TweetFollow Us on Twitter

March 93 - Reuse Abuse

Reuse Abuse

Jeff Alger and Eric Berdahle

Eric,

    Hmmm, I know it's here somewhere… aha! here on page 89 of the 1999 Sears catalog:

    Abstract Reasoning Class. Through suitable overloading and overriding, can be used to implement any reasoning process in your object-oriented program. One direct slot into which you can insert any information. Three polymorphic methods: Perceive, Cogitate, React. Defaults to no perception, no thinking, no reaction, making it useful as-is for applications such as plug-compatible movie critic replacement. Add $1.95 for next-minute shipping by electronic mail.

    C++ version:        $29.95  PN 975337-1
    Smalltalk version:  $29.95  PN 975337-2
    Lisp version:       ($ 29.95)   ('PN 975337-3)

    Sound absurd? Maybe, but the whole subject of software reuse has gotten out of hand, especially in the object-oriented community. Think about all the hype about "Software ICs," those orderable, plug-in class components of the future. Where's the evidence? What reasons are given, other than cult-like faith, for software engineering as we know it suddenly being reduced to choosing whether to buy from K-Mart or Nieman-Marcus? Have you personally ever talked to someone who has routinely achieved large-scale reuse of object-oriented software components? You wouldn't invest your kids' college fund with someone who used equally flimsy arguments for an investment scheme, and you shouldn't put any more faith in snake oil disguised as reusable ones and zeros.

    Here's the truth: object-oriented software is highly dependent on its context, and most innovative software is innovative precisely because it subtly changes the context.

    The only circumstances in which I have seen widespread reuse have been those in which the context is severely limited. For example, MacApp classes are somewhat reusable because they depend only on the Macintosh operating system, Toolbox, and user interface for context. Smalltalk even carries its context along with it through a portable kernel. This is why it is so easy to find class libraries for graphical user interfaces but not image recognition; data structures but not physical structures; reading and writing files but not parsing complex grammars. In each case, the OO community has rather sensibly gravitated toward the sorts of problems it is collectively well-equipped to solve: problems that are inherently bounded by external factors like operating systems and standards. Sensible, but limited. We cannot extrapolate from that to expect generalized reuse of Employee components from payroll to human resource management to games applications or from a Macintosh graphical user interface to a mainframe database.

    For all the talk about how "natural" the process of object-oriented analysis and design is supposed to be, we really make decisions about how to organize object-oriented programs based on artificial considerations: modularity, maintainability, extensibility, and a variety of other Itys. The process is roughly this: decide what behaviors your software needs to exhibit and what data it needs to contain, then distribute them in a modular fashion that would make your old Software Engineering professor proud. Finally, once the design has taken root, start using names that constitute good metaphors so that the design is easier to understand and explain. That Employee class is not the same as its real-world counterpart; we stole the real-world name "Employee" to leverage a basic human perceptual skill, metaphor. Change the context and the whole basis for the Itys has changed. Move most classes from one context to another and the result is poorly structured software.

    I expect reusability to grow wherever clever people can identify and clearly articulate narrow contexts and stick to them. This will take time, since it requires observing dozens or hundreds of individual cases before patterns emerge. That is where the object-oriented approach itself came from. However, most truly creative works produced by humankind involve deliberately taking things out of their original context, shuffling them together and then solving some new and outrageous problem with the combination. That's the way my kids play with their toys and I think it's true of truly leading-edge software as well. In fact, one might even hope that we don't take software ICs too seriously, since to do so is to constrain through implied contexts the very creative juices on which the industry thrives.

    A final question: who cares? I mean, about generalized software reuse? Programming as a percentage of lifecycle costs is about the size of the period at the end of this sentence and shrinking all the time. Most development costs are in planning, analysis and design, not programming, and most lifecycle costs are in maintenance, not development. If, through reuse, we reduce programming to plug-and-play, it still won't make more than a few percentage points difference in overall software costs. Reuse of analysis and design is, to me, a much more fruitful line of inquiry and one not constrained nearly as much by the peculiar technology we call OOP.

Jeff

Friend Jeff,

    I used to think that the software industry learned something from the Oat Bran Craze of the mid-80's, but recently I have come to realize that it is the other way around. Remember oat bran, the fiber health zealots proclaimed as the answer to life's greatest health mysteries? Every food product in existence found a way to work oat bran into their recipes so that, overnight, we started seeing advertisements for "Chocolate Coated Sugar Bombs-NOW with Oat Bran" as if that somehow made the most toxic food an instant nutritional success. Phooey.

    This mentality is not new to the computer industry. Every time a new language or methodology comes out, they proclaim that this solution provides better reuse than that solution, and the masses flock to the mount. Double phooey. Sure, the mythology of object software is that you get better code reuse, but let's take time to do a careful analysis and see what the reality looks like instead of blindly following the prophet.

    You make a good case for the position that object reuse is primarily due to recycled analysis. Surely, in terms of the software life cycle, analysis and design are the largest pieces of the pie. Thus, it makes sense that any attempt to make that effort recyclable will reap great benefits in terms of shortening subsequent development times. But I think you're being a little short-sighted when you casually push aside programming and development in favor of maintenance and design.

    You ask who cares? Did I fall asleep while the great Jeff Alger took a swan dive into the Twilight Zone? Surely software reuse is more than just a simple cocktail party discussion. In fact, how many developers using a good class library would claim that reuse ala class libraries does not affect time to market? Ask yourself, if you didn't use MacApp for the projects you've developed, would your time to market have been equivalent, longer, or shorter? The veterans of the object community can answer this in their sleep, indicating that there really is something to software reuse that we're not grasping here.

    Your answer to why MacApp classes are reusable is that their context is limited. While this is true, let's see what that really means. Yes, MacApp is a good abstraction of a Macintosh application, concepts that are fairly common to all applications. Yes, it is not a perfect abstraction. This is not an indictment of the concept of reuse, but of the assumptions that went into MacApp design.

    For example, remember the TDocument crisis of MacApp 2.x? In a nutshell, some developers had serious problems because TDocument had assumed that there was one file per document. Since many, but not all, applications had this model, many, but not all, applications lived happily with TDocument 2.x. This was a problem because the assumptions made by the MacApp 2.x design were violated by those multi-file per document apps, a classic case of what you yourself point out as the number one software problem: solving the wrong problem.

    In 3.x there is another problem. Sure, TFileBasedDocument is great for those developers who have 1:1 file:document mapping, but TDocument leaves a lot to be implemented those who don't. Again, this is not an indictment of reuse, but of the design. Essentially, TDocument was not provided with a full framework to support file handling. Instead, there are methods which the developer can use to tap into their own framework.

    But these examples are really edge cases. Overall, MacApp is an excellent example of the potential of object frameworks. Is it a set of software ICs? Of course not. Personally, I believe that the problem with software ICs is that the design of good object frameworks is still not understood as a general concept. Nonetheless, the examples we see each year get closer to the idyllic abstraction of the IC world.

    And what's this tripe about software ICs constraining creativity? I think that good software ICs will only enhance creativity by allowing the developer to concentrate on the very essence of their area of interest. The framework in which the IC lives should provide support all concepts outside the region of interest of the developer. This is the promise of object technology. Using MacApp examples again, MacApp provides quite a bit of support for underlying Macintosh guidelines, file system idiosyncrasies, startup hassles, and event management to name a few. While not nearly perfect, this is still the best thing we've seen yet.

    So where are we today? Reuse of object software isn't perfect, but we've already seen what its early incarnations can provide. And remember that that shrinking development time you quote may be due in large part to the effect of more and more software reuse.

    Don't worry, we'll get there someday.

Highest stirring regards,

Eric

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Sandvox 2.10.2 - Easily build eye-catchi...
Sandvox is for Mac users who want to create a professional looking website quickly and easily. With Sandvox, you don't need to be a Web genius to build a stylish, feature-rich, standards-compliant... Read more
LibreOffice 5.0.1.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
f.lux 36.1 - Adjusts the color of your d...
f.lux makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day. Ever notice how people texting at night have that eerie blue glow? Or wake... Read more
VirtualBox 5.0.2 - x86 virtualization so...
VirtualBox is a family of powerful x86 virtualization products for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers... Read more
File Juicer 4.43 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. In computer... Read more
Apple MainStage 3.2 - Live performance t...
MainStage 3 makes it easy to bring to the stage all the same instruments and effects that you love in your recording. Everything from the Sound Library and Smart Controls you're familiar with from... Read more
formZ 8.5 - Solid and surface modeler. (...
formZ pro is a powerful 3D design application featuring a variety of modeling personalities and tools with an easy to use interface to express and communicate your imagination. It is based on... Read more
PopChar 7.2 - Floating window shows avai...
We're also selling a 5-license family pack for only $25.99! PopChar helps you get the most out of your font collection. With its crystal-clear interface, PopChar provides a frustration-free way to... Read more
FileMaker Pro 14.0.2 - Powerful, easy-to...
FileMaker Pro is powerful, easy-to-use software used to create custom solutions for your business that run on iPad, iPhone, Windows, Mac and the web. Use FileMaker Pro to manage and share information... Read more
djay Pro 1.2 - Transform your Mac into a...
djay Pro provides a complete toolkit for performing DJs. Its unique modern interface is built around a sophisticated integration with iTunes and Spotify, giving you instant access to millions of... Read more

ReBoard: Revolutionary Keyboard (Utilit...
ReBoard: Revolutionary Keyboard 1.0 Device: iOS Universal Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: Do everything within the keyboard without switching apps! If you are in WhatsApp, how do you schedule a... | Read more »
Tiny Empire (Games)
Tiny Empire 1.1.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.3 (iTunes) Description: Launch cannonballs and blow tiny orcs into thousands of pieces in this intuitive fantasy-themed puzzle shooter! Embark on an... | Read more »
Astropad Mini (Productivity)
Astropad Mini 1.0 Device: iOS iPhone Category: Productivity Price: $4.99, Version: 1.0 (iTunes) Description: *** 50% off introductory price! ​*** Get the high-end experience of a Wacom tablet at a fraction of the price with Astropad... | Read more »
Emo Chorus (Music)
Emo Chorus 1.0.0 Device: iOS Universal Category: Music Price: $1.99, Version: 1.0.0 (iTunes) Description: Realistic Choir simulator ranging from simple Chorus emulation to full ensemble Choir with 128 members. ### introductory offer... | Read more »
Forest Spirit (Games)
Forest Spirit 1.0.5 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.5 (iTunes) Description: | Read more »
Ski Safari 2 (Games)
Ski Safari 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: The world's most fantastical, fun, family-friendly skiing game is back and better than ever! Play as Sven's sister Evana, share... | Read more »
Lara Croft GO (Games)
Lara Croft GO 1.0.47768 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.47768 (iTunes) Description: Lara Croft GO is a turn based puzzle-adventure set in a long-forgotten world. Explore the ruins of an ancient... | Read more »
Whispering Willows (Games)
Whispering Willows 1.23 Device: iOS Universal Category: Games Price: $4.99, Version: 1.23 (iTunes) Description: **LAUNCH SALE 50% OFF** - Whispering Willows is on sale for 50% off ($4.99) until September 9th. | Read more »
Calvino Noir (Games)
Calvino Noir 1.1 Device: iOS iPhone Category: Games Price: $3.99, Version: 1.1 (iTunes) Description: The film noir stealth game. Calvino Noir is the exploratory, sneaking adventure through the 1930s European criminal underworld.... | Read more »
Angel Sword (Games)
Angel Sword 1.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.0 (iTunes) Description: Prepare to adventure in the most epic full scale multiplayer 3D RPG for mobile! Experience amazing detailed graphics in full HD.... | Read more »

Price Scanner via MacPrices.net

12-inch 1.1GHz Gold MacBook on sale for $1149...
B&H Photo has the 12″ 1.1GHz Gold Retina MacBook on sale for $1149.99 including free shipping plus NY sales tax only. Their price is $150 off MSRP, and it’s the lowest price available for this... Read more
27-inch 3.3GHz 5K iMac on sale for $1849, sav...
Best Buy has the 27″ 3.3GHz 5K iMac on sale for $1849.99. Their price is $150 off MSRP, and it’s the lowest price available for this model. Choose free shipping or free local store pickup (if... Read more
Worldwide Tablet Shipments Expected to Declin...
Does Apple badly need a touchscreen convertible/hybrid laptop MacBook? Yes, judging from a new market forecast from the International Data Corporation (IDC) Worldwide Quarterly Tablet Tracker, which... Read more
Continued PC Shipment Shrinkage Expected Thro...
Worldwide PC shipments are expected to fall by -8.7 percent in 2015 and not stabilize until 2017, according to the latest International Data Corporation (IDC) Worldwide Quarterly PC Tracker data. The... Read more
Imminent iPhone 6s Announcement Leads To 103%...
NextWorth Solutions, with its online and in-store electronics trade-in programs including http://NextWorth.com, reports that it has experienced a 103 percent surge in quoted trade-in values over the... Read more
Weekend Deal: 13-inch Retina MacBook Pros for...
Save up to $100 on the purchase of a new 2015 13″ Retina MacBook Pro at the following resellers this weekend. Shipping is free with each model: 2.7GHz/128GB MSRP $1299 2.7GHz/... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Apple refurbished iPad Air 2s available for u...
The Apple Store has Apple Certified Refurbished iPad Air 2s available for up to $140 off the price of new models. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB... Read more
The ‘Book Mystique Still Magic After All Thes...
This column has been called The ‘Book Mystique for what has been a 15 year run so far, and I have no interest in changing the name. The reference is to what I’ve observed is a the near magical... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has 2015 15″ Retina MacBook Pros on sale for up to $184 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1815 $184 off - 15″ 2.5GHz Retina... Read more

Jobs Board

Product Design Engineer - *Apple* Watch - A...
**Job Summary** Product Design Engineer Job Description As a member of Apple 's Watch product design team, you will help to create the next generation of the world's Read more
*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
Software QA Engineer, *Apple* Pay Security...
Changing the world is all in a day039s work at Apple . If you love innovation, here039s your chance to make a career of it. You039ll work hard. But the job comes with Read more
*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
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.