Girl Writes Code

GirlWritesCode is moving to new digs; please join us.

noreply@blogger.com (Sharon) — Sun, 28 Feb 2010 13:12:00 +0000

I use Blogger's FTP model, where my posts are published out to my webhost on Invisible City. Blogger is discontinuing that service, due to lack of use and to enable bigger and better things in their architecture. So I need to shuffle things around, and I hope that you will follow this blog to its new home.

I'll update GirlWritesCode.com to redirect to the new location, so if that's the url you've bookmarked, you're good to go.

I'll continue to cross-post at Los Techies. If that's your main means of keeping up with me, then... how are you reading this? ;-)

I'll have an RSS feed from the new location, but the url is going to change. It will be http://girlwritescode.blogspot.com/atom.xml, I'm pretty sure. I'll post a "we've landed" post from the new location, so you'll know when I've got it sorted.

I appreciate your readership. Everything I write, I write with you in mind. I hope you will follow this blog to its new location.

More Dogs and Bears and Chickens and Things: Invite your colleagues to Pablo's Fiesta

noreply@blogger.com (Sharon) — Sun, 07 Feb 2010 22:32:00 +0000

If you work with developers who are women, please tell them about the Los Techies Open Space conference, coming up at the end of February. If you've attended an event like this in the past, you're already aware of some facts:

The Austin developer community is vibrant, engaged, and constantly striving to improve our craft. We've got a good thing going here.
The quality of the conversations and the value of the event far outstrip the price of admission; it would be a bargain at twice the price.
Women are way under-represented.

Early in my career, I wasn't tapped into the information channels that announce events like this. I didn't go because I just didn't know about them. My friend and colleague Josh Flanagan made a point of letting me know, and encouraging me to go, and showing that it was not only okay but right to ask my employer to send me to such things.

Attending conferences has made a huge difference in my growth as a developer and in my career. It brought me into the on-going conversation in the developer community. It exposed me to new practices and new technologies, which I brought back to the team. Please do the same favor for your women co-workers that Josh did for me: Tell them about Pablo's Fiesta and encourage them to sign up.

Bringing women into the mix brings new, diverse ideas into the conversation, new skillsets to the community, more role models for our kids. The conference will be improved by spicing up the guest list. Although I'm focusing on women here, reach out to any of your colleagues who "don't usually go to these things." New voices mean new synergy, which means more learning and more fun.

And you. Sign up, your own self. It'll be great.

If you have any questions about Pablo's Fiesta, or about whether you'd enjoy it, please feel free to post them here, and I'll get the answers for you.

Interface-Oriented Design - Book Review

noreply@blogger.com (Sharon) — Sun, 17 Jan 2010 19:04:00 +0000

Ken Pugh's Interface-Oriented Design (Pragmatic Programmers) presents an approach to designing applications that focuses first on the interfaces, the places where pieces of the application interact. The interfaces here are not primarily user interfaces, but module-to-module interfaces and service interfaces, and the applications are not exclusively object-oriented. Pugh's proposed process is to identify use cases and test cases, determine the interfaces that will enable those use cases, then create tests and implementations for the interfaces.

The book is divided into three parts. The first explains the concepts and theory underlying an interface-focused approach to design. These concepts include real-world analogies which quickly provide context to the discussion; types of interfaces, such as stateless versus stateful, and procedural versus document; design concerns such as contracts, cohesiveness, and polymorphism; and the Asimov-inspired "three laws of interfaces," which specify the qualities of a well behaved implementation. Part two is brief and describes where interface-oriented design fits into the project lifecycle. Part three walks through three examples, from concept to design to implementation, and highlights the design patterns exhibited in those examples. The book concludes with a grab-bag appendix of topics that could have been better served by integration into the main text.

If your learning style is learn-by-doing, you might get more out of the book by reading Part Three before Part One. Part Three provides the "yeah, but what are we doin' here" skeleton onto which you can hang the theory that is explained in Part One. I find theory easier to digest and retain if I know which of my real-world, day-to-day experiences it applies to. You'll get that context if you flip the order in which you read it.

I picked up this book looking for best practices on providing and consuming remote interfaces, and it isn't that. Have you ever taken a sip of something you like, but because you were expecting a completely different flavor, it tasted off? I bumped into that dissonance here, so it was hard for me to get into the book. To appropriately prepare your palate, the flavor to anticipate from Interface-Oriented Design is a technique for thinking about a problem domain and its software solution by thinking about the places where responsibilities interact, analogous to the way that service-oriented architecture is a technique for thinking about software design.

An area where this book really shines is Pugh's deft use of real-world examples. In the first chapter, he introduces the process of ordering a pizza as a series of exchanges through a PizzaOrdering interface. The example is familiar, relatable, and practically identical across the United States (implementations vary, of course). Pugh then uses that example and expands upon it throughout the rest of the book, allowing us to fit new concepts into the model as it is refined. This worked better than if each new concept had been presented with a new example; the book gained a pedagogical momentum.

Many times during my reading, I asked myself whether the ideas were so fundamental and distilled as to shift my way of thinking, or so fundamental as to be mundane and trivial. Was this book raising the level of abstraction, like climbing a mountain to get a better view of the landscape, or just telling me no-duh stuff I already knew? Is its audience experienced developers looking to put terms and practices around habits they do instinctively, or is its audience beginners who need an introduction to methodical design? I still haven't decided. Will it affect my thinking? Probably. Not in ways that I can articulate and enumerate for you, but likely in subtle and profound ways that I may or may not notice as they occur. For yourself, I recommend checking out the table of contents (available from the Pragmatic Bookshelf) and see if it suits you.

Happy Hack-o-ween: Electronics and a microcontroller spice up the haunt

noreply@blogger.com (Sharon) — Sun, 08 Nov 2009 16:35:00 +0000

Ah, Halloween, when a young woman's fancy turns to love. And zombies.

I had two personal requirements for the costume I would build this year:

It shall be spooky.
It shall blink.

I'll tell you about the final result, the electronics and the software that went into it, plus the techniques I used to achieve wearable electronics. I'll introduce you to the Arduino, an open-source microcontroller prototyping platform, which is an exhilarating tool/toy for making your software skills manifest in the physical world.

My husband and I have been teaching ourselves electronics. A few months ago, Dad taught me to solder. I recently read Syuzi Pakhchyan's excellent primer on wearable electronics and smart materials, Fashioning Technology. And I've been making things with my Arduino. All these ideas were swirling and combining in my head to inspire this year's Halloween project. Er, costume. Same difference.

What was I? I was a nightmare... the thing under your bed... the reason for your well developed sense of paranoia...

I sported a crop of writhing eyeballs erupting from my head. Each eyeball has an LED inside it, and they blink randomly and independently, until I trigger a hidden switch, which causes the blinky ones to go dark and two red eyes to pulse menacingly. In the Flickr photoset, you can see the construction process.

The Arduino Sketch

The term "Arduino" is overloaded to mean:

a particular chip and circuit board which you can buy or build;
the IDE in which you write programs for the chip;
the language, which is C-flavored;
fun.

Arduino programs are called sketches. Every sketch must contain two functions: setup (runs once) and loop (runs continuously). Here's my sketch, with extra explanatory comments, that blinks the six regular eyeballs and responds to the switch by pulsing the red eyeballs.

    1 #define SWITCH 8

    2 int ledPins[] = {2, 3, 4, 5, 6, 7};

    3 const int ledPinsCount = 6;

    4 int redEyePins[] = {10, 11};

    5 const int redEyePinsCount = 2;

    6 long durations[ledPinsCount];

    7 int ledStates[ledPinsCount];

    8 long previousTimes[ledPinsCount];

    9 int i;

   11 void setup()

   12 {

   13   pinMode(SWITCH, INPUT); //Specify the switch pin as an input.

   15   for (i = 0; i < redEyePinsCount; i++)

   16   {

   17     pinMode(redEyePins[i], OUTPUT); //Specify each red-eye LED pin as an output.

   18   }

   20   for(i = 0; i < ledPinsCount; i++)

   21   {

   22     pinMode(ledPins[i], OUTPUT); //Specify each regular LED pin as an output.

   23     ledStates[i] = random(1); //Randomly set the LEDs to on or off (1 or 0).

   24     durations[i] = GetRandomDuration(); //Define a random duration for each LED to stay in that state.

   25     previousTimes[i] = 0; //At time of setup, the "last time we changed" is at 0 milliseconds, the start of time.

   26   }

   27 }

   29 void loop()

   30 {

   31   if (digitalRead(SWITCH) == HIGH)

   32   {

   33     TurnOffLeds();

   34     PulseRedEyes();

   35   }

   36   else

   37   {

   38     for(i = 0; i < redEyePinsCount; i++)

   39     {

   40       digitalWrite(redEyePins[i], LOW); //Turn the red eyes all the way off.

   41     }

   43     for(i = 0; i < ledPinsCount; i++) //For each LED:

   44     {

   45       if (millis() - previousTimes[i] > durations[i])

   46       {

   47         ChangeLed(i); //If this one's duration is up, then flip it.

   48       }

   49     }

   50   }

   51 }

   53 void TurnOffLeds()

   54 {

   55   for(i = 0; i < ledPinsCount; i++)

   56   {

   57     digitalWrite(ledPins[i], LOW);

   58   }

   59 }

   61 void PulseRedEyes()

   62 {

   63   //Fade on, then off.

   64   int j;

   65   for(j = 0; j < 255; j+=5)

   66   {

   67     for(i = 0; i < redEyePinsCount; i++)

   68     {

   69       analogWrite(redEyePins[i], j);

   70       delay(10);

   71     }

   72   }

   73   for(j = 255; j > 0; j-=5)

   74   {

   75     for(i = 0; i < redEyePinsCount; i++)

   76     {

   77       analogWrite(redEyePins[i], j);

   78       delay(10);

   79     }

   80   }

   81 }

   83 void ChangeLed(int ledPin)

   84 {

   85   previousTimes[ledPin] = millis(); //Update the "last time we changed" to now.

   86   durations[ledPin] = GetRandomDuration(); //Give it a new random duration.

   87   ledStates[ledPin] = 1 - ledStates[ledPin]; //Flip the state between on and off.

   88   digitalWrite(ledPins[ledPin], ledStates[ledPin]); //Set the LED to that state.

   89 }

   91 long GetRandomDuration()

   92 {

   93   //Random number between 1 and 10, then multiplied by 400 to give it a detectable duration.

   94   return random(1, 10) * 400;

   95 }

I like the way the eyes blink independently. If they all flashed in unison, they would look like Christmas lights, and you would notice that two were "special" because they weren't flashing. Instead, the duration that any given eyeball is lit or dark constantly changes.

The blinking is managed by a collection of arrays. One array represents each of my LED pins, so that I can address them in a for loop. The three other arrays hold: the state (on/off) of each LED; the duration each LED should stay in that state; the reading from the millisecond counter when the LED last flipped its state. Each time the loop function executes, if the switch is not connected, then I look at each LED; if the difference between the current time and the time when it previously changed is greater than its duration, flip its state (from off to on, or from on to off), randomly assign it a new duration, and record "now" as the new "previously changed" time. If the switch is connected, then I make the red eyes fade on and fade off.

Fading with PWM

PWM (Pulse-Width Modulation) is a technique for making a digital component (one that turns on or off) simulate analog behavior (be a little bit on, and then a little bit more on). If you turn an LED off and on really quickly, you won't perceive the flickering, but it will look half as bright, because it is actually off for half the time. If you let it spend a little more time off than on, it will appear even dimmer. So by varying the width of the pulses, you can control how bright the LED looks.

The Arduino comes with built-in PWM functions; some pins are already set up to be PWM pins. If you plug an LED into one of the PWM pins, then you can write to it as if it were an analog component. That's why, in my sketch above, I set the brightness of the red eyes using analogWrite(), instead of digitalWrite(). My for loop increments the counter j from 0 to 255, and sets the brightness of both red eyes to the value of j. The Arduino takes care of (imperceptibly) flickering the LEDs with the right ratio of on-time and off-time to achieve a j amount of brightness. So the eyes get gradually brighter, then gradually dimmer. (Then control returns to the main loop function, but if my switch is still connected, the red eyes will throb again.)

Snaps: Wearable Plugs

A metal sewable snap is like a plug for your clothing, an interface between the world of textiles and the world of wires. This is handy when you need the electronics to be separate while you are getting into the clothing, or if you want to wash the clothing. My Arduino hung out at the base of my neck, to be near the LEDs on my head but hidden underneath my wig, but my control switch was near my hip. I could have run a wire down to the switch, but conductive thread was more subtle and more comfortable.

To complete the connection, I soldered a short wire to one side of the snap. That wire plugged into a pin on the Arduino. The conductive thread ran from the switch at my hip up to the back of my dress near the Arduino, and I sewed that conductive thread to the other half of the snap. When the two halves are snapped together, the wire and the thread make a complete connection, as if they were one continuous wire.

I had two threads (going out to the switch and back), so I encased them each in a bias tape tube, to prevent them from touching each other and shorting out.

I've been saying "switch," but actually, I simplified at the 11th hour. I tied each thread around a safety pin, and stuck the pins to my dress. When the safety pins touched each other, they completed the circuit, which the Arduino sketch interpreted as triggering the switch—cue red-eye glare.

What's Next

Soldering and sewing are both liberating skills to possess—they free up your creativity to make wilder and more integrated stuff. If you are currently proficient with only one, ask around and see if you can find a buddy who's good at the other, and teach each other.

The Arduino comes with a great community of hackers and makers, lots of people to learn from and collaborate with. Definitely check it out. There is lots of fun to be had, and blinking LEDs is the barest beginning of what it can do.

Refactoring Dinner: Interfaces instead of Inheritance

noreply@blogger.com (Sharon) — Wed, 14 Oct 2009 02:24:00 +0000

Last time, in Cooking Up a Good Template Method, I had a template method cooking our dinner. An abstract base class defined the template—the high level steps for preparing a one-skillet dinner—and a derived class provided the implementation for those steps. I'm currently reading Ken Pugh's Interface Oriented Design (more on that after I finish the book), and it got me thinking of a way to change the design to use interfaces instead of inheritance.

I think there's value in this refactoring because it allows future flexibility and testability. Let's stroll through it, and I welcome your thoughts about how (and whether) this improves the code.

Previously, we had a base class SkilletDinner, which was extended by variants on that theme, such as chicken with onions and bell peppers or the FancyBaconPankoDinner. (If I've learned one thing from my readership, it is that blog posts should mention bacon. Mm, crispy bacon.) As the first step in the refactoring, I'll create an interface, ISkilletCookable that provides the same methods that were previously abstract methods in SkilletDinner. By naming convention, the interface is prefixed with 'I' and is an adjective describing how it can be used (-able).

    4   public interface ISkilletCookable

    5   {

    6     void HeatFat();

    7     void SauteSavoryRoot();

    8     void SauteProtein();

    9     void SauteVegetables();

   10     void AddSauceAndGarnish();

   11   }

Next, I'll create a SkilletDinner constructor that accepts an ISkilletCookable, and change the SkilletDinner's Cook() method to ask that cookable to do the work. SkilletDinner no longer needs to be abstract.

    5   public class SkilletDinner

    6   {

    7     private readonly ISkilletCookable cookable;

    9     public SkilletDinner(ISkilletCookable cookable)

   10     {

   11       this.cookable = cookable;

   12     }

   14     public void Cook()

   15     {

   16       cookable.HeatFat();

   17       cookable.SauteSavoryRoot();

   18       cookable.SauteProtein();

   19       cookable.SauteVegetables();

   20       cookable.AddSauceAndGarnish();

   21     }

   22   }

Then, FancyBaconPankoDinner implements ISkilletCookable and provides implementations for each of the methods that will be called by the Cook() method.

The first benefit from this refactoring is flexibility. While FancyBaconPankoDinner could not have inherited multiple classes (no multiple inheritance in C#), it can implement multiple interfaces. For example, it could also implement the IShoppable interface, thereby providing a ListIngredients() method that would let me include it in my grocery list.

This refactoring also makes it easier for me to test the quality and completeness of my template method. I can verify—does it cover all of the requisite steps for cooking a skillet dinner?—by creating behavior-verifying tests that assess the SkilletDinner's interactions with the ISkilletCookable interface. When I'm writing unit tests for the SkilletDinner class, I want to test its behavior because the behavior is what's important.

To forestall objections, I tried writing a test around the old version, creating my own mock class that extends the old abstract SkilletDinner. It got pretty lengthy.

    4   public class SkilletDinnerSpecs

    5   {

    6     [TestFixture]

    7     public class When_told_to_cook

    8     {

    9       const string heatFatMethod = "HeatFat";

   10       const string sauteSavoryRootMethod = "SauteSavoryRoot";

   11       const string sauteProteinMethod = "SauteProtein";

   12       const string sauteVegetablesMethod = "SauteVegetables";

   13       const string addFinishingTouchesMethod = "AddFinishingTouches";

   15       [Test]

   16       public void Should_follow_dinner_preparation_steps_in_order()

   17       {

   18         var systemUnderTest = new MockSkilletDinner();

   20         var expectedMethodCalls = new List<string>();

   21         expectedMethodCalls.Add(heatFatMethod);

   22         expectedMethodCalls.Add(sauteSavoryRootMethod);

   23         expectedMethodCalls.Add(sauteProteinMethod);

   24         expectedMethodCalls.Add(sauteVegetablesMethod);

   25         expectedMethodCalls.Add(addFinishingTouchesMethod);

   27         systemUnderTest.Cook();

   29         Assert.AreEqual(expectedMethodCalls.Count, systemUnderTest.CalledMethods.Count, "Expected number of called methods did not equal actual.");

   31         for (int i = 0; i < expectedMethodCalls.Count; i++)

   32         {

   33           Assert.AreEqual(expectedMethodCalls[i], systemUnderTest.CalledMethods[i]);

   34         }

   35       }

   37       private class MockSkilletDinner : SkilletDinner

   38       {

   39         public readonly List<string> CalledMethods = new List<string>();

   41         protected override void HeatFat()

   42         {

   43           CalledMethods.Add(heatFatMethod);

   44         }

   46         protected override void SauteSavoryRoot()

   47         {

   48           CalledMethods.Add(sauteSavoryRootMethod);

   49         }

   51         protected override void SauteProtein()

   52         {

   53           CalledMethods.Add(sauteProteinMethod);

   54         }

   56         protected override void SauteVegetables()

   57         {

   58           CalledMethods.Add(sauteVegetablesMethod);

   59         }

   61         protected override void AddFinishingTouches()

   62         {

   63           CalledMethods.Add(addFinishingTouchesMethod);

   64         }

   65       }

   66     }

   67   }

In the new design, I can mock the ISkilletCookable interface with a mocking framework like Rhino.Mocks. The interface is easy to mock because interfaces, being the epitome of abstractions, readily lend themselves to being replaced by faked implementations. Rhino.Mocks takes care of recording and verifying which methods were called.

    7   public class SkilletDinnerSpecs

    8   {

    9     [TestFixture]

   10     public class When_told_to_cook

   11     {

   12       [Test]

   13       public void Should_follow_dinner_preparation_steps_in_order()

   14       {

   15         var mocks = new MockRepository();

   16         var cookable = mocks.StrictMock<ISkilletCookable>();

   17         var systemUnderTest = new SkilletDinner(cookable);

   19         using (mocks.Record())

   20         {

   21           using (mocks.Ordered())

   22           {

   23             cookable.HeatFat();

   24             cookable.SauteSavoryRoot();

   25             cookable.SauteProtein();

   26             cookable.SauteVegetables();

   27             cookable.AddSauceAndGarnish();

   28           }

   29         }

   30         using (mocks.Playback())

   31         {

   32           systemUnderTest.Cook();

   33         }

   34       }

   35     }

   36   }

The test relies on Rhino.Mocks to create a mock implementation of ISkilletCookable, and then verifies that the system under test, the SkilletDinner, interacts correctly with ISkilletCookable by telling it what steps to do in what order.

That test is quite cognizant of the inner workings of the SkilletDinner.Cook() method, but that's specifically what I'm unit testing: Does the template method do the right steps? I don't mind how the steps are done, but you have to start the onions before you add the meat, or else the onions won't caramelize and flavor the oil.

By the way, if you had previously found the learning curve for Rhino.Mocks' record/playback model too steep a hill to climb (or to convince your teammates to climb), check out Rhino.Mocks 3.5's arrange-act-assert style. It creates more readable tests, putting statements in a more intuitive order. I really like it. I could not, however, use it here because I have not found a way to enforce ordering of the expectations (i.e., to assert that method A was called before B, and to fail if B was called before A) in A-A-A-style. So we have a record/playback test, instead.

Here's a summary of the refactoring. I extracted an interface, ISkilletCookable, and composed SkilletDinner with an instance of that interface, liberating us from class inheritance. Because SkilletDinner is now given the worker it depends on (via dependency injection), I can give it a fake worker in my tests, so that my unit tests don't need to perform the time- and resource-consuming operation of firing up the stove. And I managed to write another blog post that mentions bacon. Mm, bacon.

Cooking Up a Good Template Method

noreply@blogger.com (Sharon) — Sat, 29 Aug 2009 17:18:00 +0000

The software concept of "raising the level of abstraction" has improved my skill and creativity in cooking, by teaching me to think about recipe components in terms of their properties and functions. Practicing abstraction-raising in cooking feeds back to help me with coding; for example, keeping me from going astray the other day with the Template Method pattern. This post is more about coding than cooking. The cooking's a metaphor. (The cake is a lie.)

Abstract Cooking
My skill with cooking grew from rote recipe following to intuitive creation when I started to think of it in terms borrowed from software: raising the level of abstraction.

Consider a week-night skillet dinner. If I told you to heat canola oil in a cast-iron skillet, saute slices of onion and chunks of chicken seasoned with salt and pepper, and toss in bell peppers cut into strips, you could probably follow along and make exactly that. But that's pretty limiting. If instead I described the process as using a fat to conduct heat for sauteing a savory root, a seasoned protein, and some vegetables, then you could use that as a template, and make a week of dinners without repeating yourself.

Let's dive into that step of using a fat for conduction, because it is a cool and useful bit of food science. To cook, you need to get heat onto food. The medium can be air, liquid, or fat. Each creates different results, hence the terms baking, boiling, and frying. When you toss cut-up bits of food in a skillet with oil and repeatedly jostle them, you're sauteing ("saute" means "to jump"), and that oil is playing the role of the fat, which is conducting the heat. If you'll pardon the metaphor, CanolaOil implements the IFat interface.

It's useful to think of cooking this way, because if you know the properties of the various cooking fats, you can choose the right IFat implementation for the job. Canola oil is heart-healthy and stands up well to stove-top heat. Olive oil has wonderful health benefits, a bold flavor, and an intriguing green color, but those attributes are pretty much obliterated by heat, so save your expensive EVOO for raw applications like salads and dips. Butter makes everything taste better, browns up beautifully, but is harder on the heart and will burn at a low temperature; temper it with an oil like canola to keep it from burning. Peanut oil stands up to heat like a champ, so it's popular for deep frying. Armed with this kind of knowledge, I don't need to check a recipe when I'm cooking; I just think about what I'm trying to accomplish, and choose the right implementation.

Pam Anderson's How to Cook Without a Book got me thinking about food this way, and Harold McGee's On Food and Cooking provides a feast of food geekery to fill in all the particulars.

Template Coding
Thinking about food this way, raising the level of abstraction, guides my thinking about code. My meal preparation follows the Template Method pattern, as does a class my teammate and I needed to modify recently.

In this example, our application sends instructions to various external systems. The specifics of how those systems like to hold their conversations vary between systems. However, the series of steps, when phrased in our core business terms, remain the same. You do A, then you do B, then you do C, in whatever way a particular instance likes to do A, B, and C.

Here's my class with its template method, translated back to the dinner metaphor:

    3     public abstract class SkilletDinner
    4     {
    5         public void Cook()
    6         {
    7             HeatFat();
    8             SauteSavoryRoot();
    9             SauteProtein();
   10             SauteVegetables();
   11         }
   12 
   13         protected abstract void HeatFat();
   14         protected abstract void SauteSavoryRoot();
   15         protected abstract void SauteProtein();
   16         protected abstract void SauteVegetables();
   17     }

But lo, I encountered an external system that needed to do one extra little thing. I needed a special step, just for that one instance. Like dinner the other night, where the vegetable was asparagus, the fat was bacon (oh ho!), and the final step was to toss some panko breadcrumbs into the pan to brown and toast and soak up the bacony love.

How do I extend my template method to accommodate an instance-specific step?

One idea that floated by was to make the method virtual, so that we could override it in our special instance. But we still wanted the rest of the steps, so we'd have to copy the whole method into the new instance, just to add a few lines. Also, anybody else could override that template, too, so that when they were told to do A, B, and C, they could totally fib and do nothing of the sort.

    3     public abstract class SkilletDinner
    4     {
    5         public virtual void Cook()
    6         {
    7             //Note: The Cook template method is now virtual,
    8             //and can be overridden in deriving classes. 
    9             //That's not good.
   10             HeatFat();
   11             SauteSavoryRoot();
   12             SauteProtein();
   13             SauteVegetables();
   14         }
   15         protected abstract void HeatFat();
   16         protected abstract void SauteSavoryRoot();
   17         protected abstract void SauteProtein();
   18         protected abstract void SauteVegetables();
   19     }
   20 
   21     public class LazyDinner : SkilletDinner
   22     {
   23         public override void Cook()
   24         {
   25             OrderPizza();
   26             //We're overriding the template and *cheating*!
   27             //Although, if it's Austin's Pizza, 
   28             //maybe that's okay...
   29         }
   30 
   31         private void OrderPizza()
   32         {
   33             //With extra garlic!
   34         }
   35 
   36         protected override void HeatFat() { }
   37         protected override void SauteSavoryRoot() { }
   38         protected override void SauteProtein() { }
   39         protected override void SauteVegetables() { }
   40     }

That LazyDinner class isn't really a SkilletDinner at all; its behavior is completely different. No, that option flouts the whole point of the Template Method pattern.

Our better idea was to make one small change to the template method, adding an extension point. That is, a call to a virtual method which in the base implementation does nothing, and can be overridden and told to do stuff in specific cases.

Back to dinner:

    3     public abstract class SkilletDinner
    4     {
    5         public void Cook()
    6         {
    7             HeatFat();
    8             SauteSavoryRoot();
    9             SauteProtein();
   10             SauteVegetables();
   11             AddFinishingTouches(); //Here's the hook.
   12         }
   13 
   14         protected virtual void AddFinishingTouches()
   15         {
   16             //By default, do nothing.
   17         }
   18 
   19         protected abstract void HeatFat();
   20         protected abstract void SauteSavoryRoot();
   21         protected abstract void SauteProtein();
   22         protected abstract void SauteVegetables();
   23     }
   24 
   25     public class FancyBaconPankoDinner : SkilletDinner
   26     {
   27         protected override void AddFinishingTouches()
   28         {
   29             //In this case, override this extensibility hook:
   30             ToastBreadcrumbs();
   31         }
   32 
   33         private void ToastBreadcrumbs()
   34         {
   35             //Toss in the bacon fat; keep 'em moving.
   36         }
   37 
   38         protected override void HeatFat()
   39         {
   40             //Cook bacon, set aside, drain off some fat.
   41         }
   42 
   43         protected override void SauteSavoryRoot()
   44         {
   45             //Minced garlic, until soft but before browning
   46         }
   47 
   48         protected override void SauteProtein()
   49         {
   50             //How about... tofu that tastes like bacon?
   51         }
   52 
   53         protected override void SauteVegetables()
   54         {
   55             //Asparagus, cut into sections. 
   56             //Make it bright green and a little crispy.
   57         }
   58     }

This maintains the contract of the template method, while allowing for special cases. With the right extensibility hooks in place, my dinner preparation happily follows the Open-Closed Principle�open for extension, but closed for modification.

I enjoy the way my various hobbies feed into and reflect upon each other. I hope this post has given you some useful insight into the Template Method pattern, or dinner preparation, or both. Look for synergies amongst your own varied interests; it can be the springboard for some truly breakthrough ideas.

Mmm, bacon...

Inconvenient Accessibility Makes Self-Documenting Code

noreply@blogger.com (Sharon) — Sat, 20 Jun 2009 12:19:00 +0000

Intentional use of access modifiers (public, private, etc.) is like a clear memo to your team. This came up during Steve Bohlen's Virtual Alt.Net talk on domain-driven design.

Steve explained the distinction between Entity objects, which have a unique identity independent of their properties (Even when I change my name, I'm still me.), and Value objects, which are defined by their properties (If you change the house number in an address, you have a new address.). When dealing with Entities, code should not be able to change the unique id—that would be like someone claiming your social security number and thereby becoming you. Therefore, Entity classes should have private setters for their unique identifiers.

A meeting attendee asked why, since this gets inconvenient when you're creating an object based on a record fetched from the persistence repository. It's a big pain; why bother? The analogy I would offer is this. When you're defining a class to represent an Entity in your business domain, you know it's an Entity. You intend for it to behave and be treated like an Entity. You don't want any of your teammates setting its unique id in their code. So you send them an email: "Don't set Person.UniqueId, okay?" Uh hunh. How well is that going to work over time?

Instead, if you simply don't provide a public accessor to the UniqueId property, your teammates will get the message loud and clear. Granted, someone could edit the code and change the accessibility, but the fact that he or she needs to is a flashing neon sign saying "Stop. Think. Are you barking up the wrong tree?" You've made your code communicative. Its structure conveys your intent. No need for comments; this is an example of self-documenting code.

Giving Mono to my Husband

noreply@blogger.com (Sharon) — Sun, 31 May 2009 20:37:00 +0000

Holy crossed-platforms, Batman! How did I not know about Mono, the free, open-source framework that will run .NET applications on Linux and Mac OS X?

Not to get too personal, but I'm part of a mixed marriage: I run Windows and develop primarily in C#; my husband runs OS X and is not (actively) a programmer. Through love and mutual respect, we make it work. But what we have so far not been able to make work is my writing handy utilities and toys that he can use on his laptop.

I learned about Mono in Rod Paddock's intro to the May/June issue of CoDe Magazine. Then I came home, had Jon install Mono on his Mac, and gave him a quick little console app I'd written in C#. It ran like a charm. A WinForms app with one button and a popup message also ran, looking distinctly X11-y.

This is super exciting for us. We've been talking about a card-game playtest simulator, to help with his creation of card games. (Jon posts one free board game a month and has a few upcoming commercial releases.) That process usually involves a significant investment in card stock and time with the paper cutter, just to see how hands of cards come together and move through the game. A simulator would help him to vet the first and maybe second drafts of the cards without printing them out. Now that I know I can build something he'll be easily able to run, it's time to start designing!

Got the 0000FFs

noreply@blogger.com (Sharon) — Sat, 25 Apr 2009 16:08:00 +0000

Given up on attaching meaning to those three- or six-character codes that define colors in HTML and CSS? Sure, you can use an online color picker, but let me give you a nuts-and-bolts explanation of what they mean. This info is worth having because:

It's a time-saver. If you want to make a color a little more blue, or a little less saturated, you can do the math in your head and take care of it right there in your editor.
It gives you more options. If you find a cracking color combo in the Color Index, but it's given only in RGB values, you can convert it to HTML-ready values using just math.
It's satisfying. Don't you prefer knowing how something works, instead of just how to work with it?
It will be diverting. There will be stories, you know me.

Two experiences in my childhood laid the foundation for my understanding of hex color codes, so I will share them with you. (See? Stories.)

When I was very young, I learned that the three primary colors are red, yellow, and blue, and when you mixed them together you got, well, mud, but theoretically black. That's true for pigments (paint and ink; think magazines and newspapers), and if you're going to be pedantic, those pigment primary colors are properly called magenta, yellow, and cyan. (Add blacK and you have CMYK, the other color scheme you'll see mentioned in design books.) But it's a whole 'nother ball game when you are mixing light instead of pigment, and computer monitors are big light bulbs.

My seventh-grade science teacher, Mr. Saeger, created an excellent demonstration that I still think of when I'm mixing up hex color codes. He set up the overhead projector. He placed a square of red cellophane on the projector, and it threw a red square of color up on the wall. Sure. Then he added a piece of green cellophane, and the area where they overlapped was... yellow? That's curious. Last he added a piece of blue, and the intersection of all three was white. It blew my mind.

If you can replicate this effect (shine a light through overlapping colored plastics), it's a great science experiment to share with your kids. It will help you remember the mixing of light colors with the same intuition you have for mixing pigments. And it's cool.

The second formative experience from my youth was working the stage lights in my high school theater. Hanging above the stage were three rows of lights; the lights alternated amongst white, yellow, red, and blue, and were controlled by a huge wall of levers backstage. Big, creaky, ancient things, that really let you know you were working the lights. I had to crouch and get my shoulder under them to move the big ones.

Picture them: Four rows of colored levers, corresponding to each color of light out over the stage. Each lever controlled a light. Down was off, and as you pushed the lever up, the light would gradually brighten. A big handle at the end of a row would move all the levers of that color, so you could, for example, bring up all the whites in unison. You could slowly turn down the yellows over the course of a scene while a teammate pushed up the reds, and make a sunset. You could push all the colors up to make the light full and cheery (and make the stage hotter than a tanning booth), or pull them all down to plunge the stage into darkness at the dramatic conclusion of Act I.

Levers... lights... hex codes, here we go.

Light is mixed from red, green, and blue. (Remember the order: RGB, RGB, RGB.) Computers like to count not from 1 to 100, but from 0 to 255. Think of 0 as off, with the lever all the way down, and 255 as on, with the lever all the way up. To make yellow, you need a lot of red and a lot of green, and no blue, so R = 255, G = 255, and B = 0. To make a paler yellow, you want to bring it closer to white. White is all three on at maximum; therefore you need to turn up the blue. Maybe R = 255, G = 255, and B = 153. To make it more orangey, you'd back off the green. And so forth.

So we have three levers. A hex color code has three pairs of characters. That yellow would be #FFFF00. Put another way: FF, FF, 00. It's the same three RGB values, but in base 16 instead of base 10. 255 in base 10 becomes FF in base 16. Counting in base 16 is like counting in base 10, if you had 6 extra fingers. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10.

The Math Bits site gives a visual explanation of how to convert from base 10 to other bases. Also, you can use the calculator on your computer. In Windows, set the calculator to Scientific mode in the View menu, make sure the "Dec" radio button is marked, type in your base-10 number, then switch to the "Hex" radio button and read the converted value. But usually when I'm writing HTML, I just need to nudge a color a little, not do a whole decimal-to-hexadecimal conversion. So it is sufficient to know that all zeroes is all black, all Fs is all white, CC is more "on" than 99, and EE is just a teeny bit less than full on.

CSS also permits three-character color codes. The same color-mixing is happening there, it's just a shortcut that doubles each character for you. So #ca9 is equivalent to #CCAA99.

Putting this into practice...

#FFFFFF	Turning all three levers full on makes white.
#CCCCCC	Backing them off a little, but keeping them all equal, makes gray.
#000000	Turning them all off: Black.
#FF0000	Red on and the rest off makes red.
#990000	Turning down the red, so that it moves closer to black, makes a darker red.
#FF6666	Turning up the others, so that the whole mix moves closer to white but has more red than anything else, makes pink ("Lightish red!").
#FFFF00	Red plus green (when mixing light) make yellow.
#FF9900	Keep the red, but reduce the green, to make orange.
#00FFFF	Green and blue make teal.
#FF00FF	Red and blue make purple.

So there you have it: An explanation of hex color codes by way of my seventh-grade science class and my high school drama—er, drama department. Right.

The Null Object Pattern: When a slacker is just what you need

noreply@blogger.com (Sharon) — Tue, 03 Mar 2009 00:35:00 +0000

I had a challenge that was neatly solved by the Null Object pattern. I'd like to share it with you, so that I can explore the idea and provide a practical example.

Simplifying a bit, I have a Person object, and I need to fill it with details retrieved from an external system. When I started looking at the code, the call to look up the Person attributes took a Person as a passed-in parameter and modified it. That struck me as bad behavior ("Hey! I gave you that so you could use it, but I didn't expect you to change it. Sheesh."). I thought it would be more honest for the method to return information, which the controlling class could use to update the Person object if it chose to.

Let me name the players, to make this easier to follow. I have a class coordinating activities that, in our business context, is called a Translator. I created a Client that makes the actual calls to the external system. Before the refactoring, the Translator would call Client.Lookup(Person). The Client would create a message to the external system, get back a response, and use it to set attributes in the Person.

I changed Client.Lookup so that it does not change the Person, and instead returns a Response that contains the needed attributes. But if the external system did not have any info to return, should Lookup return null, throw an exception, ...?

Usually the most appropriate answer to this question is to throw an exception. If no info means you're in an invalid state or an unknown state, then it is not safe to continue, and the code should throw. In this case, though, we could continue. We didn't require the info coming back from the external system; it was just handy if available.

So I return null? But that means every time I call Client.Lookup, I have to check whether the Response is null before I use it. And so does anyone else who might be calling it in the future. It seems disingenuous for a method to say, "I'll give you a Response, but I might actually give you an empty bag. I hope you've guessed I might do that and planned accordingly."

   12 public void DoFancyBusinessSteps(Person person)
   13 {
   14     Response response = client.Lookup(person);
   15     if (response != null)
   16     {
   17         person.Address = response.Address;
   18         person.ExternalSystemId = response.ExternalSystemId;
   19     }
   20     //More stuff based on the Person...
   21 }

I'd rather return an object that is safe to use, regardless of what answer we got from the external system, and is helpful if we received useful info. This is the Null Object pattern.

I created an IResponse interface that exposes one method, Update(Person). Next I created two implementations of that interface, a Response and a NoDataResponse.

   12 public void DoFancyBusinessSteps(Person person)
   13 {
   14     IResponse response = client.Lookup(person);
   15     response.Update(person);
   16 
   17     //More stuff based on the Person...
   18 }

Response.Update uses its fields to set properties on the Person (with a method name that clearly states it is doing so). NoDataResponse.Update quietly does nothing. This allows the Translator to ask the Client to look up info about the Person, and ask the resulting Response to update the Person.

   21 public class NoDataResponse : IResponse
   22 {
   23     public void Update(Person person)
   24     {
   25     }
   26 }

I like it. As with all good tools, it's prudent not to over-use it. If quietly doing nothing would leave the Person object in a bad state, so that it blew up or corrupted data when you tried to use it later, then don't use the Null Object pattern. Throw an exception instead. The Null Object pattern is handy when you want to return an object that can do stuff in some conditions and will be harmless in other conditions.

Follow-up to the Retrospectives Workshop

noreply@blogger.com (Sharon) — Tue, 24 Feb 2009 22:59:00 +0000

My co-facilitator Suzy wrote up her reflections from the AgileAustin retrospectives workshop, where she shares more of the great insights that came from the participants.

Retrospectives: Collaborative Improvement

noreply@blogger.com (Sharon) — Sat, 21 Feb 2009 23:08:00 +0000

Suzy Bates and I facilitated an AgileAustin workshop this morning called "Cheaper Than an Off-Site: How to hold effective retrospectives that improve team collaboration and performance." It was absolutely a blast, from planning through delivery. A benefit I didn't anticipate (but should have) is that I learned a lot, myself. I'll share some of those epiphanies here.

If you were to ask me what one thing a team could do to improve its delivery of great software on a predictable schedule, I would say: hold effective retrospectives. A retrospective is a regularly recurring discussion where the team reflects on how they work together, and what they will change in order to get better. The end of a sprint, right after the demo, is a good time for this.

We presented the following as the key ideas:

Safety
Diversity of viewpoints
Collective ownership
Structured discussion

Being a facilitator for the workshop was a bunch of fun. Collaborating with Suzy was excellent—meshing our two approaches really enhanced the content, as I brought the philosophy and she brought the practical hands-on exercises, and we kept each other moving and making progress on our preparations. If you're tempted to lead a workshop but daunted, find a teammate.

The audience participation was even richer than I'd hoped. People enthusiastically contributed, leapt into the exercises with gusto, and shared some striking insights. I learned neat stuff. Here are some highlights:

Rotate who holds the role of retrospective leader (or sponsor). That brings fresh ideas and spreads the sense of shared ownership.

When a team member expresses dissatisfaction (for example, through a team satisfaction histogram), sometimes it is appropriate to acknowledge it without delving into why and root cause and solutions. If team safety means I can say how I feel and that's okay, then I should be able to say how I feel without getting interrogated about why I feel that way.

A bunch of "went well" items without any "needs fixing" items might indicate a lack of team safety. In today's exercise, our sprint teams barely knew each other, so they wanted to be polite, and so they were very positive in their reflections. When you're comfortable with your team and trust them, it becomes easier to talk about areas for improvement. I'd view a series of "everything was great" sessions as indicative of a lurking problem.

Affirmative Inquiry is a philosophy/strategy worth looking into. It replaces, for example, the negative "why is this broken" by changing it into a positive "what was successful in the past that we could apply here."

Book recommendation for Jim Highsmith's work (probably Agile Project Management?).

If you attended the workshop: Thanks! It rocked. If you weren't able to, keep an eye out for future AgileAustin workshops. They're announced on the AgileAustin email list, so sign up for that. If you don't live in Austin, well... nanny nanny boo boo.

Quantifying Benefits on Refactoring Work

noreply@blogger.com (Sharon) — Sun, 11 Jan 2009 19:05:00 +0000

When last we talked about estimating and prioritizing code maintenance, we'd left it as an exercise for the reader to devise a method to compare the relative size of the benefit from two different refactorings. In other words, you can work on A or B; which one is likely to give a greater benefit? I've had an idea for how to do this. It even includes some satisfying math.

Start with the premise that, when estimating the size of effort, it is sufficient—nay, preferable—to compare values in an abstract unit ("story points") that does not map directly to any real-world concept (such as "hours"). When you try to estimate effort in a real-world unit, people get distracted by (hung up on) the wrong details. Better to use an abstract unit that lets you compare the relative sizes of two efforts. Then you can prioritize them ("Let's do the smaller one."), and over time you develop a predictive measure of how many units your team can deliver. Can we create a similarly abstract yet useful unit for comparing benefits?

You undertake a refactoring because you want to make the code better. The benefit from this work comprises two pieces: how much you're going to improve an area of the codebase, and how important that area is. Your impact will be made up of how much "betterness" you can impart, and how much the betterness will matter.

You've probably had a similar experience: You find an area of the code that makes you frankly itch to improve it. You could dramatically increase its beauty. But it's not really used in very many places, and business needs hardly ever drive you to change it, so its beauty or lack thereof is actually rather insignificant. On the other hand, there's a class that makes you queasy every time you have to interact with it, but it's used everywhere, so changing it would be a huge, risky undertaking. It stays ugly, despite being so important.

There are a number of intuitive and emotional influences in those decisions, and they interact with each other in additive and multiplicative ways. This is a good place to apply some rigor, to get the emotions out of the way and compare options more objectively. You apply a similar rigor when you tackle a difficult decision by actually writing down the pros and cons in two columns on a piece of paper, so that you can see how the two sides stack up. So let's apply that to comparing the possible benefits from two refactorings. We only have time to do one, so we're trying to decide which one to do.

Consider a questionnaire, with pairs of questions, asking about what the code might be like after you're done.

Future proofing:

How much easier will it be to change it the next time?

How often do we get asked to change this area?

Regression proofing:

How much better will our test suite be able to prevent defects in this area?

How business-critical is it that we don't introduce defects in this area?

Avoiding risk:

How likely are we to succeed without creating problems?

How tolerant is our business of risk in this area?

Improving satisfaction and increasing velocity:

How likely are we to reduce tech support incidents by this work?

How many of our tech support incidents can be attributed to this area?

And so on, with questions that are specific to your own team. Collaborate with your team to create the questions, so that they represent the team's decisions. Note how a pair of questions covers how much improvement and how much that improvement will matter. Also see that for each question, a more emphatic answer is a good thing. For example, the avoiding-risk question asks how likely we are to succeed, not how risky the task is. Questions are phrased so that, the more you say "Yes, a lot," the more that's an endorsement in favor.

Now, depending on your bent, this next bit will remind you either of a prioritization matrix or a Cosmo quiz. Nevertheless, for each question in your questionnaire, answer a 1, 3, or 5, to represent "barely," "some," "a lot." Then multiply the coordinated a's and b's and add those up: (1a * 1b) + (2a * 2b) + (3a * 3b)... In this way, you represent the multiplicative relationship between How Much Better and How Much Does It Matter.

We need a unit for these scores. I'm thinking "bunits" (BYOO-nits) because they are a unit of benefit and of beauty. So if you have two refactoring tasks on the table during your sprint planning, and Refactoring A has an effort of 13 story points and a benefit of 17 bunits, while Refactoring B has an effort of 8 story points and 23 bunits, you can lean towards choosing Refactoring B. As with all matrices of this type, if that decision completely flouts your intuition, then discuss it with your team—maybe your intuition can be calmed, or maybe the questionnaire is failing to cover an important aspect of your work and needs some additional questions.

The real benefit of refactoring is proven only over time. Keep previous bunit estimates in mind and use those in your comparisons and trade-offs when selecting refactorings to undertake. Add this technique as another tool to help you understand the parameters of your decision, but never to override your own good sense.

This is a technique for quantifying the benefit of work that does not have a direct dollar ROI. Why quantify benefit, especially in a unit that has no analog in the real world? Two reasons. First, if you're going to prioritize your to-do list, every item needs some sense of effort and some sense of reward. It just makes sense to do easy things with lots of benefit before hard things that barely matter. Second, asking yourself questions like the above imparts rigor to your decision-making process. We are seekers of beauty, and want desperately to clean up whatever icky thing we looked at most recently. Surveying the choices and comparing relative benefits prods us to make sound business decisions, instead of scratching an itch.

The Trouble with Technical Debt

noreply@blogger.com (Sharon) — Sun, 09 Nov 2008 20:09:00 +0000

This article is not about the perils of accumulating technical debt, nor the challenges in paying it down. Instead, it is a call to action to the developer community that we change the way we talk about scheduling technical debt.

It's a constant sore spot and the source of many arguments between developers and product owners: How do you make time for refactoring? When do you pay down your technical debt? I say we developers need to change how we make our proposals.

We ask our product owners to prioritize the backlog: to attach a business value to each user story and put them in order. Then we provide a size estimate for each story, indicating its relative cost in time and resources, and voilà: a prioritized list of requirements with a cost and a benefit for each.

Then we propose investing some time in cleaning up a lurking problem. The work will improve our velocity in the future. By how much? A lot. And how long will it take? A while. So please fit this chunk of work into your carefully prioritized backlog.

You see what we have here, folks: an ArgumentNullException. The product owner has sorted a list of objects based on their cost and their benefit, and then we try to place an object into the list with an undefined cost and an undefined benefit. No amount of arguing is going to make that work.

The first counter-argument I receive from folks is that the business should trust us or, from the more progressive thinkers, that we need to earn the trust of the business. Um, perhaps. But imagine you were the person prioritizing your own list. Even if you trusted your own motives perfectly, how would you prioritize an item with unknown cost and unknown benefit amongst a list of items with known costs and benefits? And that's assuming perfect trust; I'm skeptical of our discipline to admit that substandard, icky code can be good enough. Developers (the good ones, anyway) have a strong desire for elegance and simplicity.

The second counter-approach I hear is timeboxing: allocate a fixed amount of time to refactoring and only spend that much time. That fills in a value in the "cost" column, but it does not address the undefined benefit. Also, can you think of a scenario where you've undertaken a significant refactoring, the clock ticks over, but you're not yet in a stable state? You either roll back the changes (and realize zero benefit), or muscle through (increasing the cost)? For the timeboxing approach to honestly reflect your cost, you must work with the discipline to make many small, beneficial changes, and stop when the clock runs out. Are you up for that?

Speaking of size, be sure to consider the testing cost. Technical debt accumulates in the areas folks are afraid to change. Those are usually business-important, application-spanning areas. Your refactoring will likely touch many features in the application, warranting thorough regression testing. How good is your automated test suite? Be responsible about how much testing you'll need, and be honest about how much time it will take.

Okay, agile developer community. If we're going to get technical debt work and refactoring into a sprint, we need to apply the same rigor that we ask from our product owners. Cut the work into a discrete unit. Write acceptance criteria so you'll know when you've finished. Make some kind of estimate of the benefit; talk with your teammates about how you might quantify such benefit. Using the acceptance criteria, estimate the complexity and size, same as if the work had been requested by your product owner. Observe and reflect on the predictive accuracy of your cost and benefit estimates to improve your estimates in the future. Start conservative to build experience and credibility over time.

Most product owners are happy to invest time in making the product more stable and making the team faster on future features. We need to give them estimated costs and estimated benefits so they can fit that work amongst other business priorities.

Organizing Ideas with Concept Maps

noreply@blogger.com (Sharon) — Sun, 02 Nov 2008 12:58:00 +0000

I love concept maps as a way of explaining a topic. (Here's an example, capturing what I learned at a KaizenConf session.) If you're a visual thinker, you'll definitely want to check this out. If you design UIs, this is also of interest.

The way I use concept maps most often is exploring and explaining a concept to myself. The act of drawing the map sorts my ideas visually, lets me hang new information off logical hooks, and gives me a picture to visualize when I want to recall the info later. (If you've talked with me about F# and watched where I gestured, you've seen that OO ended up on the left side of my map, and functional programming was right of center.)

CmapTools is a free software application that makes drawing maps intuitively easy—better than paper, because you can move concepts after you've fleshed out more of the landscape. And I have a strong preference for paper for brainstorming and thought-capturing, so that's saying something.

I like it not only as a tool, but also as an example of usability. It's so low-friction because you trigger actions (creating a concept, making a connection) right where you're already focused, in the work area, not in some menu at the top of the window. Click-and-drag from an existing concept to create a new concept and connect them; then type, click, type to enter the labels on the connection and the concept. I admire CmapTools for its non-noisy GUI—and of course I love it as a user because I can create a map fast enough to not lose the thread of my thoughts.

The example linked above is cool in another way: It's on a wiki where participants at KaizenConf are creating the conference proceedings. Once you go self-organizing, baby, you'll never look back.

Oh, I needed that.

noreply@blogger.com (Sharon) — Sun, 02 Nov 2008 02:38:00 +0000

So the thing about mind-expanding, discussion-rich conferences is they can leave you feeling a little overwhelmed with how much more you have yet to learn. At the end of the day, I wanted a cup of tea. The aphorism-inscribed flag on my teabag said:

"Keep up."

Sprint Heartbeat: Visual Task Tracking

noreply@blogger.com (Sharon) — Tue, 30 Sep 2008 00:50:00 +0000

Continuing to think about visually tracking the health of a sprint, I advocate tracking at the task level, rather than the story level. Recall that my goals for a successful solution include:

Radiate information.
Clearly communicate whether the sprint is on track and likely to conclude successfully.
Alert us to lurking risks, so that the team can react and adapt proactively.
Tell a story about the sprint from which we can learn during our retrospective.

Instead of moving user stories through phases (development, review, testing...), list their tasks. Tasks for a story could include testing and reviewing pieces, merging code into previous versions, meeting with a product owner to review the UI and clarify requirements, or convening a design session. You can add tasks to the list as they are discovered, which can signal that a story is ballooning or that a technical problem is thornier than originally estimated. If there are certain steps the team is trying to get more rigorous about (like writing unit tests before writing code), you can list them as explicit tasks until they become second nature.

Each day, estimate the number of hours remaining in each task. Not the hours spent, and not a comparison of estimates to actuals. This is not about "metricking estimation accuracy" or some other useless bean counting; it is about ascertaining right now, today, how many hours' worth of work is there left to do, and will that fit in the time we have left.

The hours remaining on a task might go up. (Ever peel back the wainscoting on a piece of code and find it's all termites underneath?) New tasks might get added during the sprint. The reason to track the hours remaining is so that you can adjust when you spot a potential problem—perhaps a team member is getting pulled away with other work, or is stuck in a mess of code that your expertise could alleviate, or maybe it's time to negotiate a trade-off with your product owner. To deal with any of these effectively, you need to know, if you'll pardon the vernacular: Where we at?

In the sample task list above, you can see that we're not only showing the hours remaining, but also tracking the movement of that number day after day. That allows us to make a graph, creating that visual heartbeat we're looking for.

At the end of the day (or completion of a task), update tomorrow�s column for the number of hours remaining for that task. If you finish a task on Day 4, then at the start of Day 5, there are zero hours remaining for that task. New tasks that crop up unexpectedly should show a zero until the day on which they were discovered, and then an hours-remaining estimate until finished.

The graph plots each day's sum of estimated hours remaining. It also shows an idealized burndown line, as if the team were completing [original hours estimate / number of days] worth of work each day. This makes the picture clearly communicate whether you're in fair weather or potential trouble.

If estimating hours remaining seems daunting, split the tasks into smaller pieces. A task should fit within a day, and the work you claim in the morning stand-up should fit within a day.

Time tracking is a sensitive topic, and suggesting it may not be well received by the team. Despite good intentions, many organizations use time accounting policies abusively. Superstitious beliefs, uncharacteristic vehemence, and irrational resistance are indicators of prior abuse. There is a tension between the two Agile tenants of transparency and self-organizing teams: I don�t want to hide data from you, but if I let you see the tools we�re using to track our progress, you�re liable to interfere, draw wrong conclusions, or base bonuses and promotions on them. These are not flaws in tracking sprint progress, though; they are deeper organizational issues, that are worth correcting and rehabilitating so that the team can take advantage of a burndown chart's benefits.

A graph tracking your team's completion of work gives you a picture of the state of the sprint, making it easy to see if you're on track to succeed, and alerting you to struggles early enough to react.

Visible Sprint Status: Maybe Not Corkboards?

noreply@blogger.com (Sharon) — Sun, 21 Sep 2008 19:25:00 +0000

I'm thinking about ways to track the activity—the status... progress... stuff—that happens within a development sprint.

You could conceive a user story as moving through a series of phases (e.g., development, code review, testing, accepted). You might set up your Scrum task board using this paradigm, where you move an actual piece of paper between different columns on a corkboard. Some project-management software packages I've evaluated encourage a workflow of phases.

I wonder if there's a better way. At the user-story level, the idea of "passing through phases" seems Waterfall-ish, which always snags my attention because so few human endeavors are that linear. Phases lead you into some non-Agile patterns of thought, and they obfuscate the current health of the sprint.

Mike Cohn's task boards (with pictures!) divide into rows as well as columns. A row corresponds to a user story, and the tasks that compose that story move through the columns, which correspond to statuses. I'd previously missed (or forgotten) this distinction, and I thought the cards on the board were stories. I finally noticed the difference while drafting up this blog post, because I went looking for corroboration about the disadvantages of moving user stories through phases on your task board. What follows is an analysis of those disadvantages: non-Agile patterns and obfuscated sprint status.

By non-Agile patterns, I mean that columns on a board draw boundaries (literal and metaphorical) between collaborators. Do you intend to tell your testers that they can't think about a story until it lands in their column? Are you keeping your product owner from looking at a feature until all the code is built and blessed (and you've run out of time in the sprint)? Are you throwing code over the wall at people who might as well be in a different department?

"Heck no!" you cry. But doesn't a task board with indivisible user stories, sitting inertly in discrete statuses, imply that's what you're doing? Well, it could. And the metaphor subtly seeps into your thoughts and behavior, constraining your team's responsiveness, creativity, and collaboration.

How does a story-oriented task board obfuscate the status of your sprint? After all, it is tangible, visible, large-as-life where everybody can see it. But what is it telling you? Here are some challenges I've observed.

The pieces of paper representing user stories are the same physical size, but the effort required for different stories can vary dramatically. You glance at the board for a gut check, but you'll draw the wrong conclusion from lots of little stories (unnecessary worry) or few big stories (misplaced complacency). You could ameliorate this by making the pieces of paper represent component tasks instead of whole stories, but does a mere task move into the testing phase? Does your product owner evaluate a task? Can your customers use one? No, they need complete user stories. Once you've made the papers represent similar-sized chunks of work, the moving-through-phases metaphor gets in the way again.

Phases are liable to proliferate, until you want more columns than is practical for an actual corkboard. For any given phase, you might want to distinguish between "Ready to be picked up" and "In progress." Even if you're tracking virtually in a project-management tool, having too many phases is still annoying; you spend your time clicking dropdown lists instead of creating software. If you're in this mode, though, one solution for distinguishing between "ready" and "in-progress" is to write your name (or set the "Assigned To" field) on an item when you claim it.

Some items visit a phase more than once—like when a tester discovers a bug and gives the story back to a developer. (See that hand-off? That's the non-Agile-ness rearing its head again.) So when you see an item in the development column, is that its first trip through, meaning a lot of work remains, or a subsequent trip and it's nearly finished? You can't tell by looking at the board.

A communicative tracking tool would show you where bottlenecks or wasteful idleness is occurring. Using phases obfuscates this as well, because it implies that your testers aren't even looking at a user story until the coding is complete. (Can you call a piece of coding complete if it hasn't been tested or shown to the product owner? I'd say not. So read "complete" as a different word that represents "passed from the Development phase to the Testing phase.") But testers at the beginning of a sprint are creating test plans and collaborating with developers and product owners on the acceptance criteria; their "Testing" column looks empty, but they are in fact very busy with useful work. Someone outside the team might look at the board, conclude that the testers are idle, and be tempted to distract them with other tasks.

What a list. It's strange to me to write it. At my old job, my team had to have a virtual task list so that we could share it across continents. I was always jealous of the kids who got to have real live note cards on real live corkboards. Oh, how wistful I was, to have such an elegantly simple solution.

But now that I've used a task board, I can see its limitations, and I wonder about alternatives. I still want to cling to the belief that a tangible solution is better than a software tool, but I might have to let that go. Software is much better, for example, at turning points of information into a communicative picture. It is also better at searching, archiving, sharing with out-of-town stakeholders, and scaling.

The right solution will radiate information. It will clearly communicate whether the sprint is on track and likely to conclude successfully. It will alert you to lurking risks, so that the team can react and adapt proactively. It will tell a story about the sprint from which you can learn during your retrospective. These are the requirements by which I'm evaluating tracking techniques. The right method will show the heartbeat of the sprint.

You're too kind. Tip yer waitress.

noreply@blogger.com (Sharon) — Thu, 04 Sep 2008 00:48:00 +0000

There's a "Pho King Coming Soon" sign near my house, which means there will soon be another Pho King restaurant. I wonder what their Pho King food will be like. I hope they have good Pho King service, and a nice Pho King ambiance.

Oh, why get excited? It's just Pho King noodles.

Yes, Jon and I can amuse ourselves for miles with this gag.

Market Research

noreply@blogger.com (Sharon) — Wed, 02 Jul 2008 03:11:00 +0000

Your opinion, please: What are the qualities of a conference that attracts a sparkling diversity of attendees?

I'd like to gather our collective observations and apply them to increasing the variety of ideas that are brought to our conferences and the variety of people we reach with our ideas. My first practical applications will be software-oriented conferences, but I think the best suggestions may come from non-software events. Think broadly; where have you been amongst a bunch of people who differ from you, where you benefited, learned, and taught?

The question usually comes to me regarding women, but I'm interested in other kinds of diversity, too:

interaction style
culture
experience level
type of experience
project methodology preference
age
outlook
interests
worries
...

So please, think about gatherings you've attended where a lot of different people harmoniously shared and challenged ideas. What gave those gatherings the opportunity to bring those people together? Once they were there, what made the space safe for them to contribute, to speak up, to risk being different?

If you don't mind, ask this question around. I'm looking for a bunch of contributions that are, well, diverse.

Workstation Hack: Visual Studio on 2 monitors

noreply@blogger.com (Sharon) — Thu, 26 Jun 2008 21:28:00 +0000

Having two monitors is an obvious improvement to any development workstation, but are there tricks for really effectively using all that extra acreage? I learned a great strategy from a co-worker for a two-monitor setup for Microsoft Visual Studio.

Hack Summary
Maximize the editor on one screen, and pull out all the floating windows (Solution Explorer, Error List, etc.) onto the second screen—which is great until you want to look at your database or your wiki or your work-in-progress app while also typing code. (If you're typing in the editor, Visual Studio is in front, which means all those little windows are in front of any other app you want to look at while coding.) The solution is to set up some shortcut keys that switch you from "Sprawl across two screens" mode to "Pull everything into one screen, dock the little windows, and make the second monitor available for other stuff" mode, and back.

Export Two Sets of Window Settings
You can save Visual Studio settings (such as window layout) to a file, and later import that settings file. For this hack, we'll export two settings files (one for two-screen, sprawl mode; one for one-screen, compact mode). Then, we can switch from one mode to the other by importing the appropriate settings file.

Get your windows how you like them in one-screen mode. For example, my Solution Explorer is a docked pane on the right, unpinned so that it auto-hides; and so on, for the handy windows I want at my fingertips. So, set those up.

Go to Tools > Import and Export Settings... > select the radio button for Export > click Next > uncheck All Settings > expand General Settings > check Window Layouts > click Next. Name the file (e.g., OneScreen.vssettings) and give it a location. Click Finish.

Now set up your windows in two-screen mode. Unhide a window by hovering over it, pin it, right-click on its title bar, and pick Floating. Drag it where you want. This is the artistic phase.

As above, export those settings, with a different name (e.g., TwoScreens.vssettings).

Create Two Switcher Macros
Add a macro module in the Macros IDE (Tools > Macros > Macros IDE), and create two macros, one to import each settings file. Here's my module, called WindowsSettingsSwitcher, which gets my settings files from C:\VSSettings\.

Imports System.IO
Imports EnvDTE
Imports EnvDTE80
Imports System.Diagnostics

Public Module WindowsSettingsSwitcher
    Public Sub SwitchToWinLayoutTwoScreens()
        DTE.ExecuteCommand("Tools.ImportandExportSettings", "-import:C:\VSSettings\TwoScreens.vssettings")
    End Sub

    Public Sub SwitchToWinLayoutOneScreen()
        DTE.ExecuteCommand("Tools.ImportandExportSettings", "-import:C:\VSSettings\OneScreen.vssettings")
    End Sub
End Module

You can test the macros from the Macro Explorer by double-clicking their names.

Assign Shortcut Keys to the Macros
Create some shortcuts that execute those macros. Tools > Options > expand Environment > click Keyboard. In the "Show commands containing" box, enter some text that will find your macros, e.g., "switchtowin" if you used my names above. Highlight a macro, put your cursor in the "Press shortcut keys" box, and type your shortcut. (Mine are Ctrl+Alt+1 for one-screen, and Ctrl+Alt+2 for two-screen, since those weren't in use by anything else.) I left the "Use new shortcut in" set to "Global." Click OK.

At this point, you can use your shortcut keys to switch modes. I added them to my View menu, too, mostly to give me a visual reminder of the shortcuts.

Add Switcher Commands to the View Menu
Tools > Customize > Commands tab > select the "Macros" category. Click and drag your macro from the Commands list in the dialog up to your toolbar. When you hover over View, the View menu will appear, showing the insertion point for your new command. Drop it in place. Right-click on the command in its new location, click on the Name box, and edit that down to something helpful (e.g., "OneScreen"). Repeat to add the other macro. Close the Customize dialog.

With this hack, you can keep lots of useful Visual Studio bits visible (liberating you from relying on the mouse to hover over auto-hiding windows, and maximizing your editor window), but stow them away quickly when you need the second screen for something else.

So how 'bout you? What are your workstation hacks?

Change your organization, or...

noreply@blogger.com (Sharon) — Thu, 12 Jun 2008 12:40:00 +0000

So here's the thing about being in a place that makes you depressed: You're too depressed to make the changes necessary to get out of the place. It can seem insurmountable. In eerily coincidental-sounding but utterly unrelated news (*cough*), I have a new job! You will certainly already know this if you've had occasion to see me bouncing off the walls lately. While some of my friends are content in their jobs, many are not, so I'll share my self-help program, in the hopes that it might console and inspire those who are wishing for a change.

I had been in the old job for 8 years, so even thinking about a change was scary. Here's what I did.

Believe.
You deserve a job that makes you happy.

Really, you do. You probably have a list of reasons why you need to stay at the place you're at, but look critically at those reasons. Put yourself into a five-year-old's mindset and ask "Why? �Why? �Why?" about each one. The reasons on my list, when I started doing some fact-checking out in the real world, turned out to be myths.

Throw rocks at that old adage, "�that's why they call it 'work.'" Pfft, whatever. If you're reading my blog, I'll assume you're a knowledge worker, and probably a programmer, and someone who likes to think about new ways of doing things. Lucky us, there are many lucrative careers for people who like to think. For me, writing software is like play—heck, it is something I do for play—so I didn't need to find a different line of work, just a different job that let me write software. You don't need to suffer to put bread on your table.

Network.
Get out there, walk amongst the people. If you're really sunk in the doldrums, this is probably the most tempting one to blow off, but here are some benefits: meet people with similar interests and challenges; dispel myths about the job market; find inspiration, in people who like their jobs, in people with passion; meet job prospects; become known for your ideas and contributions.

Networking and professional venues I find helpful: door64, AgileAustin, AgileATX, GeekAustin, Austin .NET User Group, classes, and my blog. Yeah, yeah, and LinkedIn.

Define the goal.
I developed a really clear list about what I wanted in an employer. Honed it, you might say. Took it out during meetings and quietly polished it. But this was helpful, because it gave me a concise list of interview questions to ask of my potential employers. The ultimate filter question, the one at the top of the list that immediately let me know whether it was even worth continuing, goes like this: "Do you like your job?"

Look for a yes. There are a ton of answers that are not yeses. I know, because I had years of delivering them myself. "It presents me with a lot of challenges. I get to work with people from all over the world, and I'm part of a great team." Yeah, but that wasn't a yes. I want to work in a place where it's possible to like your job.

Keep it positive.
No matter how bad it is, if you come off as a complainer, you will sour job prospects. Be diplomatic, and steer the conversation to what you're working towards, what you look for in the future.

Seek support.
To keep the gushing to a minimum, I'll simply say: My husband rocks. You've probably got someone, too, whether a sweetie or a best friend, a pen pal or your mom or your dog, someone who knows that you're awesome. This is a good time to trust that person (or dog), to let him or her know that you're embarking on something intimidating and you'd like encouragement through the journey. It helps to have a belayer.

Believe in yourself.
At my lowest, I believed that I had no useful, marketable skills; all I was good at was politicking my way through my employer's byzantine bureaucracy. I had to break out of that if I was going to even begin the process of moving elsewhere. (Or of getting a promotion, for that matter.) I got a big sheet of newsprint and a box of goofy-big crayons, I went into a room by myself and closed the door, and I brainstormed. Crazy, wild, unrelated ideas about what I do, what I'm capable of, and what I am that is awesome. I wrote a lot of things on that paper, and many of them showed up on the next draft of my résumé.

Improve.
And then I thought about what I wanted my résumé to look like. Or, more specifically, what skills I would need in order to get the kind of job I would enjoy. I made a curriculum: books to read, topics to research, and projects to implement. Tuesday is homework night, for writing code. Here's the trick to making this palatable: Every time I worked on a curriculum item, I complimented myself on taking another step towards that new job. When you're in a hole, the very act of climbing up makes you see the sky. That's where I'm going, and I'm making progress towards it. Yay, me.

So there's an overview of how I improved my lot in life. The hardest part was overcoming inertia and getting started. Well, that, and persevering through to the goal. ;-) If you're happy where you are, don't forget to look around and appreciate that from time to time. Every job has its annoyances and challenges I imagine, but it is possible to find one where you feel fulfilled and appreciated, where your skills are useful, and where the challenges are fun. You deserve a job you enjoy.

Lurking Under that Resistance

noreply@blogger.com (Sharon) — Sun, 01 Jun 2008 21:05:00 +0000

Some of the topics at the AgileAustin Open Space revolved around a theme. Is Agile appropriate for critical systems (medical, life-supporting software)? Can we use Agile when we have a fixed timeline and a finite budget? Will Agile work when our software supports an always-on manufacturing floor? What about when developing strategic software, breaking new business ground? Are there times when Agile is not appropriate?

I believe the conveners are primarily asking these questions as proxies. They're at the conference because they believe in Agile, but they've been asked these questions by stakeholders they need to convince. So they're looking for help in crafting their arguments.

In my experience, resistance to Agile derives from an underlying fear. That fear tends to take some mix of two forms: "I've invested my career in getting good at one way of doing things, and you want to make me obsolete," and "My rear is on the line for a lot of money. I'm not interested in risking my rear while you experiment with your touchy-feely methodology. Just deliver."

When trying to convince someone, first sussing out his concerns and then pitching your argument to address them will make you most effective.

For the fear of obsolescence, convey that, while some ways of doing things may no longer be needed, the person is still valued, and he has skills and experiences that will help the team make the transition. Give that person a clear role, an obvious place of value, and his fears and therefore resistance should relax.

To those who are inherently change-averse, you can still work to improve the feeling of safety, to make the change more palatable. There are some folks, however, whom Agile doesn't suit. Let them find jobs as SOX auditors or something.

For those who seek assurances that this crazy experiment will deliver, on time and on budget, I take two tacks. I show them burndown charts, and explain how you can clearly see, "Does this trend line look like it's going to hit the finish line when you want it to?" Burndowns are very communicative graphics; they're a great tool. Second, I ask permission to try it for a month. Just, give me two sprints. Worst case, you've lost a month, which you would have spent writing half of a Business Requirements Document. Best case, you might have a few high-value, ready-to-ship features. That's a pretty good risk-to-return ratio.

Understand what fears are hiding behind their resistance. Address those fears (usually without making direct mention of them; fear tends to turn defensive if you point out a perceived weakness). Talk in their language, using their own levers, to present your case (e.g., talk numbers to a finance person). Finally, ask for something reasonable: "You don't have to do this forever, just let us try it for a bit, and then you can decide whether to continue or adjust."

Agile Open Space: On Certifications

noreply@blogger.com (Sharon) — Sat, 31 May 2008 03:18:00 +0000

The AgileAustin Open Space has kicked off. I found the opening session positive, engaging, really fun to be there. I'm chuffed because I felt confident enough to suggest (convene) a few sessions. One responsibility of a convener is to capture notes from the session. This blog post is meeting that responsibility.

Y'see, one of the sessions I proposed was entitled, "Certified ScrumMaster??" I wanted to gauge people's opinions of the CSM certification: Is it valuable, is it real, or is it just résumé-padding fluff?

I got my answer. The groans, grumbles, and rolled eyes around the room confirmed my suspicions. In this crowd at least, it is worse than irrelevant. It is counter to and detrimental to the philosophy of the Agile community.

After the proceedings broke into less formal conversations, I caught up with some community members whom I respect and enjoy. They elaborated on their earlier non-verbal remarks. It is not difficult to get a CSM; you attend a two-day class. That's it. That sounds like just enough knowledge to be really dangerous.

Why do we even need certifications? What does a certificate indicate about my real skills, abilities, and past experience? No, I inherently reject any model that sets up a gate-keeper-style hierarchy to knowledge—a system that says, "We know things; you don't. Your ideas and perspectives are not as good as ours until we bless you and permit you to be one of us (and your check clears)." I don't accept religions that do this, nor governments, nor software project methodologies, for Pete's sake.

The true flaw in the CSM is the name: Certified ScrumMaster. Go to a hiring manager and ask which she'd rather have, someone with 3 years' experience as a Scrum team member, or a Certified Scrum Master [trumpet fanfare]. Those in the know, know that ScrumMaster is the role; you hear it without the space. But to those who are not yet well versed in Scrum, it sounds like Mastery of the Scrum process; they inject a space between the words.

The Training page on the Scrum Alliance website says it plain: "The journey to mastery begins with..." and "These courses [CSM and CSPO] provide a solid foundation to help you make the paradigm shift to managing a project using Scrum." [emphasis added] They state straight up that this is the starting point. But the name of the certification doesn't say that. The opportunity for misinterpretation will get people into trouble.

Why does it get my dander up? Personally, because it threatens to be Another Damn Thing I gotta do to stay in the game. Professionally, because agile projects can be magnificent, and certifications smack of the process-for-process'-sake mindset that turns software development into a tedium. Philosophically, because neophytes will incorrectly elevate the merit of opinions from a Certified ScrumMaster, no matter how little experience he may have, and dilute and muddle the tenets of Agile.

Mike Cohn the other night joked about the CSM culminating in a tattoo. I don't know, man, I might put more stock in that, if the tattoo embodied the Agile Manifesto. (Embodied—ha!) It would at least convey the right level of commitment.

Simplest Responsible Thing

noreply@blogger.com (Sharon) — Sun, 18 May 2008 01:00:00 +0000

Someone on Saturday asked rhetorically, how do you reconcile the agile philosophy of "do the simplest thing possible" with good OO design principles. That apparent conflict stems from misquoting the first part. The more useful version is:

Do the simplest responsible thing that works.

That is, responsible to highly probable future features; responsible to your known performance demands; responsible to your business's security and reliability requirements.

Above all, responsible to your future teammates (and your Future Self) who will have to support and maintain that code. Happily, this last responsibility is nicely supported by the emphasis on "simplest."

Note also that it is "simplest," not "easiest." Your old familiar habits will be easiest, but if those habits were formed in a different paradigm—say... old ASP that you learned by osmosis (Hey, we all had to start somewhere.)—then it will take some dedicated study to turn the responsible thing, the simplest thing, into something you can do easily. Meanwhile, the state of the art in Simple will keep moving, but that just gives us something to keep striving towards. That's what keeps it interesting, right?