Working with OSGi: The stuff you need to know

I am presenting a tutorial at EclipseCon 2010 with Paul VanderLei and Jeff McAffer that is based on the contents of our soon to be published OSGi and Equinox book.



The conference runs from Monday 22nd March until the 25th. We hear that there will be plenty of copies of the book available, so be sure to pick one up while you're there!

Safari Updated!

The manuscript for our OSGi and Equinox book has been updated on Safari. The manuscript is now in the hands of the publisher and is due to be on shelves at the start of 2010. Too late for Christmas, but not for EclipseCon.

Truth, Technology and People

I'm reading an excellent novel, which was written in 1957, that contains the following interesting quote that caught my eye:

"It is only in the realm of pure science that truth is an absolute criterion. When we deal with applied science, with technology - we deal with people. And when we deal with people, considerations other than truth enter the question."

EclipseCon 2009 Submissions

Time is short for EclipseCon 2009 submissions! All submissions must be in by 28th November, so consider submitting something now. In the meantime, check out my submissions:

• Long Talk: Best and Worst Practices for OSGi


• Tutorial: Build an OSGi Application from the Ground Up

Rough Cuts

Our first Rough Cuts edition of Equinox and OSGi: The Power Behind Eclipse is available online now!

OSGi Book in the Works

As you might have heard by now, I'm working with Jeff McAffer and Paul Vanderlei on an OSGi book. The book will be published by Addison-Wesley and will be part of the Eclipse Series. The working title is Equinox and OSGi: The Power Behind Eclipse, and you can even find it listed by Amazon, but the book won't be available until 2009.

The book is firstly an OSGi book, and secondly an Equinox book, and it covers many of the best practices that we have learned from building real-world OSGi applications. The bulk of the book is a tutorial that develops an application as you proceed through the chapters. There's also some deep dive chapters that attempt to discuss more complicated issues in detail.

We've just submitted some chapters to be published online under the Rough Cuts program, so be sure to check it out! There's also a blog dedicated to the book that we intend to update as we get closer to the publication date.

Working with Multiple LogServices

The fact that there can be multiple registered services of a particular type can sometimes be problematic. Consider the LogService and it's cousin the LogReaderService. When there are multiple registered LogService and LogReaderService pairs it can be tricky for an application to be able to present a single view of the application's logged messages.

It is this reason that SAT now has a LogReaderAggregatorService. As its name implies, it aggregates each registered LogReaderService and presents a single service API with which to work with the application's entire log. The LogReaderAggregatorService is straight forward:

public interface LogReaderAggregatorService extends LogReaderService {
  public Enumeration/*<LogEntry>*/ getLogInOrder();
  public boolean isLoggingToConsole();
  public void setLogToConsole(boolean logToConsole);
}

Since the interface extends the OSGi-defined LogReaderService you can use the API you're familiar with, such as getLog(), but of course what you'll get back is an Enumeration of every LogEvent for every registered LogReaderService, in reverse chronological order.

The LogReaderAggregatorService interfaces adds the method getLogInOrder() for accessing every logged message in chronological order, and a couple of methods for controlling whether logged messages will be echoed to the console.

While the LogReaderAggregatorService interface is part of the required bundle org.eclipse.soda.sat.core, the implementation lives in the optional bundle org.eclipse.soda.sat.core.log.