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Review - The Object-Oriented Thought Process, by Matt Weisfeld

In this post, I would like to point out what I understood after closing my eyes and thinking about what  exactly I have learned from this book. That means the layout of content does not follow the book.
From Procedural to Object Oriented Once upon a time, there is an issue that it is very hard to test and debug in Procedural programming because the data is sometimes global and can be modified by multiple functions.

Object-Oriented (OO) programming addresses these problems by combining both data and functions into an object. That means only functions belong to the object can access its own data.

Let us check the below two different approaches for a case that we want to transfer information between clients and servers across a network.

-    Procedural programming: a client (browser) transfers a JSON data to a server which needs to know how to process with this data. In order words, a handshaking agreement must be defined for the client and server in order to work together.
-    OO prog…

Building a Wizard with Chain of Responsibility Pattern

What is the Idea? We want to create a page that there are some steps and each step has its own business. Users are able to click on a step and its status could be changed. Primefaces owns a component "Wizard" but it it quite hard for us in order to apply our very specific and complicated business domain logic on each step; even we cannot click on a step of this component.

We somehow are able to use the component "TabView" works with a strong back-end mechanism. A backend mechanism! what do I mean? Yes, we need it because we want to abstract the behaviors of each step otherwise we will get trouble with many events handling. Obviously, each step has some behaviors  such as "next", "back" and "switch' are the same and they are related to each other; but the business of these behaviors can be different totally. That is where the pattern "Chain of Responsibility" can be applied.
Step by Step Building It! In this simple project, I …

Avoiding Time-Wasting Pitfalls in Agile Estimation

If you do Scrum at work, you might be very familiar to the estimation in Planning 1. My PO has once complained to my team that why it took too long for estimating just a story. Wasting time results in the planning timebox is violated.


I give you some advice from my experience:
Estimation is estimation, not measure. When you read some requirements, you see some risks but you actually don't know how complicated it will be.  Don't try to influence the others by explaining how to do it in too detail. Just keep in mind that you know the business domain pertaining to customer needs and estimate how much effort you will spend for it. The effort should be compared to your baseline one that you use for a simple requirement.

The bottom line is we do "relative estimation", not absolute estimation. For example, you are asked to estimate the height of a building. Basically, you just need to answer "how many times higher is the build than your height"; you don't ha…

Attribute 'for' of label component with id xxxx is not defined

I got the warning in the log file when I have used the tag <h:outputLabel> without attribute "for" in xhtml file. It was really polluting my server log files.

The logged information actually makes sense anyway! We could find an answer as the following:

"Having h:outputLabel without a "for" attribute is meaningless. If you are not attaching the label, you should be using h:outputText instead of h:outputLabel."

However, these solutions are not possible just for my situation. Instead of using h:outputText for only displaying text, my team has used h:outputLabel too many places. We were nearly in our release time (next day) so it is quite risky and takes much efforts if we try to correct it. Because the style (with CSS) is already done with h:ouputLabel. The alternative by adding attribute "for" the existing h:outputLabel is not reasonable either. I really need to find another solution.
Fortunately, I came across a way if I change to use p:out…

The power of acceptance test

User Story is the place PO gives his ideas about features so that developers are able to know what requirements are. Acceptance tests are these show the most valuable things of the features represented by some specific cases. Usually PO defines them, but not always. Therefore, refining existing acceptance tests – even defining new ones that cover all features of the User Story must be a worth task.

If we understand what we are going to do, we can complete it by 50% I have worked with some members those just start implementing the features one by one and from top to down of the User Story description. Be honest, I am the one used to be. What a risky approach! Because it might meet a case that is very easy to miss requirements or needs to re-work after finding any misunderstood things.

I have also worked with some members those accept spending a long time to clarify the User Story. Reading carefully of whole User Story by defining acceptance tests makes us more confident. Having an ove…

Retrospective with Sailboat

Have you ever got bored with the Retrospective meeting? I have, sometime. Most of the times, this meeting just goes traditionally by answering three questions: "What good things have we done? What bad things have we done? And, what actions should we improve?" Ever and ever again! My team found a way to make it a little bit more exciting. The idea is that each member - not only our Scrum Master - will become a host. If a meeting is hosted by a memeber, the next meeting will be hold by another one.

Yeah, I used "Sailboat" pattern in my turn. So, I just want to share with you guys how it was.
I started the meeting by telling a short story that I hoped everyone in my team could recall the meaning behind of Retrospective meetings:
There is a group of people trying pick up trash in a park. At the first look, the park seem not to have a lot of trash because they are spread out all over the place. However, these people continuously found trash when they started. They kept …

Updates to the Scrum Guide - The 5 Scrum Values

This article is available at blog.scrum.org, here I just quote my favorite points and give my comment at the end of this post.

Ken Schwaber and Jeff Sutherland, the creators of Scrum delivered a webinar on their latest update to the Scrum Guide.  The update was a simple one, adding the 5 values of Scrum to the Guide:


These values sound easy? Well, there are many misunderstandings and common problems when applying these values. Here are some example:

Value Misunderstanding Getting the value right Commitment Committing to something that you don’t understand because you are told to by your boss. Committing yourself to the team and Sprint Goal. Focus Focusing on keeping the customer happy Being focused on the sprint and its goal. Openness Telling everyone everything about all your work Highlighting when you have challenges and problems that are stopping you from success Respect Thinking you are helping the team by being a hero Helping people to learn the things that you are good at and not judging the t…

Styling Sort Icons Using Font Awesome for Primefaces' Data Table

So far, Primefaces has used image sprites for displaying the sort icons. This leads to a problem if we want to make a different style for these icons; for example, I would make the icon "arrow up" more blurry at the first time the table loading because I want to highlight the icon "arrow down". I found a way that I can replace these icons with Font Awesome icons.


We will use "CSS Pseudo-classes" to achieve it. The hardest thing here is that we should handle displaying icons in different cases. There is a case both "arrow up" and "arrow down" showing and other case is only one of these icons is shown.

.ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s { background-image: none; margin-left: 5px; font-size: 1.1666em; position: relative; } .ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s:not(.ui-icon-triangle-1-s)::before { content: "\f106"; font-family: "FontAwesome"; position: absolut…

Meaningful Names - Code Review Checklist with Example

"Names are everywhere in software". "The hardest thing about choosing good names is that it requires good descriptive skills"[1]. In my previous post, I emphasized that we should take care our code, so now let's start with naming.

Issue Original code Revised code Reveals nothing int d; //elapsed time in days int elapsedTimeInDays; Difficult to understand public List<Cell> getThem()
public List<Cell> getFlaggedCells()
Specific to programmers accountList accounts

If We Want to Go Fast, We Need to Go Well

Have you ever thought that we won't need to code anymore because programs might be generated from specification? The answer can be yes or no; there is still arguing about it.

The programming language is more and more closed to the requirements. The starting is from a very low level as Assembly to a very high level like Python. However, it doesn't make much sense when saying that we will eliminate coding. For me, we currently still need to express our ideas in exact words that tells the machine what we want. Otherwise, I hope in the future the machine is intelligent enough to understand our requirements directly from our words. ;)

Take a look at the famous quote of Robert C.Martin about what I mentioned above:

"Remember that code is really the language in which we ultimately express the requirements. We may create languages that are closer to the requirements. We may create tools that help us parse and assemble those requirements into formal structures. But we will never e…

Changing source code at run-time with Service Locator pattern

I have a service to get some data but the result can be different basing on where the implementation is. Technically, I have two or more concrete implementation of an interface and I am able to switch using these concrete classes at run-time. That means I have a place to configure it without re-deploying the application. In order to overcome this issue, I use Service Locator design pattern and here I only care about two advantages below:
Encapsulating the specific implementation, we just declare the name and don't care about the implementation of the service.Changing the implementation at run-time.


Client: an object that invokes the services via Service Locator Business services: services that is used by Client.

My impression of Google I/O 2016

I have not yet had a chance to attend this event but I just watched it on Youtube as usual. :)
Google Assistant You might be very familiar to Google Now if you're Android fan. I saw that Google Assistant is like an upgrade to Google Now. It looks smarter because we are able to make a conversation with Google rather than just saying "Ok Google" and getting the tasks done as Google Now. That means Google Assistant can understand our personal words in our contexts.

For example:
I: Who is Google CEO? Google: Sundar Pichai I: Show me his awards  => Here I don't need to say "Show me Sundar Pichai awards", because I don't know to pronounce his name correctly. :)
I am thinking about that we can compare Google Assistant to Siri of Apple. Google Home At Google I/O 2015 last year, Sundar mentioned about working on a exciting project with Internet of Things and I think Google Home is a result. Working with Google Assistant, Google home is a very smart and modern devi…