TweetFollow Us on Twitter

September 93 - New Software Architectures

New Software Architectures

Jesse Feiler

Now it's Bedrock-or MFC, or Component Workshop, or Object COBOL. The choices for application frameworks are increasing, and with them, the need to formulate strategies for development and conversion of applications. New application architectures are possible-but they carry with them costs as well as benefits: new architectures may require different testing mechanisms, retraining of both developers and maintenance programmers, and rethinking of source code and documentation procedures. And, of course, new architectures carry with them a major cost-they will become old architectures and newer ones will supplant them.

The extremes of dealing with new architectures are well-known. On the one hand, there are examples of projects which quickly adopt all new architectures the moment they come out-and never finish the project. On the other, there are notorious cases of projects in which no new architectures are adopted: the code may be (grudgingly) C++, but the file structures are all based on 80-column punch cards.

Choosing an appropriate path for a specific project need not be a matter of happenstance or temperament. There are some very specific strategies to follow in deciding on adoption of new architectures.

(Note: New architectures often provide new functionalities which can directly affect the substance of an application-the TFloatWindow class in MacApp 3, for example, which replaced a number of inelegant attempts to incorporate that functionality into MacApp 2. This article does not address the issues of new architectures that can provide new benefits. We are concerned with the thornier issue of new architectures that only indirectly affect the end-user-new architectures which benefit the programmer.)

finding and identifying new architectures

It may at first seem unnecessary to think about finding new architectures-most developers' mailboxes are full of literature. The decisions about choosing implementation languages and frameworks are often made with much study and due deliberation. However, within the scope of a given framework, there are many other design decisions involving new architectures that must be made-and must be made far more frequently and with fewer resources.

Whether the project is a conversion from an earlier version of the same work or from another framework or a "from scratch" application, all of the designers, engineers, and programmers approach the work with their own bags of tricks. As part of any project design, standards are set. These standards often suggest which features of a framework will be used, and which will not. For example, we have become so convinced of the power of TBehaviors in MacApp 3 that we question any override of TView or a descendant. In almost every case the functionality that we desire can be encapsulated in a TBehavior which is attached to the TView (or descendant) in question. This solves many problems (including perennial problems with ViewEdit) and encapsulates our application-specific code in objects much smaller and less complicated than TViews.

In order to set such standards, it's important to find the new architectures. A primary source is the promotional materials about frameworks-everything from reference manuals to advertising, to presentations at MADACON, WWDC, and other groups. This material has to be carefully edited: in early presentations about MacApp 3 the gViewServer concept was stressed strongly. gViewServer is valuable, but nowhere in the league of TBehaviors.

It's also important to keep up with the literature, including reading as many code samples as possible. Unfortunately, programmers often don't like to read code, and standard computer science training provides little education in reading and evaluating code (as opposed to designing and writing it). Nevertheless, reading enough ads, code samples, and manuals (for products you use and don't use) should alert you to trends. Different frameworks may implement the trends differently, but you should be able to keep your eyes and ears alert for important, common new architectures.

One final warning: be alert for "unique selling propositions" that aren't unique. We've all been through the blood feuds of Object Pascal and C++; some people are fanning some internecine strife over Windows and Bedrock. On close examination, competing frameworks often prove to have remarkably similar functionalities. If framework X provides a unique and wonderful feature (A) and framework Y provides a more-unique and more-wonderful feature (B), at root may be some simple architecture (C)-which is implemented in framework X, Y-and framework Z.

(Author's/Editor's note: We apologize for the use of letters in the preceding paragraph. Identifying the frameworks and the particular "features" referred to could put our lives in danger.)

evaluating new architectures

What Changes Does it Require?

One of the virtues of object oriented programming is that sections of programs can easily be swapped in and out: if a new and improved object for displaying text in various scripts arises, you can removed your old object that displays text (perhaps in only one script) and plug the new one in.

Unfortunately, we are still at the point where many of the new architectures don't work that simply. We are talking about new architectures, not new objects. So a new architecture often requires modifications to a number of existing objects, and is not simply a matter of replacing one object with another. One of the best examples of this is the TDialogBehavior class in MacApp 3 (which, by the way, is a wonderful improvement!). It doesn't replace any individual object from MacApp 2. Instead, by allowing "dialog-ness" to be attached to any window, it eliminates the need for TDialogViews. The code change to truly implement TDialogBehaviors involves removing TDialogViews. The fact that a new architecture doesn't simply involve a one-for-one replacement doesn't mean that there's a problem: it simply means that you have to evaluate more issues.

In the case of TDialogBehavior, the removal of TDialogViews affects resources, and often ripples through your application, since TDialogView almost always was overridden. In a data-entry intensive MacApp 2 application, it was easy to come up with half a dozen overrides of TDialogViews. All of these classes would need to be removed, and their function-alities correctly distributed.

After evaluating the scope of the changes, you need to find something for the other side of the balance: what benefits would adoption of this architecture provide?

Does it Save Code?

We have converted a number of programs from MacApp 1.1 to MacApp 2, and others from MacApp 2 to MacApp 3. In each case (but particularly in the latter case) we have found that the converted application code was shorter than the previous version. The reason isn't hard to find. As people use the framework, many people find themselves bumping up against limits and problems. Through a forum like MacAppTech$, the development teams watch and listen. When a number of people have the same problems, a new framework or new version of an old framework is likely to incorporate not only bug fixes but framework level solutions to frequently-asked questions and common problems.

Going back to the summer of 1990, you would discover that a hot topic in FrameWorks and on MacAppTech$ was "What is My TDocument?" In MacApp 2, the TDocument was the object which contained data, which could be dirtied, which could write to a file, and which could display itself in windows. People started to have problems with documents that weren't file based (database applications) or documents that lived in several files. Lo and behold, the MacApp architecture for version 3 cut the Gordian knot of TDocument, giving us TDocuments, TFiles, TFileHandlers, and dependencies for good measure. People (like us) who had contorted databases into TDocuments found that we could make what had been a descendant of TDocument into a descendant of TObject (smaller, faster, simpler) and handle its dirtying with dependencies. Similarly, applications with multiple-file documents were able to simplify their file handling with the new structure.

In these cases, adoption of the new architectures means removing special-case code from an application and either totally on the framework for doing the task, or overriding a much smaller and more specific method of the framework. The work is pushed into the framework (good) and out of the application (good).

In the case of TDialogBehaviors, cited above, the removal of TDialogViews and their application-specific descendants also generally means a net code saving.

The virtue of saving code isn't always evident to some people. After all, we are taking something that's not broken and fixing it (TDialogViews can still be used in MacApp 3). The advantages of saving code are these:

  • Shorter compile/link cycles.
  • Easier maintenance (removing entire classes can mean removing entire files from a project).
  • Eliminating old architectures can simplify staffing requirements: there are many "horror stories" of systems that are hard to maintain because they've got one section still written in SNOBOL or PL/1.
  • Relying on a framework to provide functionality may increase the likelihood of that functionality being maintained across new system software releases. (This is a hot issue right now; in the long term, there's no doubt that this is true. Equally true is that in any given short term, it's sometimes true and sometimes not.)

What is its Life Expectancy?

Once you have evaluated the extent of the changes required to an application by the incorporation of a new architecture, and balanced them against the savings in code that can be achieved, the problem is not yet solved.

Some wonderful ideas come and go–far too soon. In evaluating an architecture's life expectancy, technical expertise seems to be less important than a knowledge of the Tarot. Yet, it's not all mysterious.

Take as an example a small office of a dozen people with a low level of computer literacy. Everyone knows Microsoft Word. On a few occasions a year, they need to incorporate pictures into documents. What would you recommend?

  1. Do it with rubber cement the way they do it now-and the way they did it in the 1950's.
  2. Buy a scanner and master Word's graphics commands.
  3. Buy a scanner and Quark.

The correct answer, of course, is A. And it's correct not because of the low volume of work, it's correct because with OpenDoc and OLE 2.0 it's reasonable to assume that the way in which graphics are incorporated into documents a year from now will differ substantially from the way in which we do it now-with any application. Now is the wrong time for a user who can afford to wait to invest in any existing application for this purpose, just as by reading the trade and financial pages you could find out that buying a color printer was probably a poor investment until this year.

Often programmers, designers and system architects look down their noses at this kind of analysis-after all, it's not technical. But, to a large extent, this type of analysis is crucial to deciding what new architectures to adopt, which to ignore, and which to watch.

A further example is that of TBehaviors. For a MacApp user who is not using TBehaviors, the decision to include them in new or existing applications might well be influenced not only by the intrinsic value of TBehaviors, but also by noting that they are present in the interfaces to a new framework.

incorporating new architectures

Laying Out the Ground Rules

Once new architectures are selected for a project, it is essential that ground rules be laid out. When we first started using TBehaviors, we used them in very limited ways. Now we have no rules about their use-save that they should be used if at all possible to avoid overrides of TView and its descendants.

TAdorners, another powerful feature of MacApp 3, also can help eliminate overrides of TView. TAdorners are a little trickier to implement than TBehaviors, because they require the under-lying views to make certain assumptions (since frame adorners are drawn within views, views which might have frame adorners added to them cannot draw to their edges in all cases).

In some cases, such as the use of the dependency mechanism in MacApp 3, the ground rules take the opposite approach. The dependency mechanism is a wonderful feature of MacApp 3, improving over the mostly idiosyncratic mechanisms that were added for each application in MacApp 2. However, the dependency mechanism can break very easily if it is not used in all cases in an application. So with regard to the dependency mechanism, our ground rule from the start has been: only the dependency mechanism can be used to communicate changes between and among objects.

Taking some time at the beginning to establish the parameters under which new architectures will be used pays off. A particular benefit is that in order to establish these parameters, it is important to truly understand the new architecture and how it relates to the known framework.

Breaking an Application

In the case of a conversion, incorporating new architectures frequently means "breaking" the existing application for a while. Replacing TDialogViews with TDialogBehaviors (or descendants thereof) can take a significant amount of time. Normally, we work with relatively small code-compile-test cycles. Breaking an application for a period of weeks runs the risk that when it is finally put back together again it won't compile for quite some time, or that when it is put back together again it won't work properly.

There is no one simple answer to this problem. One thing that can help is to compile new objects with new architectures in stand-alone applications to test their functionality. Particularly since a new architecture may be new to programmers and so be more bug-prone, this route may save time in the long run. In this strategy, instead of breaking the old application, it is simply put aside, and the new objects developed on their own. Then, when the old application is "broken" what is put in is not new code, but entire new objects which have been tested on their own.

A further help at this stage is to rely strongly on Projector (or another such tool). If the original application is "frozen" (i.e., all files checked in, read-only), the changes can be made in modifiable branches that can all be discarded if necessary to return to the status quo ante.

Testing, Documentation, and Support

New architectures challenge all members of a project team, and should be discussed and explained to everyone. Support staff who are used to fielding help calls from users "trapped" in a modal dialog need to start working-themselves-with software that features movable modal dialogs with menu access.

Many of the new architectures discussed here (TBehaviors, TAdorners, dependency mechanism, TDocument/TFileHandler/TFile structure) have the effect of moving code from the application back into the framework. Applications override smaller objects with fewer methods. Documentation procedures designed for applications with 50 overrides of TView and its descendants may need to be reviewed when those overrides all are implementations of TBehaviors.


Oddly enough, programmers are remarkably conservative. If you follow the MacApp3Tech$ traffic, you can see that people are writing programs using MacApp 2 architectures-and even earlier, non-object-oriented architectures! By picking the architectures of that will withstand the test of time, within any of the major frameworks, applications can be made as sturdy, as efficient, and as maintainable as possible.

Community Search:
MacTech Search:

Software Updates via MacUpdate

Planet Diver guide - How to survive long...
Planet Diver is an endless arcade game about diving through planets while dodging lava, killing bats, and collecting Starstuff. Here are some tips to help you go the distance. [Read more] | Read more »
KORG iDS-10 (Music)
KORG iDS-10 1.0.0 Device: iOS iPhone Category: Music Price: $9.99, Version: 1.0.0 (iTunes) Description: ** Debut Discount: 50% OFF! Sale Price US$9.99 (Regular price US$19.99). Other all Korg apps are also 50% OFF until Dec 28! **... | Read more »
World of Tanks Generals guide - Tips and...
World of Tanks Generals is a brand new card game by the developer behind the World of Tanks shooter franchise. It plays like a cross between chess and your typical card game. You have to keep in consideration where you place your tanks on the board... | Read more »
TruckSimulation 16 guide: How to succeed...
Remember those strangely enjoyable truck missions in Grand Theft Auto V whereit was a disturbing amount of fun to deliver cargo? TruckSimulation 16 is reminiscent of that, and has you play the role of a truck driver who has to deliver various... | Read more »
The best GIF making apps
Animated GIFs have exploded in popularity recently which is likely thanks to a combination of Tumblr, our shorter attention spans, and the simple fact they’re a lot of fun. [Read more] | Read more »
The best remote desktop apps for iOS
We've been sifting through the App Store to find the best ways to do computer tasks on a tablet. That gave us a thought - what if we could just do computer tasks from our tablets? Here's a list of the best remote desktop apps to help you use your... | Read more »
Warhammer 40,000: Freeblade guide - How...
Warhammer 40,000: Freebladejust launched in the App Store and it lets you live your childhood dream of blowing up and slashing a bunch of enemies as a massive, hulking Space Marine. It's not easy being a Space Marine though - and particularly if... | Read more »
Gopogo guide - How to bounce like the be...
Nitrome just launched a new game and, as to be expected, it's a lot of addictive fun. It's called Gopogo, and it challenges you to hoparound a bunch of platforms, avoiding enemies and picking up shiny stuff. It's not easy though - just like the... | Read more »
Sago Mini Superhero (Education)
Sago Mini Superhero 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: KAPOW! Jack the rabbit bursts into the sky as the Sago Mini Superhero! Fly with Jack as he lifts impossible weights,... | Read more »
Star Wars: Galaxy of Heroes guide - How...
Star Wars: Galaxy of Heroes is all about collecting heroes, powering them up, and using them together to defeat your foes. It's pretty straightforward stuff for the most part, but increasing your characters' stats can be a bit confusing because it... | Read more »

Price Scanner via

World’s First USB-C Adapter For MacBook Suppo...
Innergie, a brand of Delta Electronics, has announced its official release of the world’s first USB-C adapter supporting four DC output voltages, the PowerGear USB-C 45. This true Type C adapter... Read more
13-inch and 11-inch MacBook Airs on sale for...
B&H Photo has 13″ and 11″ MacBook Airs on sale for up to $120 off MSRP as part of their Holiday sale including free shipping plus NY sales tax only: - 11″ 1.6GHz/128GB MacBook Air: $819 $90 off... Read more
13-inch MacBook Pros on sale for up to $150 o...
Take up to $150 off MSRP on the price of a new 13″ MacBook Pro at B&H Photo today as part of their Holiday sale. Shipping is free, and B&H charges NY tax only. These prices are currently the... Read more
13-inch 128GB MacBook Air now on sale for $79...
Best Buy has just lowered their price on the 2015 13″ 1.6GHz/128GB MacBook Air to $799.99 on their online store for Cyber Monday. Choose free shipping or free local store pickup (if available). Sale... Read more
Best Buy lowers 13-inch MacBook Pro prices, n...
Best Buy has lowered prices on select 13″ MacBook Pros this afternoon. Now save up to $200 off MSRP for Cyber Monday on the following models. Choose free shipping or free local store pickup (if... Read more
Cyber Monday: Apple MacBooks on sale for up t...
Apple resellers have MacBook Pros, MacBook Airs, and MacBooks on sale for up to $250 off MSRP for Cyber Monday 2015. The following is a roundup of the lowest prices available for new models from any... Read more
Cyber Monday: Apple Watch on sale for up to $...
B&H Photo has the Apple Watch on sale for Cyber Monday for $50-$100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - Apple Watch Sport: $50 off - Apple Watch: $50-$100 off B... Read more
Cyber Monday: 15% off Apple products, and sto...
Use code CYBER15 on Cyber Monday only to take 15% on Apple products at Target, and store-wide. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-... Read more
iPad Air 2 And iPad mini Among Top Five Black...
Adobe has released its 2015 online shopping data for Black Friday and Thanksgiving Day. The five best selling electronic products on Black Friday were Samsung 4K TVs, Apple iPad Air 2, Microsoft Xbox... Read more
All-in-one PC Shipments Projected To Drop Ove...
Digitimes’ Aaron Lee and Joseph Tsai report that all-in-one (AIO) PC shipments may drop a double-digit percentage on-year in 2015 due to weaker-than-expected demand, although second-largest AIO make... Read more

Jobs Board

*Apple* New Products Tester Needed - Apple (...
…we therefore look forward to put out products to quality test for durability. Apple leads the digital music revolution with its iPods and iTunes online store, continues Read more
Software Engineer, *Apple* Watch - Apple (U...
# Software Engineer, Apple Watch Job Number: 33362459 Santa Clara Valley, Califo ia, United States Posted: Jul. 28, 2015 Weekly Hours: 40.00 **Job Summary** Join the Read more
SW Engineer - *Apple* Music - Apple (United...
# SW Engineer - Apple Music Job Number: 40899104 San Francisco, Califo ia, United States Posted: Aug. 18, 2015 Weekly Hours: 40.00 **Job Summary** Join the Android Read more
Sr Software Engineer *Apple* Pay - Apple (U...
# Sr Software Engineer Apple Pay Job Number: 44003019 Santa Clara Valley, Califo ia, United States Posted: Nov. 13, 2015 Weekly Hours: 40.00 **Job Summary** Apple Read more
*Apple* Site Security Manager - Apple (Unite...
# Apple Site Security Manager Job Number: 42975010 Culver City, Califo ia, United States Posted: Oct. 2, 2015 Weekly Hours: 40.00 **Job Summary** The Apple Site Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.