Tuesday, November 25, 2008

Even Agile Projects Need Vision and Concept

So you have heard about this strange word - 'Agile' . After some googling, reading some blogs and maybe some books you hear only promises how you will implement majority of your projects easily, in time and within budget. All you need is to put some team together, write some user stories, estimate them and start doing iterations. You track your velocity, write unit tests and more or less follow best agile practices while coding. And somewhere in the middle you find out that you are lost and not sure what is happening. Then you start to ask your self what had happen?

This is happening probably more often than we would expect. And the reasons are different. I will not try to find those reasons as lot of them are already described and you can find out how to prevent them.

I will concentrate on one that is for unknown reasons rarely mentioned in blogs and even agile books.

Even when you are doing agile software development (XP, Scrum) what you need is concept or vision for the project. But not only in the head but also on the paper. This needs not to be hundred pages document but document that clearly states what are the goals of the project.

In the number of agile posts, your project is starting with writing epics, stories and/or roles. But it is little bit confusing how to get those user stories. Advice you find the most often is to make user stories writing session where moderator guides meeting and the goal is to write as many user stories as possible. But how you can write user stories if you are not aware what is the main goal of the project? To be able to write good user stories (even epics) you must have clear idea what is the vision of the project.

To be able to write good user stories you must have vision document.

Some of the attributes of the good vision document are:

  • It is short
  • It clearly states goals of the project
  • It is read and understood by the software development team (and all other interested parties)
  • It is always up to date (changing with the project)

I believe these attributes state that vision document is agile

So if you are planning new project and want to do it right way I believe correct order of steps would be (note that very often the first step is left out and I believe it is the first mistake in the project):

  • Write vision document and communicate it to all interested parties
  • Write epics and user stories based on the vision document
  • Create your product backlog
  • Start with iterations
    • After few iterations review the project
    • If necessary change user stories
    • If necessary change vision document
    • Communicate changes in the vision to all team members so they are aware of the new course of the project

So vision document must reflect all the time your current goal of the project and this goal has to be clearly communicated to the team.

Be careful, doing agile project without clean vision and without adapting during the path is impossible.

Wednesday, November 12, 2008

Public Methods Should be Like Stories

I believe that most of the developers try to write code to be readable as much as possible. I will try to explain how I try to achieve this. From my point of view one of the most important things is to write public methods as stories. This means when somebody is reading your public method its implementation should tell with the sentence like methods what it tries to achieve. This way one can concentrate on the business logic that the method tries to achieve and not how that is achieved.

So I try to follow few short rules:

  • Instead of code within public method call number of private methods
  • Avoid loops
  • Try to minimize if statements
  • If private method is hard to read apply this rules to private method

Following this rules your public methods are easy to understand. It is easier to test if you are doing black-box testing. What may happen to your code is that you will have number of private methods if you implement mentioned rules also on private methods. But I don't consider this to be bad because in that case even private methods are easy to understand so if one should change your code it will be easier.

As opinion is easier to understand through example, I will show one method from my http://www.flexiblefeeds.com site.

Although example is in groovy I believe it will be easily understandable for all developers. Currently method looks like this:

def currentUserVote(Long articleId, boolean upVoting) {
boolean canVote = canCurrentUserVote(articleId)

if (!canVote) {

vote(articleId, upVoting)


I believe that is is easy to understand what the method does from the code itself. But to be sure, first it is checked if current user can vote. If user cannot vote method returns. If user can vote voting is done and then voting is registered.

Now let us see how this method can look like if the code would be embedded into this public method.

def currentUserVote(Long articleId, boolean upVoting) {
// decide if user can vote
if (!loggedInUserIsAdministrator()) {

// logged in user can vote if he didn't voted
if (userIsLoggedIn()) {
return !voted(loggedInUser().id, articleId)

// not logged in user can vote if he didn't voted and data is stored in session
if(votedInSession(articleId)) {

// perform voting
try {
String sql
if (upVoting) {
} else {
Article.executeUpdate(sql, [id:articleId])
} catch (Exception ex) {
log.error("Failed to vote up for article ${articleId}", ex)
throw ex;

// register voting
if (loggedInUser()) {
def a = Article.get(articleId)

try {
ArticleVoting voting = new ArticleVoting(user:loggedInUser(), article:a)
} catch (Exception ex) {
throw ex;
} else {
if (!session().votedIds) {
def votedIds = [] as Set
session().votedIds = votedIds
Having look at this method you can notice it is possible to understand what is method doing. But beside understanding what is method doing you are reading code. It means you are doing two things at the same time. Trying to understand business logic and trying to understand how this business logic is achieved.

Therefore in all cases I would recommend to refactor such code and to extract parts of the public methods into private methods.

Tuesday, November 11, 2008

It is very expensive to work with Grails

Just to make disclaimer immediately at the beginning. I don't really thing that working with Grails is really expensive, I would display it as expensive from the funny point of view.

This post is more advertisement then real post. So if you don't want just don't read it.

Small ad. One of my latest expenses, please have a look at http://www.flexiblefeeds.com.

So lets go to the point. Some time ago I discovered Grails. I tried to write few simple applications. Then I tried to write more complex applications. Then I was investigating advance features.
And very soon, less than a month after discovery, I realized that one is able to write real web applications with Grails more or less within minutes.

But if writing web applications is so easy, why not create real web application and put it on line. And there came the first idea. I wrote http://www.grailstutorials.com, payed subscription 20$/month and put it online. Visitors are coming, site is I believe well known within Grails/Groovy community so it stays online and I am still paying 20$/month. But these money can not be compared with satisfaction having real, visited web site online.

But writing web applications with Grails is still easy. So why not try another application. I implemented (actually still implementing) http://www.flexiblefeeds.com, payed subscription 20$/month and put it online.

Now I have two Grails based applications online, still trying to improve both of them. More or less I have idea about two or three more projects that I want to implement with Grails. What I am missing is time.

So why is it expensive to work with Grails:
  • You develop web applications very fast so you will need lot of money to pay web hosting
  • You develop web applications very fast so you will need most of your free time just to try all ideas you get
  • Grails is growing so fast that you will need lot of free time just to read all the blogs and nice things you can do with groovy/grails
So if you don't want to write web applications fast and easy just ignore Grails. If you want to write web applications fast and easy than it would be wise to try Grails.

Sunday, November 9, 2008

Flexible Feeds Launched

New grails powered web site is launched. You can have a look at www.flexiblefeeds.com.

On this site you can register RSS feed of your blog or feeds of your favorite blogs or web sites. Each feed is registered in different category so you can navigate articles by categories. To help others to decide if it is worth to read article you can vote for articles.

You should give a chance to this site and you will see it can be excellent source of news in the blogging sphere.

Why this site? If you are at least a little bit like me your RSS reader is full of feeds. Feeds are probably added to different folders but you need lot of time only to navigate through all new articles. What I am missing in readers is possibility to have kind of unique view and social aspects like voting on articles and tags on articles.

All that I miss in classic readers is supported in the first release of flexible feeds.

But I don't plan to stop here. I would like to have flexibility with feeds. Maybe I want to have different views for the same category. Or I want to combine different feeds. All this and much more is planned for the next version.

And for the end, I would be glad if you register RSS feed of your blog or feeds of your favorite sites.

Sunday, November 2, 2008

Grails Conditional Tags as Method Calls Trap - Part 2

In my previous post I was discussing how grails conditional tags should be used from the code. More or less post was about how to use conditional tags within if blog. Although I thought that my approach is good comment from Graeme Rocher opened my eyes. And therefore I decided to write short post because maybe this comment wasn't noticed by others.

I planned to write this post immediately next day but as I was busy with releasing first version of Flexible Feeds I didn't have enough time. By the way you can also visit www.flexiblefeeds.com :)

But let's go to the point. My approach with conditional tags was that if I want to execute something that depends on condition that is already implemented as tag you should use structure like this one:

if (g.conditionalTag() {true}) {
// execute some business logic

{true} part is actually closure that will get executed in the case that conditional tag satisfy condition. I must admit that this structure looks little bit strange but if I need not to copy/paste already existing code I am happy with that.

But as Graeme correctly noticed better approach in such situations would be:

g.conditionalTag() {
// execute some business logic

I agree that this is more readable and easier to understand.

In the case you need if...else approach then you still need version with the {true}.