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Transcript of © Blackboard, Inc. All rights reserved. Developing Blackboard Building Blocks: Getting Started John...
© Blackboard, Inc. All rights reserved.
Developing Blackboard Building Blocks: Getting StartedJohn KnightSenior EngineerBlackboard Inc.
July 18th
Overview
» Goals» Blackboard® Building Blocks® Technology» Java/JSP Development Tools» Blackboard Building Block Development – Tools
and Techniques
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 July 18, 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 July 18, 2005. Blackboard, in its sole discretion, may delay or cancel the release of any product or functionality described in this presentation.
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
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
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
Blackboard Building Blocks Architecture
Core Services
Data Objects
Business Layer(JSP, Servlet, Struts)
View Layer(JSP, Servlet, Tag Library)
Log
Security
Config Persistence
Session
I18N VXI
Context Plug-ins
Anatomy of a Blackboard Building Block
Package (.war/.zip file)
Platform Descriptor
Blackboard Manifest
Web Resources
Libraries
web.xml (Servlets)
Servlets, JSP (Java)
.class, .jar files (Java)
bb-manifest.xml
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
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
The Process
PreliminaryFeaturePlanning
EnvironmentSet-up
Initial Build/Install
Compile Stage Package
Compile Stage Deploy
Iterate
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
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
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
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
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
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
Organizing the workspace...
Example – The Directories
Compiled Classes
Config Files
Library Files
Java Source
“Prep” Directory
JSP/HTML/Image
Automating the environment...
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
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
Example – A Simplified Build File
Init properties, files
Compile Java Files
Copy files to staging
Create .war file
Copy to install
Example – Build File
Example – Eclipse Integration
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
Using the tools...
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
Example – JUnit Integration
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, notably, the security manager is not enabled by default
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
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
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
Debugging – Connecting
Debugging – Connected
Debugging – Connected
Conclusion
» Planning your build environment can help ease some of the headache of Blackboard Building Block development
» Use tools that help automate the process
Resources
» Ant: http://ant.apache.org/» Eclipse: http://www.eclipse.org/ » Java/JDK: http://java.sun.com/ » Blackboard Building Blocks:
http://buildingblocks.blackboard.com/
Questions