Video from my presentation at Agile Warsaw

Here's the video from my presentation and the discussion about Agile Skills Project and our experiments in motivating developers at my company, that I had a chance to show at Agile Warsaw.

Do not ask my why the camera is 100% time focused on the wall, I have no freaking idea :) The voices are there, and that matters.

You can either watch it on Parleys: http://parleys.com/d/2019 or right here. Be warned: it's in Polish.

Getting rid of null parameters with a simple spring aspect

What is the most hated and at the same time the most popular exception in the world?

I bet it's the NullPointerException.

NullPointerException can mean anything, from simple “ups, I didn't think that can be null” to hours and days of debugging of third-party libraries (try using Dozer for complicated transformations, I dare you).

The funny thing is, it's trivial to get rid of all the NullPointerExceptions in your code. This triviality is a side effect of a technique called “Design by Contract”.

I won't go into much details about the theory, you can find everything you need on Wikipedia, but in the nutshell Design by Contract means:

• each method has a precondition (what it expects before being called)
• each method has a postcondition (what it guarantees, what is returned)
• each class has an constraint on its state (class invariant)

So at the beginning of each method you check whether preconditions are met, at the end, whether postconditions and invariant are met, and if something's wrong you throw an exception saying what is wrong.

Using Spring's internal static methods that throw appropriate exceptions (IllegalArgumentException), it can look something like this:

import static org.springframework.util.Assert.notNull;
import static org.springframework.util.StringUtils.hasText;

public class BranchCreator {
    public Story createNewBranch(Story story, User user, String title) {
        verifyParameters(story, user, title);
        Story branch = //... the body of the class returnig an object
        verifyRetunedValue(branch);
        return branch;
    }

    private void verifyParameters(Story story, User user, String title) {
        notNull(story);
        notNull(user);
        hasText(title);
    }

    private void verifyRetunedValue(Story branch) {
        notNull(branch);
    }
}

You can also use Validate class from apache commons instead of spring's notNull/hasText.

Usually I just check preconditions and write tests for postconditions and constraints. But still, this is all boiler plate code. To move it out of your class, you can use many Design by Contract libraries, for example SpringContracts, or Contract4J. Either way you end up checking the preconditions on every public method.

And guess what? Except for Data Transfer Objects and some setters, every public method I write expects its parameters NOT to be null.

So to save us some writing of this boiler plate ocde, how about adding a simple aspect that will make it impossible in the whole application, to pass null to anything other than DTOs and setters? Without any additional libraries (I assume you are already using Spring Framework), annotations, and what else.

Why would I like to not allow for nulls in parameters? Because we have method overloading in modern languages. Seriously, how often do you want to see something like this:

Address address = AddressFactory.create(null, null, null, null);

And this is not much better either

Microsoft.Office.Interop.Excel.Workbook theWorkbook = ExcelObj.Workbooks.Open(openFileDialog.FileName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

The solution

So here is a simple solution: you add one class to your project and a few lines of spring IoC configuration.

The class (aspect) looks like this:

import org.aspectj.lang.JoinPoint;
import static org.springframework.util.Assert.notNull;

public class NotNullParametersAspect {
    public void throwExceptionIfParametersAreNull(JoinPoint joinPoint) {
        for(Object argument : joinPoint.getArgs()) {
            notNull(argument);
        }
    }
}

And the spring configuration is here (remember to change the namespace to your project).

<aop:config proxy-target-class="true"> 
    <aop:aspect ref="notNullParametersAspect">
        <aop:pointcut expression="execution(public * eu.solidcraft.*..*.*(..))
                          &amp;&amp; !execution(public * eu.solidcraft.*..*Dto.*(..))
                          &amp;&amp; !execution(public * eu.solidcraft.*..*.set*(..))" id="allPublicApplicationOperationsExceptDtoAndSetters"> 
            <aop:before method="throwExceptionIfParametersAreNull" pointcut-ref="allPublicApplicationOperationsExceptDtoAndSetters"></aop:before>     
        </aop:pointcut> 
 
        <task:annotation-driven>
            <bean class="eu.solidcraft.aspects.NotNullParametersAspect" id="notNullParametersAspect"></bean>
        </task:annotation-driven>
    </aop:aspect>
</aop:config>

The "&&" is no error, it's just && condition escaped in xml. If you do not understand aspectj pointcut definition syntaxt, here is a little cheat sheet.

And here is a test telling us that the configuration is succesfull.

public class NotNullParametersAspectIntegrationTest extends AbstractIntegrationTest {
    @Resource(name = "userFeedbackFacade")
    private UserFeedbackFacade userFeedbackFacade;

    @Test(expected = IllegalArgumentException.class)
    public void shouldThrowExceptionIfParametersAreNull() {
        //when
        userFeedbackFacade.sendFeedback(null);

        //then exception is thrown
    }

    @Test
    public void shouldNotThrowExceptionForNullParametersOnDto() {
        //when
        UserBookmarkDto userBookmarkDto = new UserBookmarkDto();
        userBookmarkDto.withChapter(null);
        StoryAncestorDto ancestorDto = new StoryAncestorDto(null, null, null, null);

        //then no exception is thrown
    }
} 

AbstractIntegrationTest is a simple class that starts the spring test context. You can use AbstractTransactionalJUnit4SpringContextTests with @ContextConfiguration(..) instead.

The catch

Ah yes, there is a catch. Since spring AOP uses either J2SE dynamic proxies basing on an interface or aspectj CGLIB proxies, every class will either need an interface (for simple proxy based aspect weaving) or a constructor without any parameters (for cglib weaving). The good news is that the constructor can be private.

Agile Skills Project at my company

Unfulfilled programmers

Erich Fromm, a famous humanist, philosopher and psychologist strongly believed that people are basically good. If he was right, then either our society is a mind-breaking dystopia or we have a great misfortune of working in a field that burns people out, because many IT people I know are more like Al Bundy than anyone else.

Why is being a couch potato something wrong? Happiness can be achieved in many different ways, but not by passive pleasures. One way of pursuing happiness is by self realization and while self realization can happen in any activity, it's makes perfect sense to have it at work, where you spend one third of your life time anyway.

But many developers I know, consider work as something boring at best, dreadful at worst. True, programming can be awful, when you have to dig deep into a terrible code base without any perspective for a change, but IT is vast and you can always find something interesting, and once you learn it, you will find a way to make money on it, either by changing position inside your company or changing your employer altogether.

Yet most unhappy IT professionals don't do anything to change their situation. The main reason for that is, because it requires a lot of learning, and learning at home is not the most beloved activity for a couch potato.

So why are developers turning into couch potatoes in the first place? Why the last thing a typical developer will do back home is learning and polishing his skills? There are plenty of reasons for that.

The three main roots of an IT couch potato

First, our work is tiresome. Nearly every job offer you can find mentions “able to work under pressure” and “flexible long working hours” in the requirements. This translates directly to the “burn-out” phenomenon.

Second, the technological landscape is changing overwhelming fast. Unless you work for a slowly adapting institution like a bank, your skills will be outdated in a few years time. Sure the deceased Sun, god help us, granted Java developers four years of relative stagnation, but that's an exception and it's going to end soon enough anyway (unless, of course, these are just convulsions before slow death of technology). You better learn and you better learn fast, or you'll have no other option than to promote yourself into management.

Third, just how long can you sit by your computer everyday? Yeah, I know, some people spend years playing WoW, Eve and alike, barely moving. I am a sinner myself, with Steam reporting over 350 hours in Modern Warfare 2, 200 hours in F.E.A.R. 2 multi, and countless months of my life wasted by Sid's Civilization. But for not-addicted, it's just simply stupid, not to mention unhealthy, to have your ass integrated with the chair. No matter how comfortable it may be. There is more to life than that.

Case Study at my company

It all started with a few SQL programmers grumbling about how they are bored to death, and how they would like to switch to OO programming. I'm not a person who waits, so next thing I did was asking our management if they could move those guys to Java/C# projects. And the management was all for it, with just one requirement: they would have to first learn our technology stack at home, not to be totally lost and unproductive. After all, the more technologies an employee know, the more valuable he is for the employer (think about switching people between projects).

A few months later and nothing has changed. I'm asking sql guys how the learning is going, and I get the answer: it hasn't started yet.

Now, I know the best way to learn something is by hands-on experience at work. After all that's why I've been changing my job a few times: to have a real world experience. It's easier to learn french if you move to Paris. And learning at home is hard because of the aforementioned reasons. The very same reasons, why you get only 650 people on a free conference, like Javarsovia.

So what can we do, then? How about we remove all the obstacles? How about we make learning at home fun, satisfying and profitable. How about we provide  motivation and feedback. How about we also solve the never-ending dissonance between employee's financial and employer's productivity expectations on the way. Sounds interesting? Let's try, then.

First: make it profitable.

Up to some point, people get motivated by money. It won't work if you are already earning enough to pay for everything you need, but in a country like Poland, to be able to build/buy yourself a house, you have to be making many times the average salary. So here, money is still a major motivator. Every year, every developer goes back to his boss and says: I want more.

Guess what, your boss wants to pay you more. No kidding. After all Henry Ford's said:

“There is one rule for industrialists and that is: make the best quality of goods possible at the lowest cost possible, paying the highest wages possible”.

Highest wages. You boss really wants to pay more. But to stay in business, the company needs you to either improve the quality or productivity. Both mean more money to the business, and more money to pay you with. If you consider that, the goal of a developer who wants to learn something new (or get better at something) is on the way to make the company more profitable. After all, this is software development – you never know what technology you gonna need tomorrow.

This works both for completely new stuff, and for learning something that company is already quite good at. If you know several technologies that the company is working with, you are more valuable, because you can handle more projects (you boss may think in terms of reallocating resources).

After thinking about all of this I went to my bosses and asked them: will you pay more to the people who learn different technologies at home? Even when they can't use them right now at work? Will you give a rise to those Oracle guys, if they learn Java?

The answer was: definitely! They actually said that every time a developer asks for a rise, they ask him back: what have you done in the last year to improve your market value? What have you learned? Because every time an employee's market value increases, the company's value increases.

Simply speaking: more skills means more money. Both for the developer and for the company. It's amazing, how often people forget about it. Making it crystal clear can give you a motivational boost to do something at home and a nice perspective. You don't have to switch your job to get a rise. You need to learn more, and they'll happily pay you more.

Second: make it easy

The main question with learning is where to start from? And for software developers it's the most important, most difficult question, because there is no way to learn everything, because spending years studying can be simply a waste of time, if the technology is dead/outdated the moment you get productive with it. What should I learn or why should I learn at all, if the risk of wasting the most precious thing in my life, my time, is so high? How do I decide what to learn.

Lets make learning safe and easy.

Your best bet is to start with something that has much longer life expectancy, something that will help you right away, no matter what a technology you have to work with in your next project. And something that is relatively simple to learn: agile skills.

These are skills of an agile developer, well established, well recognized, and not going away any time soon, because we still do not have anything on the horizon that could surpass them.

Yeah, I know, the world 'agile' is so popular nowadays, that even my grandma is agile, but lets go for a solid list of things agile. No bullshit theory, no marketing mumbo jumbo, give me a precise, distilled and refined list of things I should learn, things that will help me, things worth spending my time on.

Here it is:

The Agile Skills Project

The project is all about self improvement and learning. It's a great inventory of “ isolated, learned, practiced, and refined” agile skills, with definitions, resources, descriptions of steps to mastery and success stories. Take a look at the “Pair Programming” page, for example.

All the skills are divided into different areas: Business Value, Collaboration, Confidence, Product, Self Improvement, Supportive Culture, Technical Excellence. You even get a nice mind-map with it.

This is a single reference point for all those who do not know where to start or where to go next. All these skills are in high demand on the market and with a very long Time-To-Live. The best thing is though: no matter what technology you gonna work with tomorrow, you can benefit from them.

I took the list from the website, tidied it up a bit, refactored it for the needs of my company, and proposed it as a Request For Comment, a wiki page, where everyone gets to discuss and shape up the idea, before we give it to the management.

Soon we had a discussion. It wasn't easy to make everyone understand the concept, but after a while people joined in, and we added some more stuff.

Level up!

The Agile Skills Project is more than a simple index. It tries to create a learning ecosystem, by defining quests:

"Quests" are on-the-job experiments, self-assessments, peer-reviews, course experiences or other activities intended to help a person better apply a particular agile developer skill set.

It's a bit like a Role Playing Game. You have your quests, you do them, you get experience. For experience you get more money and new toys (technologies) to play with.  It's fun. Billions of MMORPG players cannot be wrong.

But to make that happen we need something every game has: feedback.

Third: give feedback

OK, so we have a bit of motivation (money) and a list of goals (agile skills). Who is going to give us quests, and who is going to tell us we did a good job? How will we have our feedback?

The first and most important thing, is to see the results of you actions. Otherwise you loose focus and motivation (money can only get you that far). Therefore you should create a list of quests you have done. Put it on the intranet or somewhere, where you can show it to others. It's important, because you are going to share it with your mentor.

Yes, a mentor. Choose someone from your company, someone you trust, someone you respect. It doesn't have to be an Einstein. Meet with this person once a month, during your work-time. An hour should do. Discuss with your mentor what quests you want to accomplish this month. Could be anything, reading an IT book, learning new programming language or taking another step to master one of the agile skills from the list. Tell your mentor when you'll be done. Meet together again next month, and either put the quest in your done-list, or mark it as 'failed'.

The role of the mentor is to listen to you, remove obstacles, help you choose a good path and give you feedback.

You'll be surprised by how much the meeting with your mentor motivates you. It works much better than money: you don't want to fail in the eyes of the mentor, because this is the guy you respect, and you want him to respect you as well. And once you see your constant improvement by filling the list of quests done with your mentor, it gets addictive.

Smells corporate?

How is this any different to what you can sometimes see in a corporation, with a year long plan of tasks your boss is giving you to accomplish to get your bonus?

Well, first of all, these will be your quests, chosen by you. Second, you will choose your mentor as well. Your boss usually doesn't know a thing about what you are doing. Third, it's all about your self-improvement, not meeting some company goals. You get better at something, the company gets better at something. After all a company is not much more than the people working at it.  Fourth, it's a fast feedback cycle, you do not have to wait till the end of the year to get it.

And finally, it may be a bit corporate, because I have never seen any small company doing anything like this. But even if it is, it still seems like worthwhile. Anything to get me out of the couch.

Discuss

It's a bit too early to tell whether the idea will be successful. We have just started. Fo me it is already helpfull, because with a list of quests done I have have a feeling of progress. If you'd like to discuss this, and other ways to animate software developers to do something more, I'm leading a meeting at Agile Warsaw group about it, on the 20th of September, 19:00. Feel invited.

By the way, here you have a trial of "other ways to animate" from our internal TouK Code Jam Party, we held a week ago. Doesn't look mych corporate, does it? 

NYAC & COOLuary 2010 review

NYAC stays for Not Yet Another Conference, and it gives a promise I was happy to verify. The event took place in Cracow on 19th-20th of June, thanks to Grzegorz Duda. Tough timing I'd say, just a week before Javarsovia, but the audience was supposed to be small, so that wasn't a problem. NYAC was actually two things: a one day conference with carefully chosen speakers that got a bit more time than usually, and another day of an unconference.

If you didn't have a chance to participate in an unconference (Open Space Technology), it's totally people driven. Everyone is able to start a meeting, and it's usually a discussion, not a lecture.

But let's start from the beginning. I got there on Friday evening, and my luck was definitely with me, as I bumped into Paweł Lipiński at a gas station. He warned me about the post-soviet hotel, so we walked back carrying loads of beer, that helped shield us from the ugly face of socrealism and it's terrible architecture. Well defended, together with Wojtek Erbetowski, we spend the late hours enjoying the drink and a smalltalk.

The first day started.

So what's so different about NYAC, you ask. First day is just a conference, after all. True, but Grzegorz had a great idea, to make a survey about the best polish java speaker. He used the outcomes to invite some of the most interesting people in our field. He asked them to make a few lectures, one after another, and he gave them more time than usually (which turned out to be not enough anyway), and a much smaller audience.

The effect?

Well, it's like a difference between a stadium-sized concert, and a jam session in a private house.  The second one allows you to be more involved, and get much closer to the source of fun. Is it the way to do conferences? Yes, but only if you have the top guys out there. And that was the case. Have a look at the agenda, the only problem you could have is to decide which session to choose from.

Fortunately, being here and there, I've already seen some of the presentations, so it was a bit easier to me. Sławomir Sobótka had three great talks about Craftsmanship, Domain Driven Design and JPA/Hibernate traps (we all know that JPA 1.0 was a big step backward, compared to pure Hibernate, but Sławek had some really great examples of the most popular pitfalls). Szczepan Feber with Łukasz Milewski gave us a handful of good tips about continuous integration. Igor Czechowski talked a bit about his nightmares with Maven. Paweł Lipiński warned me that I may not find anything new in his talks, so I skipped them, but I really wish there was a camera, since Paweł is a great speaker and it's always refreshing to see his enthusiasm.

All together it was a condensed, great event, that I've left with a nice set of notes and a mind full of thoughts.

Then there was a party, though Grzegorz didn't give the address, just the name of the pub, and as with all the names, it was easy to forget and hard to find using GPS.

Great aspect of going to so many conferences (I've been to six this year) is that eventually you get a nice pack of people to drink with, but with such a small scale (there was something about 50 attendees) it's easier to get to know everyone and not feel lost in the crowd anyway.


Some people stayed till like 3am, but since I was kind of on a mission gathering/crunching knowledge, I decided to get back at midnight.

The second day was all about self organized groups of talkers. We had a flipchart where everyone could post a proposal, then we grouped together similar topics, and sorted them out considering whether the guys we wanted to join in, were leaving early or waking up late. Seriously. After all, talking about DDD without Sławek or about A/B/TDD without Paweł would be like wasting resources.

The only “real” presentation that day, was a sponsored talk from Tomasz Skutnik (e-point) about class loaders in JEE, and it was unexpectedly good, I must say.

I also had a chance to animate a smalltalk, which I used to confront and verify some of the ideas I've been preparing for my Javarsovia presentation. The feedback was good, and some of the points from the discussion helped me to refactor my final talk.

All together it was a great weekend, and I can recommend NYAC/COOluary with my heart. It's a moving conference, every year in a different city, so stay tuned to Grzegorz's site, and don't forget to visit the event whenever you have a chance.

GeeCON 2010 general impressions

GeeCON 2009 in Cracow was a wonderful experience, and this year Poznan held the conference. If you ever wonder whether GeeCON is worth the time and money, the answer is plain and simple: definitely yes.

I'm not able to give you a full review this time, as I'm leaving tomorrow for Paris, and I haven't prepared myself yet, but let me summarize the most important topics.

There were two different presentations about Erlang way (Actor and Agent models) of solving the problem with concurrency. One was a general overview of the problem and possible solutions running on JVM, and the other was about Akka Project/Platform that looks very interesting and above all, is simple to use (at least from what we've seen at the presentation). So far I've been trying to shield myself from concurrency problems with web servers, stateless services and optimistic locking on database level, but the solution presented here is really appealing. I'd love to try it out.

Joonas Lehtinen had a very nice lecture about Vaadin. There was a talk about Hades which is probably going to replace the solution I usually use (hibernate-generic-dao). Kuba Kurlenda is testing it on real project right now.

Stephan Herrmann was talking about an evolutionary idea for Object Oriented Programming:  Object Teams. This may be the next big step we need, but it would have to gain some momentum and find a real life use in a big project. Unfortunately Object Teams do not yet have a successful example to follow. The main question I see is whether it's worth investing the time of your team, while everyone already knows about design patterns, which solve similar problems.

There was a presentation about Spring Roo framework which is something you should know before you move to Grails or Ruby on Rails. Even if you do not plan to do it, it's a great way to create prototypes.

Waldemar Kot had a very condensed, content rich but easy to learn lecture about Complex Event Processing. It was definitely worth listening to. I'll try to infect my SQL friends with this idea, as it seems like something they would really like to do, when they move from PL/SQL to Java. Thomas Sundberg repeated his talk about Software Craftsmanship that he gave at Agile Central Europe. There was a little bit about Comet (push style Ajax), agility, OOP and lots of other interesting stuff.

And there was a great party, but that's a completely different story.

If you have a chance to go to GeeCON 2011, do not hesitate to.

PS: all the pictures come from the official GeeCON gallery. I don't know about the authors, though.

Open Code Review

Łukasz Lenart at Warszawa Design Patterns Study Group gave a very interesting presentation about Open Code Review in his company (you can read the details here). I've failed to notice whether it's his own idea, or somebody's else, but that's not as important as the fact how well it works.

Open Code Review, in short, is when a small group of programmers (up to 6) meet once in a while for a brainstorming session, take some printed out code, and try to find out, for an hour or so, what could be done better.

It's basically about sharing knowledge and insight with others. It can be a very beneficial experience, especially for teams that do not use Pair Programming, or to pairs that do not switch very often, but I think anyone can find it useful.

The power of this technique is reflection. When we code, when we create software, we often find ourselves thinking in a specific way. We tend to take things for granted. We start to look at the code with our mind set on a particular solution, and as a result, we can't see the forest for the trees. This is how human mind works, it's nothing new. After a few weeks of walking the same route, you stop noticing the buildings along the way.

It's also one of the reasons why Pair Programming is so efficient. “You cannot solve a problem with the same mind-set that got you into the problem in the first place”, as some believe Einstein said. Having another mind next to you, looking at the same code, gives a chance to spot the problem as it is being created, but more importantly, it is very helpful in the process of discovering the best design. Open Code Review works in a similar way. It allows you to learn different mindsets and different styles of solving problems. Nothing is as refreshing as being able to see from other points of view.

Apart from this, OCR meetings also help in spreading knowledge (people read different books) and experience (people work on different projects with different technologies and problems).

This idea inspired me to organize similar meetings at TouK and I've got very good feedback so far. Our formula crystallized by looking at the the past and finding out what was cool and what was not. Our take on Open Code Review is quite different to what Łukasz proposed.

But first, things that we do the same way: we take maximum 6 people (plus the moderator), we gather them up in a conference room, we hand out code printed on paper.

The code we take is not Open Source, as Łukasz suggested. His reasoning was, that if you take somebody's code, it could turn personal, we all put some heart into our work, after all. This is where we disagree: we have found it very valuable to take internal code from our projects. We are not afraid of our code being criticized. As Robert C. Martin wrote: every good programmer should get used to professional code review. Bad programmers can benefit from it even better. And if you have some Prima Donnas in your team, unwilling to hear constructive critique to their code... screw them. Nobody's able to work with them anyways.

Second thing we do differently, is that we do not comment the code on paper. We actually have a working environment (IDE and stuff) with three keyboards/mice, thanks to USB hubs. We either comment the code directly, writing TODOs, for bigger changes that would take more time than it's left, or we do the refactoring right away. This allows us to make a commit to the repository after the session and improve some project a bit. It's also much easier to talk about the code, when you have a keyboard at hand. Sometimes it's just way simpler to show what you mean than to explain it with words.

We also take a bit longer for each meeting: usually an hour and a half, or two hours. This is the optimum time, to learn and do something meaningful, and not get tired. And we do not split attendees into teams, we want people to talk a lot, and we want people to talk with each other.

So what is our recipe for an Open Code Review? It's like this:

Ingridients

1. Invite anyone who wants to participate, from all over company, but take no more than 4 to 6 programmers plus a moderator
2. Take a conference room with a laptop, three or four keyboards/mice, and a projector
3. Set up the meeting for 1.5 or 2 hours
4. Moderator prints out a class (or a few classes) that
1. has between 150 and 300 lines of code
2. has unit/integration tests for all non trivial methods
3. is from a project that works with our environment (IDE/Maven etc.)
4. is not trivial and not completely shitty (that would be too easy and nobody will learn anything)

Instructions

1. Give everyone printouts and 10 to 15 minutes to read the code and make notes
2. Ask whether you should start top-down or from some other point in the code (some classes are broken conceptually and it's better to fix them by talking about their responsibilities first). If in doubt start from the top.
3. For every block/method/property ask whether anyone thinks that it could be done better. The person that has the idea, has the power (keyboard) to do it.
1. If it's a small change, fix the code
2. If it's a big change that would take longer than the meeting, write a TODO
3. If someone disagrees, talk, talk, talk until consensus is found or you agree that you disagree and move on
4. Run (write if needed) tests, to make sure the code works. This is a real refactoring, you cannot break the code. Broken code is not considered better.
4. If you cannot find anything more that you could get better, use the principles from “Clean Code” (or some other book) to guide you.
5. At the end of the meeting, commit the code.

Things to remember

If you are the moderator, remember to shut up and keep quiet. You probably had a bit more time to read the code so it's natural you'll have noticed more flaws, but let the people do the exploration and discovery. When they don't have anything else to say, then it's the time for you to speak.

If you are the author, no matter what, DO NOT EXPLAIN the code. Either the code speaks for itself, or is badly written.

Enjoy.

PS: this practice has been unfortunately stopped, because I've started to go to conferences and could not moderate any more. Do not make my mistake and communicate clearly, that ANYONE can call for an Open Code Review, and that the moderator should be changed every two weeks or so. I've failed at doing that, and now I have to revive the whole thing.

Boy Scout Rule in practice

I've started doing Scrum in late 2008 (thanks to Piotr Burdyło). And though I've immediately seen benefits of practices like daily standups, sprint planning, reviews and retrospectives, I had a big problem with finding out how to deal with refactoring within this method.

Before Scrum, whenever I found a place in code that I thought should be done better, I'd put a TODO comment. I would return to these comments whenever I saved some time on what I was doing, or when I decided that it has already been too ugly for my standards. And since my standards are pretty tight, I've been  (and making others) refactoring quite often and it worked well for me.

When doing code review, I'd write TODOs, discuss them with the authors of the code, and make them do clean up as the top priority.

But what were my options in Scrum?

1. Don't tell anybody, and just use your left over time to clean up the TODOs

This is against transparency, which Scrum is advocating, and against my moral backbone (no lying). And since you are evaluating tasks/features better and better, sooner or later you'll have no left over time for TODOs anyway. Ergo: this won't do.

2. Create additional tasks/features for refactoring

These are not visible from the product owner point of view, so some Scrum Masters are strongly pushing against them.

Ok, so I had to choose the second option, and make my Scrum Master live with it. But then, another problem emerged: unless you put a cleaning task for every class that has TODOs inside, sooner or later you'll end up with tasks like “Do all the TODOs in my Big-Ugly-Module”.

This will happen because doing TODOs may have very low priority, because people in a hurry don't bother doing them, and because some people don't write TODOs at all, rather thinking: “yeah, this is ugly, lets fix it, when we fix the rest of the module”.

So it seams that your code is predestined to go down the great spiral of (bio)degradation, until your team can't stand it anymore and somebody asks for a Scrum task to clean up the mess.

Is there a solution to this? Is there a third way?

Sure there is.

What if we can switch the direction the code quality goes in? What if our code can get better with time, instead of getting worse? That would be cool and it would solve our problem with TODOs in Scrum.



Boy Scout Rule

Leave every code you read in better shape than you found it.

Ha! That sounds like something everyone would sign under, and completely forget about a few minutes later, right? I mean, phrases like this sure look nice, but the real battlefield, the front-line, is a mean and messy place, right? You sit in your trench, trying to survive and keep the project alive, while bullets fly above your head. How can you try to make things better, when you couldn't keep them clean in the first place? No way to do it, man, there is too little time, right?

Wrong.

Let me show you how to use this rule in practice, without any significant time burden.


Real case scenario

You are in the middle of writing an application, you take a task from the Scrum white-board. It's a new feature. It says: “When importing orders, every shipping address should be verified. If it's not in our shippable zone, it should be canceled (status change + send an email to the frontend application)”.

Ok, so you want to write a new acceptance test, for this feature. But first you need to know what to test, which part of the application is responsible for importing orders. You search the project structure, and you spot the OrderService interface. You nose tells you, that it should be somewhere there. You take a look.

public interface OrderService {
    /**
     * Imports orders.
     */

    public void importOrders();
    /**
     * Export orders.
     */
    public void exportOrders(DateTime date);

    /**
     * Create raport of placed orders
     */
    public OrderRaport createRaport(DateTime date);
}

Yeah, it's there. The importOrders() method. You search for implementations, and as you expect, there is an OrderServiceImpl.

WTF is with this blur, you ask. It's intentional. It's how much you see during your first second of looking at the code. At the first second you, as a good writer, have already noticed two things:

1. The method has 30 lines. It's probably too long. Good method should be as short as possible. This, according to Robert C. Martin, means between 1 and 7 lines.


2. The are several different BLOCKS of code.

What does the second thing mean? It means, that the author has noticed the first thing as well, so he decomposed the method into different blocks, by putting an empty line between them.

This is so natural, so popular, nobody thinks about it anymore. We put empty lines between different blocks of code, to help us read the code. When we read the code, we can skip such blocks, because we already know, what those blocks do.

We put together similar stuff, so we can put a name into our mind-map, that given block does something. Next, we can fast read and skip it consequently.

There are two big problems with such method:

1. it requires you to read all the details (every line) of the code at least once, before you put names of those blocks in you mind


2. it is not the way Object Oriented Programming is supposed to separate stuff that make a single concept

So how about fixing it, while we read it? We have to read and understand it anyway. How about not keeping the names of blocks in our memory, but putting them into the code instead.


Comment every block of code

You are doing it anyway, but instead of saving the names/explanations in your head, save them in the code for a moment.

So our code will look like this:

@Override
public void importOrders() {
//create date before importing from web service
    DateTime date = new DateTime();

//import data transfer objects from web service
    List<SalesOrderExportDetail> orders = salesOrderWS.getSalesOrdersFromWebService();

//create summary for importing orders
    SalesOrderImport salesImport = new SalesOrderImport();

//for each order try
    for(SalesOrderExportDetail salesOrder : orders) {
        try {

//convert it to domain object
            Order order = new Order();
            order.setValue(new BigDecimal(salesOrder.getValue(), new MathContext(2, RoundingMode.HALF_EVEN)));
            order.setAddress(convertToAddress(salesOrder.getShippingAddress()));
            order.setBuyerAddress(convertToAddress(salesOrder.getBuyerAddress()));

//calculate vat
            double vat = calculator.vatRate(order.getAddress());
            order.setVatRate(vat);
            BigDecimal value = calculator.value(vat);
            order.setVatValue(value);

//calculate value in PLN
            Currency curr = order.getCurrency();
            if(curr != Currencies.PLN) {
                order.setPln(converter.convert(curr, order.getValue()));
            }

//save in repository
            orderRepository.save(order);

//prepare information whether it was succesfull                
            salesImport.imported(order);
        } catch(Exception e) {
            salesImport.notImported(e);
        }
    }

//save the summary for importing orders
    salesImport.setDate(date);
    orderRepository.save(salesImport);
}

Put the comments without any indentation, so that you won't forget to get rid of them, and they won't mix with other comments in the code. Make those comments verbose, make them say everything that is important on this level of abstraction. You are a programmer, you probably write faster than you think, so there was no additional time spend on this action.
Now for the second step.


Eliminate blocks of code using explicit names

The goal is to compress all the information from inside the block and the comment into one-liner. That saves the time the reader needs to get the meaning of the code next time. It usually means, replacing the block with a method, with a name created from the comment. So for example this:

//calculate vat
    double vat = calculator.vatRate(order.getAddress());
    order.setVatRate(vat);
    BigDecimal value = calculator.value(vat);
    order.setVatValue(vat);

will be replaced by this:

order.calculateVat();

Who said that the new method has to be in the same class? In this situation, it makes much more sense to put the use of the calculator into the order, after all it has all the data (we are using aspectj load time weaving to get the calculator into the order, but there are plenty of other methods if you don't want to use aspectj).

And this:

order.calculateVat();
//convert it to domain object
    Order order = new Order();
    order.setValue(new BigDecimal(salesOrder.getValue(), new MathContext(2, RoundingMode.HALF_EVEN)));
    order.setAddress(convertToAddress(salesOrder.getShippingAddress()));
    order.setBuyerAddress(convertToAddress(salesOrder.getBuyerAddress())); 

Will be replaced by this:

Order order = orderConverter.toOrder(salesOrderDto);

Here we have decided to put the body inside a new class: OrderConverter, because the convertion is a serious responsibility and the OrderService look like it's got other things to do already (Single Responsibility Principle).

Even one-liner can be a bit fixed, for example in this part:

//create date before importing from web service
    DateTime date = new DateTime();

The comment is put, because the name of the variable does not communicate it's intention. We can get rid of the comment if we give the necessary information to the reader in other way. For example like this:

DateTime dateImportStartedAt = new DateTime();

We should eliminate every block and split every part of the code that serves a different need. Even for-each loops and try-catch expressions. For-each responsibility is to iterate over a collection, and call someone else to do the job on an element. Try-catch is responsible for handling an error, so somebody else should do the unsafe job for it.

This is the Single Responsibility Principle on a method level. Make every method have only one reason to change, and your life (and the readability of your code) will be better.

Since these are very basic and easy refactoring steps, that your IDE does automatically with little effort from you, the time burden is insignificant. You had to understand the class anyway, and on the way, you've made it better, easier to understand. Now the part of your class responsible for imports looks like this:

@Override
public void importOrders() {
    DateTime dateImportStartedAt = new DateTime();
    List<SalesOrderDto> salesOrderDtos = salesOrderWebServiceClient.getSinceLastVisitOrderedByNumber();
    ImportSummary importSummary = tryToImportEach(salesOrderDtos, dateImportStartedAt);
    orderRepository.save(importSummary);
}

private ImportSummary tryToImportEach(List<SalesOrderDto> salesOrderDtos, DateTime dateImportStartedAt) {
    ImportSummary importSummary = new ImportSummary(dateImportStartedAt);
    for(SalesOrderDto salesOrderDto : salesOrderDtos) {
        importSummary.add(tryToImport(salesOrderDto));
    }
    return importSummary;
}

private OrderImportOutcome tryToImport(SalesOrderDto salesOrderDto) {
    OrderImportOutcome orderImportOutcome = null;
    try {
        orderImportOutcome = importOne(salesOrderDto);
    } catch(Exception e) {
        orderImportOutcome = new OrderImportFailure(e);
    }
    return orderImportOutcome;
}

private OrderImportSuccess importOne(SalesOrderDto salesOrderDto) {
    Order order = orderConverter.toOrder(salesOrderDto);
    order.calculateVat();
    order.updatePlnValueIfNeeded();
    orderRepository.save(order);
    return new OrderImportSuccess(order);
}

Every method has a meaningful name. No more than 7 lines of code per method. You don't need to divide code into blocks, methods are an object oriented solution to divide the code. By the way, you've delegated some responsibilities to other classes. You've refined the code, made it more precise, more clear, more readable.

But somewhere in your head there is a voice saying: “Hey, I had just one, 30-lines method, now I have four, taking the same space. If I do it to other methods, I'm gonna have like 15 methods per class. I'll get lost, it's no way easier for me”.

But that is, because you have one more big mistake to fix.


The name is the responsibility

Have a look at the name of the interface: OrderService. Can you tell me what this class is responsible for? Every class should have just one responsibility, what is it for OrderService?

Everything about orders?

What kind of responsibility is “everything”? There is no such thing as “everything”? Thinking this way you can create single class named God-Emperor and end your OOP right there. You'll never need other classes anymore.

No, my friend. The name SomethingService is a great mistake, just like a SomethingController or SomethingManager. I know quite a few SomethingManagers in real life, that you wouldn't be able to find any responsibilities for. They are called that way, because this is what they do: NOTHING. They just are.

But we do not speak corporation-bullshit (even though some of us work at corporations), we are Agile developers, we are writers, we name things as they are.

So our OrderService interface should be split into, let's say: OrdersImporter, OrdersExporter and OrdersReportFactory. That would make responsibilities and our intentions clear. If you do that, you end up with a WebServiceOrdersImporter implementation class, that has only 30 lines, 4 methods, only one of them public.

Now that's simple, isn't it?


Conclusion

It doesn't have to be expansive or difficult to make code better while you are reading it.

You shouldn't wait for the code to get really ugly. You shouldn't write TODOs only for obvious problems. Every time you have to read and understand some code, ask yourself a question: Can I make it easier? Can I make it more readable? Can I make it better?

Take at least a small step, every time you answer is yes. Good is better than good-enough. This helps turn the tide, change the (bio)degradation into positive evolution. In the end, your code gets better with time.

No one writes good code right from the start. Good code evolves from normal code, by using the Boy Scout Rule.

And if you cannot find any way to make the code better, at least eliminate blocks of code with methods. Stick to "7 lines per method", and "Single Responsibility of a method" rules.