Developing Blackboard Building Blocks™: Getting Started

1. Developing Blackboard Building Blocks™: Getting Started Presented By Bob Alcorn Blackboard Inc. April 12, 2005

2. Overview • Goals • Blackboard Building Blocks Technology • Java/JSP Development Tools • Blackboard Building Block Development – Tools and Techniques

3. Now a word from our lawyers… Any statements in this presentation about future expectations, plans and prospects for Blackboard and other statements containing the words "believes," "anticipates," "plans," "expects," "will," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the factors discussed in the "Risk Factors" section of our most recent 10-K filed with the SEC. In addition, the forward-looking statements included in this press release represent the Company's views as of April 11, 2005. The Company anticipates that subsequent events and developments will cause the Company's views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing the Company's views as of any date subsequent to April 11, 2005. Blackboard, in its sole discretion, may delay or cancel the release of any product or functionality described in this presentation.

4. Audience • Basic to Intermediate Java developer • Java/JSP/Servlet development is assumed • Blackboard Building Block development is not assumed, but is helpful • Familiarity with, but not necessarily expertise in, current Java development tools

5. Goals • Focus on process and environment, rather than Blackboard Building Block technology • Cover a selection of tools that are available to build Blackboard Building Blocks • Describe techniques and practices that will make the development process easier

6. Blackboard Building Blocks Technology • Extensibility mechanism for Blackboard® • Provide drop-in functionality, or... • Provide a bridge to an external system • Standards-based • Blackboard Building Blocks are Java webapps with additional metadata • Rely on/integrate with embedded Tomcat engine

7. Security Session Context Plug-ins Log Config Persistence I18N VXI Blackboard Building Blocks Architecture Business Layer (JSP, Servlet, Struts) View Layer (JSP, Servlet, Tag Library) Data Objects Core Services

8. Anatomy of a Blackboard Building Block Package (.war/.zip file) web.xml (Servlets) Platform Descriptor bb-manifest.xml Blackboard Manifest Servlets, JSP (Java) Web Resources .class, .jar files (Java) Libraries

9. The Process • Feature Planning • Defines what you’ll need in terms of entry points • Set up the build environment • Local Blackboard server works best • Perform an initial build • Get entry points defined • Install the Blackboard Building Block • Iterate • Build/rebuild • Redeploy

10. The Build Stages • Compile • Custom .java files compiled into .class files • Stage • Web app structure is created from other components • Package • Web app structure is zipped into the .war file • Deploy • An alternate to “package”, depending on the cycle

11. The Process Preliminary Feature Planning Environment Set-up Initial Build/ Install Compile Stage Package Iterate Compile Stage Deploy

12. The Process • Initial Install vs. Re-deploy • Initial Install reads manifest and establishes the entry points • Re-deploy simply makes Blackboard Building Block inactive, then makes it Available again • Cycles webapp, reloads classes • Inactive/Available cycle unnecessary for JSP changes

13. Example – The Build Environment • JDK 1.4/5.x – The core Java library you’ll need • Eclipse 3.x – An IDE for editing/debugging/formatting • Ant 1.6.2 – A tool to automate many of the tasks (within Eclipse and via shell automation) • ... All Freely Available

14. The Tools – JDK • Version is dependent on which Blackboard install is targeted • 6.0.11 and higher supports 1.4.x • 6.3 and higher require 5.x • New language features are extremely nice

15. The Tools – Ant • An Apache Software Foundation project • Not bound to Blackboard release • Samples developed against 1.6.2, but should work against earlier versions

16. The Tools – Eclipse • Java IDE with substantial productivity features • Ant integration • Refactoring • JUnit integration • Plugins (e.g., SCM integration, JSP editing) • You’ll need 3.1 if you’re developing with JDK 5.x

17. The Strategy • Organize the workspace to separate the different types of files you’ll work on • Web Files (JSPs) • Logic Files (.java files, servlets, etc.) • Configuration Files (.tld, .xml) • Etc. • Use a tool that will automate the transformation of each artifact into the next • Build the configuration to support rapid iteration • Use the tools to support unit development, unit testing, and debugging • Better encapsulated, smaller units helps make the iteration easier

18. Organizing the workspace...

19. Example – The Directories Compiled Classes Config Files Library Files Java Source “Prep” Directory JSP/HTML/Image

20. Automating the environment...

21. An Ant Primer • Build utility to manage compile/build tasks and dependencies • Uses XML as the syntax (compare to make, etc). • Core data model: project  target  task • Targets define dependencies and contain tasks • Tasks are the units of work... • Many built-in tasks (javac, jar, copy, etc.) • Easy to customize

22. An Ant Primer • File typically named “build.xml” • Ant will automatically process that file if no file argument is provided • Arguments can include specific targets • Project default target is used if no target is provided. E.g., • c:\projects\sample>ant • c:\projects\sample>ant compile • c:\projects\sample>ant -f alternate.xml compile

23. Example – A Simplified Build File Init properties, files Compile Java Files Copy files to staging Create .war file Copy to install

24. Example – Build File

25. Example – Eclipse Integration

26. Making It Easier • The Starting Block • Server Blackboard Building Block to Install, Cycle, and Uninstall • An Ant task to invoke the Starting Block from your build environment

27. Using the tools...

28. Test Driven Development • Write objects that can be used independently of the container • Re-use • Testability • Get used to writing methods (and tests) corresponding to user interface features

29. Example – JUnit Integration

30. Debugging • A valuable and under-used technique • Avoid System.out.println() like the plague • Limitations actually encourage better practices • If you’re used to stepping through code, and hate the lack of JSP  source correlation, you’ll build better business objects • Caveat: environment is slightly different, notable the security manager is not enabled by default

31. Debugging – How To • Stop the Blackboard Tomcat instance • Open a command line, define the JPDA environment variables • Execute the shell launcher that brings Tomcat up in JPDA mode • Connect with debugger of choice

32. Debugging – How To (Windows) c:\blackboard\apps\tomcat> net stop bb-tomcat c:\blackboard\apps\tomcat> set JPDA_ADDRESS=2222 c:\blackboard\apps\tomcat> set JPDA_TRANSPORT=dt_socket c:\blackboard\apps\tomcat> bin\blackboard-tomcat.bat jpda start

33. Debugging – How To (Unix) /usr/local/blackboard/> ./tools/admin/ServiceController.sh services.appserver.stop /usr/local/blackboard/> export JPDA_ADDRESS=2222 /usr/local/blackboard/> export JPDA_TRANSPORT=dt_socket c:\blackboard\apps\tomcat> ./bin/blackboard-tomcat.sh jpda start

34. Debugging – Connecting

35. Debugging – Connected

36. Debugging – Connected

37. Conclusion • Planning your build environment can help ease some of the headache of Blackboard Building Block development • Use tools that help automate the process

38. Resources • Ant: http://ant.apache.org/ • Eclipse: http://www.eclipse.org/ • Java/JDK: http://java.sun.com/ • Blackboard Building Blocks: http://buildingblocks.blackboard.com/