Just what is a Building Block

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Just what is a Building Block?
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Rough Plan

• Look at a WAR file
• Java standards
• File structure
• Talk about Manifests

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Definition

• Quoting the Building Block Developers Guide

Building Blocks are an exciting feature in
Blackboard Academic Suite. A Building Block is
an application created by third party developers
that is used to extend the functionality of the
core Blackboard Academic Suite.
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Definition

• A web application which extends or modifies
  Blackboard
• At a minimum the system must be running the
  Enterprise version of Blackboard
• Basic no Building Blocks ?
• Some blocks (e.g. Portal Modules or Content
  System) require particular parts of the
  Blackboard Academic Suite to be installed

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Two Flavours

• Initially you could only write Building Blocks in
  Java
• Now you can also write them using the Microsoft
  .Net framework

• Java building blocks work on any system
• .Net building blocks only work natively on the
  Windows platform, though you could try them by
  also running Mono on your Linux/Unix server
• This workshop is only going to look at Java
  building blocks

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Definition

• A series of files bundled up in a Web Archive
  (like a Zip file)
• Implements a standard file structure Java
  Servlet version 2.2
• http//java.sun.com/products/servlet/2.2/
• http//java.sun.com/products/servlet/2.2/javadoc/i
  ndex.html
• Your Java IDE will build most of this for you ?

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Whats in a WAR file?
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META-INF folder
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WEB-INF folder
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WEB-INF folder
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images folder
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tools folder name up to you!
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Other folders

• You can add any other folders you want, e.g.
• scripts\
• tools2\
• documents\
• If you write any Java classes for your building
  block your IDE should put them in
• WEB-INF\classes\
• If you want to use compiled classes (JAR files)
  these should go in
• WEB-INF\lib\

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Manifest tasks

• Blackboard uses its own special
  filebb-manifest.xml
• This is not part of the Java Servlet standard
• It tells the Blackboard server
• what the building block does
• what its allowed to do (permissions)
• and where it should go

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Manifest tasks

• Specifies the type of Building Block
• Supplies the URLs that the Blackboard server
  needs to call upon the functionality of the
  Building Block

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Key points

• Manifests must be valid XML
• Open in your browser to validate them!
• Must close all quotes and use /gt to end tags
• Important entries
• Vendor id
• Handle
• Permissions
• determines what it is allowed to do on your
  server
• Explicit if you dont list it, it cant do it

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Task

• Dissect these manifests
• Work out what the other fields do
• Which ones would you change for your building
  blocks?
• Some have errors can you spot them?

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