A Blackboard Building Block™ Crash Course for Web Developers

Murali Yellepeddy, Architect

Agenda

• Blackboard Building Block Introduction

• Hooks into the platform

• B2 Manager

• Blackboard® API

• Tag libraries

• Security

• Q&A

Introduction

• If you've ever built a webapp for Tomcat®, WebLogic®, WebSphere®, etc Or a portlet for uPorta®l, Liferay®, etc - you've essentially already built a Blackboard Building Block

• Blackboard® itself is nothing more than a bunch of webapps running on Tomcat

Blackboard® Architecture

Client

Bb App Server(s) Bb DB Server

Oracle® /SQL*

Server®

Apache /IIS

Static files .html

Tomcat.jsp pages

/webapp pagesLocale images

Collab Server

chat & virtual classroom

• B2s are most-closely-related to a portlet in that it's a simple webapp with 1 extra XML file that tells Blackboard where your app will hook into it

Blackboard Building Block Contents

webapp

Manifest (XML)

BB-Manifest.XML

• Describes the web application to the Blackboard plug-in manager

– Metadata

• Allows to extend functionality

– Custom Content– Links– Portal Modules– Register to Notifications– Gradable Items

• Security

– Entitlements– Permissions

Basic Structure of a Blackboard-Manifest File

<?xml version="1.0" encoding="ISO-8859-1"?>

<manifest>

<!-- core extension information -->

<plugin>

<!-- general information: name, handle, etc. -->

<http-actions> ... </http-actions>

<!– Register to Notifications -->

<extension-defs> ... </extension-defs>

<!-- Custom Portal Modules -->

<module-defs> ... </module-defs>

<!–- Score Providers -->

<score-providers> ... </score-providers>

Basic Structure of a Blackboard-Manifest File

<!-- custom content handlers -->

<content-handlers>

<content-handler> ... </content-handler>

</content-handlers>

<!-- Tools defined by this extension -->

<application-defs>

<application> ... </application>

</application-defs>

<permissions> ... </permissions>

</plugin>

</manifest>

Example Code

• Hello World Mashup content handler

• Adds a course tool

Blackboard® B2 Manager

What to use to build it..

• Just like a webapp, you can use whichever framework technology you want to use - Struts & Spring are the most common.

• You can also use straight JSPs for the most basic of projects, but using MVC is recommended as a better practice

• Similarly, you can easily add supporting libraries such as those from the Apache Commons projects to avoid reinventing the wheel for common tasks. Note, a lot of libraries already ship with Blackboard® Learn™(check /blackboard/apps/tomcat/lib)

Blackboard® Look & Feel

• Easy to render the user interface using the Blackboard tag libraries - similar to the JSTL libraries (Java) or SharePoint web part Web UI Controls used to render HTML.

• The tag libraries inherit the look/feel, usability, and accessibility of the core product

• You can also roll your own UI using straight HTML if desired

Example Code

Javascript

• Blackboard uses Prototype.

• You can layer additional AJAX technologies on top of it such as Scriptaculous for slick web 2.0-like behavior.

• Would not recommend using JQuery as sometimes Prototype and JQuery don't interact so well. Another one to look at is AjaxTags.

Blackboard® API to Access Blackboard Data

• Base persistence objects are defined in the package, blackboard.persist, with sub-packages including

– announcement– calendar– content– course– gradebook– user

Context vs Persistence

Context tag– Current Session– Current Page– Who am I?– Where am I?

Persistence objects– Permanent Data

Store– Retrieve or

update data– Single objects

• UserId given UserName

– Lists of objects• All users in a

course• All courses for a

user

Permissions

• Wrapper around Java security

• Allows administrators to allow or deny a building block based on what it is trying to access

References

• Documentation and API reference

– http://www.edugarage.com

• Tag libraries: – Current versions on your Blackboard Learn Server

…/blackboard/content/WEB-INF/config/taglibs – Generate documentation (html-format)

https://taglibrarydoc.dev.java.net/

Questions ?

Please provide feedback for this session by emailing DevConFeedback@blackboard.com. 

The subject of the email should be title of this session:

A Building Block Crash Course for Web Developers