TweetFollow Us on Twitter

May 99 Factory Floor

Volume Number: 15 (1999)
Issue Number: 5
Column Tag: From The Factory Floor

Jens Alfke, AWT Engineer

by Jens Alfke and Dave Mark, ©1999 by Metrowerks, Inc., all rights reserved

This month's Factory Floor interview brings us back inside Apple for a visit with Jens Alfke, world famous creator of the Stickies desk accessory. Of particular interest this month is Jens' work reimplementing the AWT Jens' work re-implementing the AWT (Abstract Window Toolkit), the core Java user-interface framework, in the latest release of Apple's Java runtime, MRJ.

Jens Alfke, a Java Toolkit Engineer at Apple, led the effort to re-implement the AWT library in version 2.1 of Apple's Java runtime, MRJ. He has previously worked on OpenDoc and AppleScript, but is probably best known as the author of the popular Stickies desk accessory. After the demise of OpenDoc he spent a year working at a startup company and at the Java division of Sun, just to get a feel for how awkward using Windows NT on a daily basis really is. His main extracurricular technical interest is designing protocols and user interfaces for futuristic e-mail and discussion systems. In his spare time Jens plays Lego and Skwish with his two young children, saves the land of Hyrule from the evil Ganondorf with his Nintendo64, and DJs drum'n'bass and ambient music at friends' houses.

Dave: Given that Apple is a Sun Java licensee, how do you go about implementing your own version of the AWT?

Jens: There are two halves to any AWT implementation. One half, the one developers know about, consists of the public classes in the java.awt package. These define the API and much of the behavior, but they are of course incomplete because they're cross-platform and can't talk to the platform's GUI to really make anything happen onscreen.

The other half, then, is a set of platform-specific Java classes that implement the real behaviors such as creating windows, managing controls and handling events. The way the two halves connect is that some of the public classes (like Graphics) are abstract and have to be subclassed by the platform-specific AWT code, and other public classes use abstract "peer" interfaces to communicate with a set of corresponding private classes. Our AWT consists of both these concrete subclasses and implementations of the peer interfaces.

In most Java implementations the platform-specific side of the AWT is mostly written in native code - most of the private classes consists of native methods that are implemented in C or C++. But in our new AWT implementation in MRJ 2.1 we used Java wherever possible, using our JDirect feature to call the Toolbox directly and only resorting to C++ for some low level glue or for really heavily optimized graphics code. So for instance, all our code that manages controls consists of Java classes that directly call the Control Manager just as a normal Mac application would. Doing it in Java really simplified our development and resulted in cleaner code.

Dave: What was involved in rewriting the AWT?

Jens: The previous AWT implementation descended from code written at Javasoft for their old "MacJDK". It was pretty poor quality code and had to be fixed up a lot for MRJ 1.0; and it was then further hacked and extended in MRJ 1.5 and MRJ 2.0. It was clearly a codebase that needed to be thrown away and rewritten. It was also very inefficient in its graphics code, and it draw controls itself, which made it not theme-savvy.

So last May we took a deep breath and started writing a new codebase from scratch. Well, nearly from scratch - we copied over a few pieces of the old AWT (such as menu handling) and grabbed an experimental C++ library I'd written for OpenDoc that did hierarchical view management. But about 95% of the code is new.

By the time MRJ 2.1ea2 was released in August, we had an alpha-quality AWT that developers were pretty happy with. We actually kept the old AWT hidden inside ea2, with a secret switch to enable it, in case of emergency if developers ran into insurmountable problems trying to run their apps with the new AWT. But we never had to tell anyone how to enable it!

After that it was mostly a series of bug fixes and compatibility tweaks to make sure we matched every semi- or un-documented behavior of the JDK. There's no real specification for the detailed behavior of the AWT, so we had to rely on our own testing and lots of 3rd party bug reports to discover all the subtle JDK behaviors that people's code relies on, and implement them the same way in MRJ.

I started the task and did a lot of the core stuff, but the whole AWT team made it happen - Shehryar Lasi, Steve McGrath, Lee Ann Rucker, Pete Steinauer, Steve Zellers. Nick Kledzik and Nick Thompson helped out with specific features too.

Dave: These days, what are the pieces that make up the AWT?

Jens: At the lowest level there's a layer that plugs into the JManager library - that's how we receive events from the host application, and request things like windows and menus from it. Then the view system manages the hierarchy of components and containers and their clipping. There's a bunch of really complex event handling logic that maps the Mac event model into the Java event model.

Then there is our Toolkit class that acts as a factory for peers, and the component peer implementations themselves - these are where the public Java classes like Component and Button tell us what to do to make things happen onscreen. Many of these peers talk to the Control Manager, and our text peers talk to a new text editing library called Textension. Menu classes have peers too.

We have a subclass of Graphics and two subclasses of Image that implement all the abstract methods of drawing and image management. And there's a lot of miscellany for dealing with cursors, fonts and so on.

Dave: Anyone who runs the CaffeineMark benchmark knows that MRJ has made some giant strides recently. What has been done to the AWT to contribute to this?

Jens: The new AWT gives most Java components their own GrafPorts, and ensures that we never draw into the host app's window's GrafPorts. This means we don't have to spend as much time setting up and tearing down GrafPort state like clipRgns and colors, since there aren't as many different things trying to use the same GrafPorts. The new code is very lazy (in a good way!) about setting up state only when it's necessary and preserving state as long as possible.

On top of that is the graphics pipeline, which speeds up primitive drawing operations such as lines and text. These calls are written into a big array in opcode/operand style. When the array fills up, or when a split second has gone by, we make a single call to a native function that parses the opcodes and does all the QuickDraw calls. This gets around the "mixed-mode" overhead of frequent transitions between Java and native code and lets us further optimize the way we set up GrafPorts. Our raw drawing performance is now within a few percentage points of the limit of what QuickDraw can achieve.

And of course I have to give thanks to the Symantec JIT (Just-In-Time compiler) and kelly jacklin's work in integrating it - I don't think that implementing the AWT mostly in Java would have worked nearly as well without the pure speed of the new JIT.

Dave: What else changed from AWT 2.0 to 2.1?

Jens: We now use native controls - that is, we use the Control Manager for things like buttons and checkboxes. We used to draw our controls by hand; they looked awful in MRJ 1.X, looked more like real controls in MRJ 2.0, but they still weren't theme-savvy. Now with MRJ 2.1, if you change your system's appearance by installing Appearance Manager themes or Kaleidoscope schemes, the controls in Java apps will fit in. With OS 8.5 installed we also support proportional scrollbar thumbs, live scrolling and UI sound effects - in all themes.

We now use some very fast QuickTime blitters to display images.

We use a new text editing library called Textension, which will be part of the upcoming ATSUI (Apple Type Solution For Unicode Imaging.) It's a very powerful text editor, but the Java text component APIs are pretty limited, so the major benefit we get out of it is that we're no longer limited to 32k of text.

Our FileDialog implementation now uses Navigation Services if it's available.

And in general, our stability has improved, and we're a lot better at conformance with other Java implementations, so a lot of real live Java apps that were developed and tested on other platforms now run much better in MRJ.

Dave: : Tell me about Java support for Mac OS X?

Jens: OS X Server, which recently shipped, includes its own Java, which is unrelated to MRJ. The virtual machine is a straightforward port of Sun's Solaris JDK, since OS X is BSD Unix compatible. The AWT is implemented using the "Yellow Box" or OpenStep framework.

It works well, but it doesn't include the Symantec JIT, and the AWT isn't as highly tuned as the one in MRJ 2.1, so it's not as fast as MRJ 2.1 in general. It may be faster for server type applications, though, since OS X has better I/O throughput than Mac OS 8.

For the final OS X, scheduled for late this year, we'll take a hybrid approach. The virtual machine itself will be based on the current one in OS X Server. This is great, since as I said it's a straightforward port of Sun's code and therefore there will be very few compatibility issues to worry about. We'll integrate the Symantec JIT.

The AWT will be based on the one in MRJ 2.1. Actually, we're "Carbonizing" our AWT, just as a developer would Carbonize their native app, so it will run on either OS X or OS 8. That way we can keep the same codebase for both operating systems and have the same functionality on both. The Carbon strategy makes just as much sense for us as it does for, say, Adobe!

We think this will be a really great product. The Unix-based virtual machine will get us around the limitations of the current OS's threading, memory management and I/O, while the Carbon-based AWT will continue to provide very Mac-like appearance and functionality.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Bookends 12.8 - Reference management and...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
Apple iTunes 12.6 - Play Apple Music and...
Apple iTunes lets you organize and stream Apple Music, download and watch video and listen to Podcasts. It can automatically download new music, app, and book purchases across all your devices and... Read more
Default Folder X 5.1.4 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Amazon Chime 4.1.5587 - Amazon-based com...
Amazon Chime is a communications service that transforms online meetings with a secure, easy-to-use application that you can trust. Amazon Chime works seamlessly across your devices so that you can... Read more
CrossOver 16.2 - Run Windows apps on you...
CrossOver can get your Windows productivity applications and PC games up and running on your Mac quickly and easily. CrossOver runs the Windows software that you need on Mac at home, in the office,... Read more
Adobe Creative Cloud 4.0.0.185 - Access...
Adobe Creative Cloud costs $19.99/month for a single app, or $49.99/month for the entire suite. Introducing Adobe Creative Cloud desktop applications, including Adobe Photoshop CC and Illustrator CC... Read more
MegaSeg 6.0.2 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more
Bookends 12.8 - Reference management and...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
Adobe Creative Cloud 4.0.0.185 - Access...
Adobe Creative Cloud costs $19.99/month for a single app, or $49.99/month for the entire suite. Introducing Adobe Creative Cloud desktop applications, including Adobe Photoshop CC and Illustrator CC... Read more
Default Folder X 5.1.4 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more

The best new games we played this week
It's been quite the week, but now that all of that business is out of the way, it's time to hunker down with some of the excellent games that were released over the past few days. There's a fair few to help you relax in your down time or if you're... | Read more »
Orphan Black: The Game (Games)
Orphan Black: The Game 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dive into a dark and twisted puzzle-adventure that retells the pivotal events of Orphan Black. | Read more »
The Elder Scrolls: Legends is now availa...
| Read more »
Ticket to Earth beginner's guide: H...
Robot Circus launched Ticket to Earth as part of the App Store's indie games event last week. If you're not quite digging the space operatics Mass Effect: Andromeda is serving up, you'll be pleased to know that there's a surprising alternative on... | Read more »
Leap to victory in Nexx Studios new plat...
You’re always a hop, skip, and a jump away from a fiery death in Temple Jump, a new platformer-cum-endless runner from Nexx Studio. It’s out now on both iOS and Android if you’re an adventurer seeking treasure in a crumbling, pixel-laden temple. | Read more »
Failbetter Games details changes coming...
Sunless Sea, Failbetter Games' dark and gloomy sea explorer, sets sail for the iPad tomorrow. Ahead of the game's launch, Failbetter took to Twitter to discuss what will be different in the mobile version of the game. Many of the changes make... | Read more »
Splish, splash! The Pokémon GO Water Fes...
Niantic is back with a new festival for dedicated Pokémon GO collectors. The Water Festival officially kicks off today at 1 P.M. PDT and runs through March 29. Magikarp, Squirtle, Totodile, and their assorted evolved forms will be appearing at... | Read more »
Death Road to Canada (Games)
Death Road to Canada 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: Get it now at the low launch price! Price will go up a dollar every major update. Update news at the bottom of this... | Read more »
Bean's Quest Beginner's Guide:...
Bean's Quest is a new take on both the classic platformer and the endless runner, and it's free on the App Store for the time being. Instead of running constantly, you can't stop jumping. That adds a surprising new level of challenge to the game... | Read more »
How to rake in the cash in Bit City
Our last Bit City guide covered the basics. Now it's time to get into some of the more advanced techniques. In the later cities, cash flow becomes much more difficult, so you'll want to develop some strategies if you want to complete each level.... | Read more »

Price Scanner via MacPrices.net

SSD Speeder RAM Disk SSD Life Extender App Fo...
Fehraltorf, Switzerland based B-Eng has announced they are making their SSD Speeder app for macOS publicly available for purchase on their website. SSD Speeder is a RAM disk utility that prevents... Read more
iPhone Scores Highest Overall in Smartphone D...
Customer satisfaction is much higher among smartphone owners who use their device to operate other connected home services such as smart thermostats and smart appliances, according to the J.D. Power... Read more
Swipe CRM Free Photo-Centric CRM Sales DEal C...
Swipe CRM LLC has introduced Swipe CRM: Visual Sales 1.0 for iPad, an app for creating, managing, and sharing visually stunning sales deals. Swipe CRM is targeted to small-and-medium creative... Read more
13-inch 2.0GHz Apple MacBook Pros on sale for...
B&H has the non-Touch Bar 13″ 2.0GHz MacBook Pros in stock today and on sale for $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.0GHz MacBook Pro Space Gray (... Read more
15-inch Touch Bar MacBook Pros on sale for up...
B&H Photo has the new 2016 15″ Apple Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.7GHz Touch Bar... Read more
Apple’s iPhone 6s Tops Best-Selling Smartphon...
In terms of shipments, the iPhone 6s from Apple bested all competitors for sales in 2016, according to new analysis from IHS Markit, a world leader in critical information, analytics and solutions.... Read more
Logitech Rugged Combo Protective iPad Case an...
Logitech has announced its Logitech Rugged Combo, Logitech Rugged Case, and Logitech Add-on Keyboard for Rugged Case for Apple’s new, more affordable $329 9.7-inch iPad, a complete solution designed... Read more
T-Mobile To Offer iPhone 7 and iPhone 7 Plus...
T-Mobile has announced it will offer iPhone 7 and iPhone 7 Plus (PRODUCT)RED Special Edition in a vibrant red aluminum finish. The introduction of this special edition iPhone celebrates Apple’s 10... Read more
9-inch 128GB iPad Pros on sale for $50-$70 of...
B&H Photo has 9.7″ 128GB Apple WiFi iPad Pros on sale for up to $70 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 128GB WiFi iPad Pro: $649 $50... Read more
27-inch iMacs on sale for up to $200 off MSRP...
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP, each including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $... Read more

Jobs Board

*Apple* Retail - Multiple Positions- Chicago...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
Starte Dein Karriere-Abenteuer in den Hauptst...
…mehrsprachigen Teams betreust Du Kunden von bekannten globale Marken wie Apple , Mercedes, Facebook, Expedia, und vielen anderen! Funktion Du wolltest schon Read more
*Apple* macOS Systems Integration Administra...
…most exceptional support available in the industry. SCI is seeking an Junior Apple macOS systems integration administrator that will be responsible for providing Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.