamarkup language n XML tags describe the structure and semantics of a document’s content (not the format of the content) n XML addresses SGML’s complexity and HTML’s inadequacies n Applications of XML for information modeling exist in various domains (chemistry, math, multimedia, etc.) 24 8 Summary (continued) n XML supports MOM and POP applications n XML supports the Web Services Infrastructure n XML and Java complements each other n Java-enabled XML technology is available in the market today n Standards for integrating XML and Java are being developed 25 Class Project n Project Description n The project will focus on “multi-channel online community platforms”, and will consist of providing custom XML-based services to support the various aspects of a chosen eBusiness application implemented on such platforms (e.g., “community -based shopping”). Examples of useful services to support these platforms may include synchronized multimedia presentation viewing, and “offline” chat capabilities. A sample specification of an online community platform for a virtual university eBusiness application will be provided for illustration purpose. 26 Readings n Readings n XML Development with Java 2: Chapter 1 n Professional Java XML: Chapter 1 n XML and Java: Chapter 1, Appendix C n Handouts posted on the course web site n Explore brief review of XML at XML in 10 points n Read article at XMLJ2EE n Review XML 1.0 (Second edition), Namespaces, and the XML activity statement at W3C n Project Frameworks Setup (ongoing) n Apache’s Web Server, TomCat, and Cocoon 27 n Apache’s Xerces, Xalan 9 Assignment n Assignment #1a: n Explore the textbooks’ CDs, and the textbook references to XML tools n Install and experiment with XML editors. Settle on a tool you feel comfortable using, and come up with a small XML application that demonstrates the use of that tool. Write a short report that uses your sample application to document your findings and recommendations with respect to selection criteria in support of XML editors 28 Next Session: Markup Language Technologies (Part II) n Current state of the XML standard n Advanced XML applications n XML style Specification Languages 29 10.