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

Duet 1.6.7.0 - Use your iPad as an exter...
Duet is the first app that allows you to use your iDevice as an extra display for your Mac using the Lightning or 30-pin cable. Note: This app requires a $14.99 iOS companion app. Version 1.6.7.0:... Read more
iExplorer 4.1.5 - View and transfer file...
iExplorer is an iPhone browser for Mac lets you view the files on your iOS device. By using a drag and drop interface, you can quickly copy files and folders between your Mac and your iPhone or... Read more
Alarm Clock Pro 10.3 - $19.95
Alarm Clock Pro isn't just an ordinary alarm clock. Use it to wake you up in the morning, send and compose e-mails, remind you of appointments, randomize the iTunes selection, control an internet... Read more
Tor Browser Bundle 7.0.7 - Anonymize Web...
The Tor Browser Bundle is an easy-to-use portable package of Tor, Vidalia, Torbutton, and a Firefox fork preconfigured to work together out of the box. It contains a modified copy of Firefox that... Read more
Data Rescue 5.0.1 - Powerful hard drive...
Data Rescue’s new and improved features let you scan, search, and recover your files faster than ever before. We have modernized the file-preview capabilities, added new files types to the recovery... Read more
Alfred 3.5.1 - Quick launcher for apps a...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
Tunnelblick 3.7.3 - GUI for OpenVPN.
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
DEVONthink Pro 2.9.16 - Knowledge base,...
Save 10% with our exclusive coupon code: MACUPDATE10 DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research... Read more
AirRadar 4.0 - $9.95
With AirRadar, scanning for wireless networks is now easier and more personalized! It allows you to scan for open networks and tag them as favourites or filter them out. View detailed network... Read more
ForkLift 3.0.8 Beta - 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

Wheels of Aurelia (Games)
Wheels of Aurelia 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: | Read more »
Halcyon 6: Starbase Commander guide - ti...
Halcyon 6 is a well-loved indie RPG with stellar tactical combat and some pretty good writing, too. It's now landed on the App Store, so mobile fans, if you're itching for a good intergalactic adventure, here's your game. Being a strategy RPG, the... | Read more »
Game of Thrones: Conquest guide - how to...
Fans of base building games might be excited to know that yet another entry in the genre has materialized - Game of Thrones: Conquest. Yes, you can now join the many kingdoms of the famed book series, or create your own, as you try to conquer... | Read more »
Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »
3 reasons to play Thunder Armada - the n...
The bygone days of the Battleship board game might have past, but naval combat simulators still find an audience on mobile. Thunder Armada is Chinese developer Chyogames latest entry into the genre, drawing inspiration from the explosive exchanges... | Read more »
Experience a full 3D fantasy MMORPG, as...
Those hoping to sink their teeth into a meaty hack and slash RPG that encourages you to fight with others might want to check out EZFun’s new Eternity Guardians. Available to download for iOS and Android, Eternity Guardians is an MMORPG that lets... | Read more »
Warhammer Quest 2 (Games)
Warhammer Quest 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon adventures in the Warhammer World are back! | Read more »
4 of the best Halloween updates for mobi...
Halloween is certainly one of our favorite times for mobile game updates. Many popular titles celebrate this spooky season with fun festivities that can stretch from one week to even the whole month. As we draw closer and closer to Halloween, we'... | Read more »
Fire Rides guide - how to swing to succe...
It's another day, which means another Voodoo game has come to glue our hands to our mobile phones. Yes, it's been an especially prolific month for this particular mobile publisher, but we're certainly not complaining. Fire Rides is yet another... | Read more »

Price Scanner via MacPrices.net

Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
15″ MacBook Pros on sale for up to $200 off M...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2249, $150... Read more
Roundup of Apple Certified Refurbished iMacs,...
Apple has a full line of Certified Refurbished 2017 21″ and 27″ iMacs available starting at $1019 and ranging up to $350 off original MSRP. Apple’s one-year warranty is standard, and shipping is free... Read more
Sale! 27″ 3.8GHz 5K iMac for $2098, save $201...
Amazon has the 27″ 3.8GHz 5K iMac (MNED2LL/A) on sale today for $2098 including free shipping. Their price is $201 off MSRP, and it’s the lowest price available for this model (Apple’s $1949... Read more
Sale! 10″ Apple WiFi iPad Pros for up to $100...
B&H Photo has 10.5″ WiFi iPad Pros in stock today and on sale for $50-$100 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $... Read more
Apple iMacs on sale for up to $130 off MSRP w...
B&H Photo has 21-inch and 27-inch iMacs in stock and on sale for up to $130 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2179 $... Read more
2017 3.5GHz 6-Core Mac Pro on sale for $2799,...
B&H Photo has the 2017 3.5GHz 6-Core Mac Pro (MD878LL/A) on sale today for $2799 including free shipping plus NY & NJ sales tax only . Their price is $200 off MSRP. Read more
12″ 1.2GHz Space Gray MacBook on sale for $11...
Amazon has the 2017 12″ 1.2GHz Space Gray Retina MacBook on sale for $100 off MSRP. Shipping is free: 12″ 1.2GHz Space Gray MacBook: $1199.99 $100 off MSRP Read more

Jobs Board

Product Manager - *Apple* Pay on the *Appl...
Job Summary Apple is looking for a talented product manager to drive the expansion of Apple Pay on the Apple Online Store. This position includes a unique Read more
*Apple* Retail - Multiple Positions - Farmin...
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
Frameworks Engineer, *Apple* Watch - Apple...
Job Summary Join the team that is shaping the future of software development for Apple Watch! As a software engineer on the Apple Watch Frameworks team you will Read more
*Apple* News Product Marketing Mgr., Publish...
Job Summary The Apple News Product Marketing Manager will work closely with a cross-functional group to assist in defining and marketing new features and services. Read more
Fraud Analyst, *Apple* Advertising Platform...
Job Summary Apple Ad Platforms has an opportunity to redefine advertising on mobile devices. Apple reaches hundreds of millions of iPhone, iPod touch, and iPad Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.