Monday, December 2, 2013

The Check List for Documenting Software Architecture.

                       Software architecture has emerged as an important sub-discipline of software engineering,particularly in the realm of large system development. While there is no universal definition of software architecture, there is no shortage of them.

However What those definitions have in common is their emphasis on architecture as a description of a system as a sum of smaller parts, and how those parts relate to and cooperate with each other to perform the work of the system. Architecture gives us intellectual control over the very complex by allowing us to substitute the complex with a set of interacting pieces, each one of which is substantially simpler than the whole.






Why we need Software Architecture in a document ?


Professor Dijk-stra’s consideration for the reader reflects his classic manners, but it also gives us a new and useful concept of the effort associated with a document. Usually we just count how long it takes to write. Dijkstra taught us to be concerned with how long it takes to use.

  • The goal of documenting an architecture is to write it down so that others can successfully use it, maintain it, and build a system from it. The blue-print for developing a Software System.
  • Documentation exists to further architecture’s uses as a means of education, as a vehicle for communication among stakeholders, and as the basis for analysis.
  • Documenting an architecture is a matter of documenting the relevant views and then adding documentation that applies to more than one view.
  • Documentation should pay for itself by making development activities less costly.


Check List( 7 Rules)  for documenting the Software Architecture.

1.  Write documentation from the Reader's point of view.

  • Find out who your readers are, what they know, and what they expect from the  document. The best way to get to know your stakeholder is to have a informal chat and make sure not doing any wrong assumptions on them.
  • Don't write the content as  it easy for you or as it come to your mind, make sure you get the big picture of the overall document. You can break down the document into the sections and make sure relevant sections provide answers to some of architectural concerns.

  • Avoid specialized terms and jargon, since reader may not be sharing same terms as you do, so add a glossary to define your terms.

  • Avoid overuse of acronyms , if your phrase is not used many times in the doc or short in length then better to use as it is.

2. Avoid Unnecessary repetition.

  • Need to make sure same content is not repeated on different places , which will put reader into trouble when when you had updated the content in one place and forgot to change at all other places. So the best way to handle this, keep common content referenced by a reference number  or using hyper link ( in a soft copy ).

3. Avoid Ambiguity
Ambiguity occurs when documentation can be interpreted in more than one way and at least one of those ways is incorrect.


  • Avoid needless repetition ( as in rule 2 above ) 
  • Use well defined notations and precise semantics as much as possible.
  • The ubiquitous box-and-line diagrams that people always draw on whiteboards are one of the greatest sources of ambiguity in architecture documentation , if you use such make sure you have notation to explain what it means for. Simple arrow can represent many things like, calling the other module , data flow  etc.

4. Use standard Organisation/Template.
  • It helps the reader navigate the document and find specific information quickly
  • The template already provides an outline of the important topics to cover and  helps the document writer plan and organize the contents.

  • It reveals what work remains to be done by the number of sections labeled “TBD”

5. Record rationale
  • You should record why you made them the way you did. You should also record the important or most likely alternatives you rejected and state why
  • You will find yourself revisiting the same arguments and wondering why you didn’t take another path.

6. Keep Documentation Current but Not too Current.


  • Documentation that is somehow inadequate to answer the current question needs to be fixed.
  • Updating it and then referring the questioner to it will deliver a strong message that the documentation is the final, authoritative source for information.
  • No need to keep updating the document on every decision made instantly, rather give it a proper time to go through final review /approval and then add it as the final update to the document.

7. Review Documentation for the Fitness of  purpose.


  • Before a document is released, have it reviewed by representatives of the community or communities for which it was written.Only the intended users of a document will be able to tell you whether it contains the right information.

Saturday, June 29, 2013

Java EE7 and Its Evaluatioon


After more than three years with JEE 6 , The latest iteration of java enterprise edition has landed, this version includes improvements and tweaks in different areas of Java EE, specially this version includes introduction of HTML 5. As java developers , we will able to more focus on writing our business logic than writing boilerplate code, have better support for the latest Web applications and frameworks, and gain access to enhanced scalability and richer, simpler functionality. New Java EE 7 will
benefit from new features that enable portable batch processing and improved scalability.

Evolution of Java Enterprise Platform
Over 15 years, Java enterprise platform has changed the world on enterprise  solution implementation and developers around the world  has committed to keep the momentum going.



1998 - 2004
Java EE evolved as enterprise application development platform , and main focus was on robustness and ease of development which extended to facilitate multitier server centric applications development, deployments and maintenance.


Features 
  •   Servlet and JSP
  •  EJB , CMP , RMI/IIOP
  •  Java Connector Architecture
  •  Web Services


2005 - 2012

The focus  shifted to increase developer efficiency and introduction of light weight frameworks like Web Profile as subset of  Java EE specification.

Features 
  •    Introduction of annotation.
  •    EJB 3 business component development model
  •    Persistence API
  •    RESTFull Web Services
  •    Web Profile and Managed beans


2013 - Future       
                                  
With increase demand of enterprise solution to be simplified and reusable , next level of Java EE will be moved into cloud (PaaS)support. Java EE8 will be mainly focus on cloud support  and etc.

Features 
  •    HTML 5 support
  •    Java API for Web Socket
  •            Batch Processing support for Java
  •            Concurrency utilities
  •     Native Jason support


Theme of JEE 7
There are 3 major themes of Java EE 7 as shown below.





Delivering HTML5 dynamic, scalable applications
  •    Reduce response time with low latency data exchange using WebSockets
  •    Simplify data parsing for portable applications with standard JSON support
  •    Deliver asynchronous, scalable, high performance RESTful Services and Async Servlets


Increasing developer productivity through simplification and new container services
  •    Simplify application architecture with a cohesive integrated platform
  •    Increase efficiency with reduced boiler-plate code and broader use of annotations
  •    Enhance application portability with standard RESTful web service client support


And meeting the additional demands of the enterprise by adding new enterprise technologies.
  •    Break down batch jobs into manageable chunks for uninterrupted OLTP performance
  •           Easily define multithreaded concurrent tasks for improved scalability
  •    Deliver transactional applications with choice and flexibility

Major 4 features in Java EE 7

1. HTML5 , Web Socket and Client/Server endpoints


  • Java EE7 is mainly focused on HTML5 and its improvements to the spec,  which allows to develop multimedia enriched web applications , support will be via Web Socket and JSON.
  •  Web Socket is a way of two way communication with web app and the remote server in HTTP fashion with bidirectional full-duplex TCP connection.
  •  Annotation makes everything simple
                                @ServerEndpoint  - convert your POJO class to be web socket server
                  @ClientEndpoint  -  convert your POJO  class to be client socket end point.