A little Architecture Lesson

I found this blogpost:

http://blog.cleancoder.com/uncle-bob/2016/01/04/ALittleArchitecture.html

I think I still have a lot to learn.

Google App Engine - First try

Introduction

I own an Internet-enabled digital scale for weighing myself and measuring my impedance.

Architecture

Functional Requirements (FR):

• I wish to store a backup of my scale measurements, for my own purposes
• however, scale measurements must continue to be reported to the official website

I have several Non-Functional Requirements (NFR):

1. needs to use Java (because that's what I do)
2. the scale receiver uses a simple unencrypted proprietary protocol
3. the program receiving data from the scale receiver can handle raw sockets (related to previous point)
4. must scale easily
5. must not cost any money (until a certain threshold of users is reached, obviously)
6. must provide decent monitoring
7. needs to have an extremely low amount of maintenance
8. must be able to easily create/upgrade/extend the part that uses those measurements for stuff, without disrupting the core functionality of receiving measurements
9. needs to have the Cool Tech Factor™

These dictate which kind of architecture to use:

1. Google App Engine (NFR 1, 4, 5, 6, 7, 8 but fails 2 and 3, definitely allows for NFR 9)
2. a simple socket server, receives measurements, sends them on to Google App Engine and the original website (NFR 2, 3, 5, 7, might fail 4 and 8, but perhaps not if we keep the amount of actual work done by the simple socket server to a minimum, definitely fails NFR 9)

Implementation

The "Daemon³" sends the results to the Google App Engine², using a Java library¹ to make a HTTP POST request.

Example of Use

In the upper-right corner of my blog, my current weight is visible. It is a first example of what is possible.

I am planning on providing, on my blog, a complete graph of my weight over time. Stay tuned.

For the "Daemon" in the picture, that is the socketproxy server I made first. See [3].

References

[1] Apache HTTP Components

https://hc.apache.org/

[2] Google App Engine

https://developers.google.com/appengine

[3] SocketProxy Server

http://randomthoughtsonjavaprogramming.blogspot.nl/2014/03/socketproxyserver.html

1Z0-807 Java EE 6 Enterprise Architect Certified Master Exam

follow-up of [2]

Pfew! Made it! Woohoo! I had answered 73% of questions correctly, and I needed 71%. I should've studied more.

It is Multiple-Choice, and some of the wrong possible answers are really quite close to correct.

Then again, who has to answer a Architectural Question in their business careers in less than 2.5 minutes on average, really?

On to the next step, the Assignment!!

The exam

Most of the exam questions were regarding business use cases.

The exam questions can be broadly separated into three distinct categories:

use cases

of imaginary companies seeking to change/re-evaluate (a part of) their current outdated infrastructure in some fashion

questions on design patterns

when to use them, what their characteristics are, etc. ^*)

questions on JEE technologies

when would you apply which technologies, given some Non-Functional Requirements (NFR)

*) Seems the books "Core J2EE Patterns", "Real World Java EE Patterns: Rethinking Best Practices" and "Design Patterns: Elements of Reusable Object-Oriented Software" really did help, and were fascinating reads in and of themselves.

References

[1] 1Z0-807 Java EE 6 Enterprise Architect Certified Master Exam

http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-807

[2] Architect Enterprise Applications with Java EE - Course

http://randomthoughtsonjavaprogramming.blogspot.nl/2013/09/architect-enterprise-applications-with.html

Architect Enterprise Applications with Java EE - Course

I had the opportunity to attend the Oracle course on "Architect Enterprise Applications with Java EE"^[1] from Monday 09/09/2013 to Friday 13/09/2013. (after forking over a big sack of money)

The Course does have a number of Lab exercises, mostly based on UML or open questions (that created several discussions, which I enjoyed immensely). UML diagrams were drawn using UMLet^[3].

I took the course as I wish to prepare for the 'Oracle Certified Master, Java EE 6 Enterprise Architect' certification.

This is the first step in the Certification Process ^[2].

I did receive some very interesting Course material along with it. However, it's been licensed to me specifically. (I could let you read it, but then I would have to kill you. Oracle licensing rules say so.)

References

[1] Architect Enterprise Applications with Java EE

http://education.oracle.com/pls/web_prod-plq-dad/ou_product_category.getAllProductsPage

[2] Oracle Certified Master, Java EE 6 Enterprise Architect

http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=458&get_params=p_track_id:OCMJEE6EA

[3] UMLet

http://www.umlet.com/