Prof. Dr. Wolfgang May

• Module M.Inf.1802, 4 SWS, 6 ECTS-credits; it is graded (=benotet)

Course Description

The practical training builds upon the lecture Semistructured Data and XML. It introduces XML application programming based on Java and on Web Services.

Prerequisites:

• Successful participation in the module Semistructured Data and XML or comparable good knowledge in XML, and
• Successful participation in the "General Programming Lab/Allgemeines Programmierpraktikum" (or an equivalent course on Programming+Java).

• Date and Time: Mon 14-18
• Room: IFI 2.101 (North Campus) online via StudIP->BBB
• The course takes place in groups of 3-4 persons. There are usually 5 units: XPath/XQuery, XSLT (both based on the material of the lecture), XML and Java I (DOM/SAX/StAX), XML and Java II (JAXB and Digester), and Web Services (with an application project).
• For every unit, there is an exercise sheet which will be discussed with one of the supervisors, maybe also the monday slots can be used for this.
• Every monday: Optional live online "course meetings" with BigBlueButton. Course materials are provided as recordings, so the meetings consist of short comments to the new topic and questions&answers and hands-on support for the ongoing exercise sheet.
• Materials for self-studying are provided as PDF slides and as videos (from winter term 2020/21)
• Please also read the general and technical information about DBIS virtual teaching.

Documentation: use the slides from the SSD/XML lecture (the full slide set can be found here; Sections 1-8 were the material of the lecture, the rest is intended for the practical course) and the W3C documentation linked below. For practical exercises, the XML software is installed in the IFI CIP Pool. Short descriptions of the software to be used can be found here.

Prospective Time Schedule

Part I: Review of basics, concepts and languages around XML that should be known from the XML lecture.

• Kickoff Meeting (attendance required):
  Mo 28.10.: 14-16: Introduction, Formalities.
  Rocket Chat of the XML lab course.
• 28.10. cont'd: 1. Unit: Exercises to XPath, XQuery (including user-defined functions)
  Slides: XPath, Slides: XQuery from the lecture.
  In addition to the slides, the W3C material serves as technical documentation for the languages:
  W3C XPath 3.0, W3C Recommendation, 2014.
  W3C XQuery 3.0, W3C Recommendation 2014.
  W3C XPath and XQuery Functions and Operators 3.0, W3C Recommendation 2014.
  Exercises: Exercise Sheet 1: XQuery
  Discussion until 22.11.
• 4.11. 14:15 optional: hands-on-meeting
• 11.11. 2. Unit: XSLT
  Optional BBB-Meeting, short comments, mainly then hands-on support for XQuery Exercises
  Slides: XSLT
  W3C XSLT 3.0, W3C Recommendation 8 June 2017.
  Exercise Sheet 2: XSLT
• 18.11.: Discussion of Exercise Sheet 1 (XPath/XQuery) (Grp.1)
• 21.11.: Discussion of Exercise Sheet 1 (XPath/XQuery) (Grp.2) ?

Part II: XML and Java

• 25.11.: 3. Unit: XML and Java I: DOM, SAX, StAX (and hands-on support for XSLT exercises)
  Slides: XML and Java I
  Short online meeting in StudIP/BBB; video material see below, Questions and Answers, Hands-on-meeting.
  Code fragments from the slides: to download
  Video: see StudIP WS20/21: Meeting "XMLP-2020-11-30-dom-sax-stax"
  
  • Exercise Sheet 3: DOM/SAX/StAX [ catdata.xml ]
  • The exercise sheet contains 7 exercises:
  • Exercises 1 and 2 are smaller "warmup" exercises for DOM and SAX/StAX, they should be done groupwise such that everybody gets into the new material. The discussion of these exercises will be rather short.
  • Ex. 3 goes a bit deeper into the idea of stream processing of XML and Java threads.
  • Exercises 4-7 handle a "real use case" in different ways. The presentation of these bigger exercises should not just be like "yes, I did it", but to present the solution ideas+strategy, an informative overview of the code and the interesting aspects, and the lessons learnt by doing it.
  • Presentations/Discussion preferably on 9./16.12.2024 (for this, we need probably two appointments).
• 2.12.: Discussion of Exercise Sheet 2 (XSLT)
• 9.12.: 4. Unit: XML and Java II: JAXB, Digester
  Slides: XML and Java II.
  JAXB uses XML Schema: Slides XML Schema
  Code fragments from the slides: to download (including the readme with the shell commands for JAXB).
  [ (Test 12.12.2022: JAXB works with some warnings on the CIP pool computers). ]
  The Digester jar files can be found in /afs/informatik.uni-goettingen.de/user/d/dbisuser/XML-Tools/Digester (CIP Pool) or here.
  Note: the Digester examples on the slides work in the IFI-Pool only when /afs/informatik.uni-goettingen.de/group/dbis/public/oracle/lib/xmlparserv2.jar is not in the classpath (situation in 2019).
  Video see StudIP WS20/21,
  Exercises: Exercise Sheet 4: JAXB, Digester, HTML processing (groupwise discussion 6.1.2025)
• 9.12. afterwards: Discussion of some exercises from Exercise Sheet 3.
• 16.12.2024: Discussion of the rest of Exercise Sheet 3.

Part III: Project/Scenario

• 13.1.2025: 5. Unit: Web-Server-Technology, HTTP, Servlets.
  Video: see StudIP WS20/21,
  Slides: Web Services
  Installation instructions for tomcat
  XQuery Demo Servlet as .war-file
  Servlet Demo Source Code
  DBIS Git with sources for XQuery (and SQL) Web Services
  (note to myself: add all XML-P-participants in gitlab to the group dbis/Teaching/XML-Praktikum-Teilnehmer)
  For using other people's Web Services, you need HTTP internet access to their tomcat/apaches. This is usually not possible "behind" an internet provider (dynamic IP addresses). For this, you can use the institute's shell servers (with ssh forwarding) and install tomcats there (if you are on the same shellX, then bind your individual tomcats to 8080, 8081, 8082 ...):

     * login.stud.informatik.uni.goettingen.de -> shell1.cip.loc  ... shell8.cip.loc
  

• Exercise Sheet 5: Web Services, Project: University Information Services - EXA, StudIP, FlexNow
  • Ex. Sheet 5
• 13.1.: Discussion of Exercise Sheet 4.
• 20.1.: Project Meeting
• 27.1.: Project Meeting, Discussion of the Exercises of Exercise Sheet 5
• 3.2.: Project Meeting