Bundles and Plug-Ins

under construction

Introduction

Explain:

• What is a bundle? Give an example.
• What is OSGi and how does it work?
  • Explain what an Activator is.
• Provide references to tutorials developers new to the concept of bundles can read to get familiar with the topic.

Developing IGB bundles

IGB bundles are OSGi compatible, so they must have an Activator, a class that extends org.osgi.framework.BundleActivator, and they must have a manifest.mf file that is found in the META-INF directory. These are compiled and jarred with all required classes, jars, and resources. The resulting jar is the bundle. This can then be uploaded to the bundle repository. At that point, any one can use the bundle with IGB. IGB uses the Apache Felix OSGi implementation, but this could change, so no Felix specific code should be used. In the Activator class, there is a start() and stop() method that are called when the bundle is activated / deactivated (not installed / uninstalled). This is where you want to put all the code to start and stop the bundle.

In the manifest.mf file, there are several headers that need to be specified - fill in parenthesis below:

Ann's note: the formatting below is weird. Did you copy and paste from an email message?

Ann's note: Please explain how the fields in the manifest map onto what user's see in the Plug-Ins tab.

Import-Package and Require-Bundle don't need to overlap, you can specify a requirement
in one or the other. To have a multi line header, start the continuation line after a blank in column 1.
Put a blank line at the end of the manifest.mf file - due to a bug in felix.
The igb, genometry and genoviz projects can by accessed as bundles.
If a class/method is needed from igb/genometry/genoviz, it must be public, and the package
must be exported in the manifest.mf Export-Package list. Ann's note: manifest.mf of what?
If you want to add a tab window (Ann's note: Do you mean panel or window, because they can be opened as new windows?) as a bundle, there is a helper abstract class, 
com.affymetrix.igb.window.service.WindowActivator, that you can extend.
If you need access to other bundles (like IGBService), you will not be sure when the
bundle is available. (Ann's note: Please explain more) For Services, like IGBService and WindowService, you can use a
ServiceTracker to be notified when the required service is available - see WindowActivator
for an example.

To create plug-ins using eclipse - a Quick-Start Guide

Eclipse (http://www.eclipse.org) makes it a lot easier to develop bundles. You can create a new project
as a plug in project, and it will give you wizards, etc. for development. see:http://www.vogella.de/articles/OSGi/article.html
(using eclipse Helios)
- check out IGB from https://genoviz.svn.sourceforge.net/svnroot/genoviz (Ann's Note: Do they need to check out the entire repository or just the trunk?)
  into a new project in eclipse
- make a new IGB_HOME environment variable to point to the IGB project (Ann's Note: What directory should it point to in the checked out code - maybe give an example?)
- open a command prompt in IGB_HOME, and do an "ant clean" and "ant jar"
- in eclipse, project explorer, right click the IGB project and select "refresh"
- in eclipse, project explorer, right click on open space, and select "Import..."
  Select "Plug-ins and Fragments" under "Plug-in Development", click the "Next >" button
     under "Import From", select "Directory:",
     under "Plug-ins and Fragments to Import" select "Select from all plug-ins and Fragments",
     under "Import As" select "Binary Projects"
     for "Directory:", click the "Browse..." button and select the IGB_HOME/ext, click the "OK" button
     click the "Next >" button
  under "Plug-ins and Fragments Found:", select affx_fusion, colt, freehep, image4j, jlfgr, picard, and sam
     click the "Add -->" button to add these all to "Plug-ins and Fragments to Import:", click the "Finish" button
- Do the following for the directories under IGB_HOME, genometryImpl, genoviz_sdk, igb, plugins/igb_service, plugins/window_service
   in eclipse, project explorer, right click on open space, and select "Import..."
   Select "Existing Projects into Workspace" under "General", click the "Next >" button
   click "Select root directory:" and click the "Browse..." button on the right
   select the project under IGB_HOME, and click "OK"
   click "Finish"

Ann's note: Please add a tutorial explaining how to develop a simple plug-in. Your graph plug-in is probably a good place to start.