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

ExpanDrive 5.4.1 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Espionage 3.6.6 - Simple, state-of-the-a...
Espionage offers state-of-the-art encryption and plausible deniability for your confidential data. Sometimes, encrypting your data isn't enough to protect it. That's why Espionage 3 goes beyond data... Read more
Pinegrow Web Designer 2.94 - Mockup and...
Pinegrow Web Designer is desktop app that lets you mockup and design webpages faster with multi-page editing, CSS and LESS styling, and smart components for Bootstrap, Foundation, Angular JS, and... Read more
1Password 6.3.3 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Sublime Text 3126 - Sophisticated text e...
Sublime Text is a sophisticated text editor for code, markup, and prose. You'll love the slick user interface, extraordinary features, and amazing performance. Features Goto Anything. Use Goto... Read more
ForkLift 3.0 Beta 2 - Powerful file mana...
ForkLift is a powerful file manager and ferociously fast FTP client clothed in a clean and versatile UI that offers the combination of absolute simplicity and raw power expected from a well-executed... Read more
OmniFocus 2.7.1 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
CleanApp 5.1.1 - Application deinstaller...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Together 3.6.1 - Store and organize all...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Features Smart storage. With simple drag-and-drop... Read more
Cloud 4.1.1 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more

5 great apps for the budget traveller
Travelling abroad, or even within your home country, has never been easier thanks to our handy smartphone companions. There are hundreds of apps on the market that promise to make your world journeys hassle-free, but we've selected five of the... | Read more »
Zip—Zap (Games)
Zip—Zap 1.01 Device: iOS Universal Category: Games Price: $1.99, Version: 1.01 (iTunes) Description: Touch to contract.Release to let go.Bring the clumsy mechanical beings home. · · · over 100 levelsno adsno in-app-purchases Zip—... | Read more »
Paperback: The Game (Games)
Paperback: The Game 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: You are an author trying to finish kitschy paperback novels. Complete Westerns, Science Fiction, Romance or even a Crime... | Read more »
How to Rule With a Firm Hand in My Majes...
My Majesty is a kingdom management sim not unlike August’s magisterial hit, Reigns. It’s essentially a reskin of developer Tigrido’s previous management sim, Dictator. As supreme ruler of the land, you must consult with a number of subjects to... | Read more »
Our 5 Favorite iMessage Sticker Packs
At long last, iMessage joins the ranks of messaging apps the likes of LINE and Whatsapp, adding an impressive collection of stickers. They’re a great way to add a little something extra to your daily conversations. [Read more] | Read more »
How to get past Vulture Island's tr...
Vulture Island is a colorful and quirky mish-mash of platforming and puzzles. It’s creative and fresh, but sometimes the game can throw a curveball at you, leaving you stuck as to how you should progress. These tips will help you explore smoothly... | Read more »
The new Clash of Kings is just for Weste...
If you’ve played the original Clash of Kings, you’ll probably recognise the city building, alliance forging and strategic battles in Clash of Kings: The West. What sets this version apart is that it’s tailor made for a Western audience and the... | Read more »
Frost - Survival card game (Games)
Frost - Survival card game 1.12.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.12.1 (iTunes) Description: *Warning: the game will work on iPhone 5C and above and iPad Pro / 4. Other devices are not supported* | Read more »
How to build and care for your team in D...
Before you hit the trail and become a dog sledding legend, there’s actually a fair bit of prep work to be done. In Dog Sled Saga, you’re not only racing, you’re also building and caring for a team of furry friends. There’s a lot to consider—... | Read more »
How to win every race in Dog Sled Saga
If I had to guess, I’d say Dog Sled Saga is the most adorable racing game on the App Store right now. It’s a dog sled racing sim full of adorable, loyal puppies. Just look at those fluffy little tails wagging. Behind that cute, pixelated facade is... | Read more »

Price Scanner via MacPrices.net

Aetna to Transform Members’ Consumer Health E...
Health care benefits company Aetna, which has an estimated 46.3 million clients, today announced a new initiative to revolutionize members consumer health experience by combining the power of iOS... Read more
USB-IF Announces USB Audio Device Class 3.0 S...
USB Implementers Forum (USB-IF), the support organization for the advancement and adoption of USB technology, today announced the USB Audio Device Class 3.0 specification to establish USB Audio over... Read more
Clearance 12-inch 1.2GHz Retina MacBooks, App...
Apple has Certified Refurbished 2015 12″ 1.2GHz Retina MacBooks available for $1189, or $410 off original MSRP. Apple will include a standard one-year warranty with each MacBook, and shipping is free... Read more
Logitech SmartDock and Skype For Business Com...
Logitech has announced Logitech SmartDock, an AV meeting room solution designed in collaboration with Microsoft. Logitech SmartDock works with Skype for Business and qualified devices, including... Read more
27-inch iMacs on sale for up to $220 off MSRP
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $1899.99 $... Read more
Apple Macs and iPads available for up to $300...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more
Mac Pros on sale for up to $200 off MSRP
B&H Photo has Mac Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2899, $100 off MSRP - 3.5GHz 6-core Mac Pro: $3799, $... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for...
B&H Photo has the 2015 15″ 2.2GHz Retina MacBook Pro (MJLQ2LL/A) on sale for $1799, including free shipping plus NY sales tax only. Amazon also has the 2015 15″ 2.2GHz Retina MacBook Pro (... Read more
Toughbook Celebrates 20 Years of Ruggedized M...
Panasonic System Communications Company of North America, Division of Panasonic Corporation of North America (Panasonic) today celebrates the 20th anniversary of its industry-leading Toughbook mobile... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Sr. *Apple* Mac Engineer - Net2Source Inc....
…staffing, training and technology. We have following position open with our client. Sr. Apple Mac Engineer6+ Months CTH Start date : 19th Sept Travelling Job If Read more
*Apple* Retail - Multiple Positions-Norfolk,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.