© 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