From JSP to AngularJS

Our team maintained a project that was used a quite old web technology JSP. Our project likes a web portal that can contain some other smaller projects, I called it a module. Now, our customers want to add a new module into it.

We met a problem is the current projects can't be testable and hard to maintain because both the logic and GUI are mixed together by using JSP and JSTL. It was really a messy project structure. Therefore, we didn't want to continue this approach. Testing is very important, as well as a good structure for maintenance. We would like to apply MVC pattern for testable and maintainable ability purpose. Yeah, that was actually time for changes.

Our project structure can't be testable and has poor structure.

We listed out some options:

Refactoring all current modules -- terrible approach, too much efforts, too risky due to a lot of modules.
Using MVC just for the new modules with Servlet for Controller, Java class for Model and JSP for View -- actually, it was impossible for us also because our back-end technology was covered by Axon.ivy, the Servlets were fixed and we didn't want to modify a lot without Axon.ivy's official ways.
Finding a new front-end frameworks that can work with Axon.ivy and apply MVC also -- it seems a best solution, we just should learn a lot by choosing this approach.

We found AngularJS is one of the best choices in that time. we did a quick research and we found AngularJS can help us using MVC. Moreover, we can test with Javascript by using some Javascript test framework, likes Jasmine. We also can setup a Jenkins job for auto-run tests by using Karma.

We used AngularJS and some related technologies to overcome our problems.

That was cool and we decided to go for it.

Comments

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 do...

Strategy Design Pattern

For example, I have a program with an Animal abstract class and two sub-classes Dog and Bird. I want to add new behavior for the class Animal, this is "fly". Now, I face two approaches to solve this issue: 1. Adding an abstract method "fly" into the class Animal. Then, I force the sub-classes should be implemented this method, something like: public abstract class Animal{ //bla bla public abstract void fly(); } public class Bird extends Animal{ //bla bla public void fly(){ System.out.println("Fly high"); } } public class Dog extends Animal{ //bla bla public void fly(){ System.out.println("Cant fly"); } } 2. Creating an interface with method "fly" inside. The same issue to an abstract class, I force the classes these implement this interface should have a method "fly" inside: public interface Flyable{ public void fly(); } public class Bird implements Flyable{ //bla bla public void fly(){ System.out.pr...

What the heck is Meteor DDP?

I was using Meteor for my messenger project. I was so curious about the real time connection. I wanted to know how exactly this mechanism works. In this post, I will go through the DDP Specification, an overview of WebSocket, and a simple demo about how to subscribe a publication of Rocket.Chat (containing a DDP server) from an external webpage. At a glance, I knew that Meteor invented a protocol called DDP which uses for handling real time connection. So then, what is DDP? "DDP (Distributed Data Protocol) is the stateful WebSocket protocol that Meteor uses to communicate between the client and the server." [1] All right! Why does DDP matter? "DDP is a standard way to solve the biggest problem facing client-side JavaScript developers: querying a server-side database, sending the results down to the client, and then pushing changes to the client whenever anything changes in the database" . [2] In order to understand deeply the protocol, I decided ...

Math fundamentals and Katex

It was really tough for me to understand many articles about data science due to the requirements of understanding mathematics (especially linear algebra). I’ve started to gain some basic knowledges about Math by reading a book first. The great tool Typora and stackedit with supporting Katex syntax simply helps me to display Math-related symbols. Let’s start! The fundamental ideas of mathematics: “doing math” with numbers and functions. Linear algebra: “doing math” with vectors and linear transformations. 1. Solving equations Solving equations means finding the value of the unknown in the equation. To find the solution, we must break the problem down into simpler steps. E.g: x 2 − 4 = 4 5 x 2 − 4 + 4 = 4 5 + 4 x 2 = 4 9 x = 4 9 ∣ x ∣ = 7 x = 7 or x = − 7 \begin{aligned} x^2 - 4 &= 45\\ x^2 - 4 + 4 &= 45 + 4\\ x^2 &= 49\\ \sqrt{x}&=\sqrt{49}\\ |x| &= 7\\ x=7 &\text{ or } x=-7 \end{aligned} x 2 − 4 x 2 − 4 + 4 x 2 x ∣ x ∣ x = 7 = 4 5 = 4 ...

MS SQL Server Views

"Creates a virtual table whose contents (columns and rows) are defined by a query. Use this statement to create a view of the data in one or more tables in the database. For example, a view can be used for the following purposes: - To focus, simplify, and customize the perception each user has of the database. - As a security mechanism by allowing users to access data through the view, without granting the users permissions to directly access the underlying base tables. - To provide a backward compatible interface to emulate a table whose schema has changed." [1] Beside that, our team used view in order to improve the performance of our web apps when a database has a very complicated relationship between its tables by using ORM Frameworks such as Hibernate. Example code: --create CREATE VIEW placeholders AS SELECT EMPKEY AS empkey, CONNUMB AS connumb, EMPNBR AS empNbr, ACEEMPN AS empFirstName, ACEEMPFN AS empLastName, EMPNAM AS empFullName, ...

vhandit

Search This Blog