An Agile Architect's Notes

2011-12-22T14:52:00.001-08:00

Java Vs C performance comparison

2009-09-08T21:09:00.000-07:00

When Java was gaining prominence a few years ago, the debate around performance of applications built using Java/C/C++ used to happen quite often. However when Java took over the world, the performance debate nearly died down even though C/C++ applications play fairly well when it comes to performance. With the above context of performance, I recently came across the article from Azul systems comparing the instances where Java applications fair well as compared to C/C++ and vice versa. Read the complete article here

TSVN Icon Overlays does not appear on explorer

2009-02-03T05:07:00.000-08:00

Tortoise SVN behaves sometimes pretty weird but not with respect to functionality but with display. Recently while playing with TSVN 1.5.5 and found that it is not displaying icons to show the file/folder status. I am running it on WinXP with sufficient memory on it.

In fact, displaying the status through Icon overlays is one of the key features with TSVN. After googling around for sometime and trying various options, zeroed down on one. The solution that worked for me included changing the "Cache status" from "Default" to "Shell".

Following image would show the new status. One can access Cache status by right clicking on the windows explorer --> Tortoise SVN --> Settings --> Icon Overlays

Subversion Installation - Step by Step Tutorial

2009-01-15T08:22:00.000-08:00

Recently I played around installing SVN 1.5.1 with Apache 2.2.

Following paragraph provides detailed steps
1. Install Apache 2.2
2. During subversion installation ensure that you choose the proper Binding ie. Apache 2.2 (in our case)
3. Using the windows explorer, go to the installation directory of Subversion (usually c:\program files\Subversion) and find the files /httpd/mod_dav_svn.so and mod_authz_svn.so. Copy these files to the Apache modules directory (usually c:\program files\apache group\apache2\modules ).
4. Copy the file /bin/libdb*.dll and /bin/intl3_svn.dll from the Subversion installation directory to the Apache bin directory.
5. Edit Apache's configuration file (usually C:\Program Files\Apache Group\Apache2\conf\httpd.conf) with a text editor such as Notepad and make the following changes:

Uncomment (remove the '#' mark) the following lines:
#LoadModule dav_fs_module modules/mod_dav_fs.so
#LoadModule dav_module modules/mod_dav.so
Add the following two lines to the end of the LoadModule section.
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so
6. Now you are ready to check out the files. Create a local working folder and do an initial check out. Create the following folders trunk, branches and tags. Check in these folders into the repository. The main directories that you need to add to repository for the first time should go into trunk folder.

Whenever one wants to tag the code, you can do so by adding tags/ to the repository URL.

Configuration
Now you have set up Apache and Subversion, but Apache doesn't know how to handle Subversion clients like TortoiseSVN yet. To get Apache to know which URL will be used for Subversion repositories you have to edit the Apache configuration file (usually located in c:\program files\apache group\apache2\conf\httpd.conf) with any text editor you like (e.g. Notepad):
1. At the end of the config file add the following lines:

DAV svn
SVNListParentPath on
SVNParentPath D:\SVN
#SVNIndexXSLT "/svnindex.xsl"
AuthType Basic
AuthName "Subversion repositories"
AuthUserFile passwd
#AuthzSVNAccessFile svnaccessfile
Require valid-user

This configures Apache so that all your Subversion repositories are physically located below D:\SVN (Say). The repositories are served to the outside world from the URL: http://MyServer/svn/ . Access is restricted to known users/passwords listed in the passwd file.

Ensure that you create the repository at D:\SVN by using the following command:
svnadmin create D:\SVN
The above command assumes that there is a folder called “SVN” under D:\

2. To create the passwd file, open the command prompt (DOS-Box) again, change to the apache2 folder (usually c:\program files\apache group\apache2) and create the file by entering
3. bin\htpasswd -c passwd
This will create a file with the name passwd which is used for authentication. Additional users can be added with
bin\htpasswd passwd
4. Restart the Apache service again.
You can test your configuration by using: http://localhost:8090/svn/
It assumes that Apache Server is running on 8090 port. In my case, I had something else running on 80, so configured Apache server to run on 8090

Following two sites gives wealth of information about "Branching"
http://tortoisesvn.net/docs/release/TortoiseSVN_en/tsvn-dug-branchtag.html

http://drc-dev.ohiolink.edu/wiki/TortoiseSVNHowTo

Web 3.0 ?

2008-08-02T09:47:00.001-07:00

Many of are still grappling with Web 2.0 and most of the traditional companies are still in Web 1.0. But this post published on Tech Crunch is already making headway into Web 3.0.

We need to stop walking fast and need to run to catch up with this new way of life.

Can software component creation be industrialized ?

2008-06-21T21:46:00.001-07:00

One of the best examples of industrialization in this century includes car manufacturing, and invention of assembly lines. Each parts of the car gets manufactured somewhere else and finally gets assembled at one place. The parts are made with such a perfection that even robots can put together various parts in no time. You might be wondering, yeah I know this and everybody knows this fact, how is this related to this software architecture blog ? Okay, here is what I wanted to ask, can the software be developed in a similar manner as a car gets manufactured ? i.e. various components can be designed and developed at various places, and shipped to one location. Some automated tools can in turn assemble these components to build an application. Finally a final test can be done by the QA team before releasing the product. I believe it is difficult to implement this idea in a software industry keeping our current understanding and knowledge in mind, however it is not impossible. Here is an article that provides more insight into the topic I am discussing.

Loosely coupled, reusable and Replaceable components

2008-06-21T08:58:00.001-07:00

I am sure as software developers we know the importance of designing and developing reusable and loosely coupled components. Recently in the XP discussion forum I came across a discussion on the topic of "Building Agile applications using replaceable components". It drew my attention and followed the thread to understand where it was heading. Basically the author challenges the basic assumption behind "loosely coupled components". Instead of giving my version of the details, I would let his article speak about the thoughts.

Here are couple of links from the author(Raju's) webpage explaining loosely coupled, replaceable components.

Hierarchy of swappable modules

Loose coupling and SOA

How to build an application using replaceable components

Also this article challenges the assumption that Java could be used to build loosely coupled, replaceable components.

Steps to remember during tradeoff analysis

2008-02-28T02:36:00.001-08:00

It is important for all software architects to be aware of conducting the tradeoff analysis on the "Non Functional Requirements" (NFRs). It is better to have a handy tradeoff guide available during the design phase.
The tradeoff guide could be built either based on one's own experience or by taking help from other architects/resources. It would be good, if the guide covers most of the architecture principles and the non functional requirements (also called -ilities)

I would recommend following steps while doing tradeoff analysis

Understand the customer's requirement and convert it into SMART objective
Prioritize the requirements (NFRs) by having continuous collaboration with the customer
Finally, using the tradeoff analysis guide, recommend the final design and educate the customer about the impact of the design on the priorities.

Open Source is not free

2008-02-27T02:55:00.001-08:00

All of us know that the Open source softwares(OSS) are available free of cost to download, modify, distribute and even sell this to our customers and make money.

Many companies wants to use OSS in their product development/projects thinking that they could save money by choosing OSS. In reality, choosing the right OSS helps companies in saving money, and at the same time the wrong ones would incur cost to them.

Check this article out to know why OSS is not free !!

Premature Optimization and the evil

2008-02-27T01:54:00.001-08:00

Right from the day I have started designing applications, I have been hearing people quoting the famous words,specifically dealing with "performance".

Premature optimization is root of all evil - Sir Tony Hoare (popularized by Donald Knuth)

As we aware, the words like "Premature", "Optimization" and "evil" these are generic terms and open for interpretations with no SMART objective associated with them. Developer to PM to architects, each interprets the above quote in their own way and, sometimes using it to their own advantage as and when needed.

let me share my perspective of the above quote. "Premature optimization" has two important hidden pointers. First one, the "time/period" i.e. how much "premature" is acceptable. The second pointer is "quantity" i.e. how much "optimization" is necessary.

Let me start with the second pointer "Optimization". Optimization of any application could be done at various stages. During the design stage, implementation and pre release. So, what stage is ideal to do performance optimization ? Or, should it be done continuously ?

My experience shows that following steps are needed during performance optimization

performance criteria needs to be well understood at the beginning of the project,
it should be explained to all team members(means testers included)
Good design and coding guidelines(ex: proper use of String Vs StringBuffer, use of sets, hashmaps, etc) around performance needs to be created and taught to the development team
Each component/module needs to be designed to satisfy the ground rule created at the beginning around performance, and excess tuning needs to be avoided.
Check points at regular intervals should be created and performance testing should be done

Summary of my understanding around premature optimization quote is,

Optimizing design,code is a continuous process happening throughout the development cycle.
excess application optimization at the beginning of the project should be avoided

My thoughts mentioned above are also reflected pretty much in this artice, and the author has gone in depth and has given a good explanation around premature optimization.

Patterns to improve performance in J2EE Applications

2008-02-22T04:05:00.001-08:00

Precisejava provides a list of patterns that would improve performance in J2EE applications. The author explains each of the patterns with good examples and reason behind improved performance.

Amazon web services goes down

2008-02-16T15:38:00.000-08:00

It is unbelievable but true ! Amazon Web Services suffered a major outage this morning, affecting the thousands of Websites that rely on its storage (S3) and cloud computing (EC2) services. Here is the whole story

When I first got introduced to S3 and saw the demo of the concept with the high availability architecture behind S3, I felt this is the thing of the future. Now, I am thinking, we still have a long way to go while building highly scalable and available applications.

101 design pattern tips

2008-02-07T21:30:00.000-08:00

This site has a consolidated list of 101 design patterns. The author has put a lot of effort in organizing the patterns into different groups (GOF + others). Upon clicking on each of the patterns, it provides the motivation, mechanics with an example.

Encapsulation need not be informaton hiding

2008-01-31T22:45:00.000-08:00

Encapsulation and information hiding are the most mis-used word while describing a component based architecture. Encapsulation refers to the bundling of data with the methods that operate on that data. Often that definition is misconstrued to mean that the data is somehow hidden. In Java, one could have encapsulated data that is not hidden at all.

More information about why Encapsulation is not information hiding is explained here very clearly.

On a similar note, following principles go hand in hand very closely:

1. Encapsulation
2. Modular design
3. Information hiding
4. Isolation
5. Separation of concerns

Service Oriented Network Architecture

2007-09-24T01:33:00.000-07:00

Here is a very informative article on Service oriented architecture principles and SO Network Architecture

Biggest mistakes in Web design

2007-09-03T06:56:00.000-07:00

If we visit any website, and if we can stay for more than 10 seconds then chances of revisiting the same website is more, else we may not visit that website again. What makes us to stay or leave with a website is decide by the usability experts of the website. If the users cannot get what they want in a website in 10 seconds, they would leave. If you want to test this, check out your own browsing habits ...

here is a informative website pointing out various things to keep in mind while designing websites. Vincent seems to have done extensive research on usability and keeps the website live.

Step by Step procedure to install Tomcat 6

2007-08-28T04:28:00.001-07:00

This is the first website that I have come across so far, providing detailed installation instruction on Apache Tomcat 6

Ola Bini in Bangalore

2007-08-28T01:15:00.000-07:00

Ola Bini core committer of JRuby is in Bangalore. Thoughtworks would be hosting this event.

Architecture lingo

2007-08-27T01:48:00.000-07:00

Being in the architect's world, I keep hearing so many different types of Architecture. I thought I would list them here and keep updating this post as and when I hear a new type . Many of the listed architectures could be related to one another, subsets, supersets of each other. My intention is to just list them without worrying how they are related to each other !!

(Not in any specific order)
1. Business Architecture (goes hand in hand with Enterprise Architecture)
2. Application Architecture
3. Information Architecture/Information Management Architecture
4. Technical Architecture
5. Enterprise Architecture
6. Solution Architecture
7. Data Architecture
8. System Architecture
9. Infrastructure Architecture
10. Development Architecture
11. Execution Architecture
12. Operations Architecture
13. Population Architecture (related with DataWearhousing)

Manipulating the data in temporary tables

2007-08-26T22:20:00.000-07:00

The question asked by Sophie was "Can you use a Stored Procedure to open a table and copy data to a sort of virtual table (or a records set) so that you can change the values with and not affect the actual data in the actual table. And then return the results of the virtual table? Thanks!"

The solution, Yes it is possible to do it is explained in detail here

History of Javascript and overview of Client and Server Side scripts

2007-08-23T21:54:00.000-07:00

This article provides the history of javascript and the different types(client side, server side and core)

Web trends in 2007

2007-07-21T20:56:00.000-07:00

Here is a cool and cute image depicting web trends in 2007. Looks like Web 2.0 would become even more popular in coming months !!

Scaling without a Database

2007-04-17T21:43:00.001-07:00

Found this nice article on "Scaling web application without a Database". Really thought provoking !!

CORBA Vs Web Services

2007-02-27T00:53:00.000-08:00

I came across this nice article bringing out the clear details about CORBA and Web Services. One of the best articles that I came across so far on this topic

Testing Private Methods

2007-02-12T00:03:00.000-08:00

There are a lot of discussion going on in test infected community on how to go about testing private methods. One of the suggested approach is to nest a static test class within the production class. This package level access static class can be called from our testing class, which in turn would call the private methods.

I strongly disagree with this method. Couple of reasons:

1. We would be adding extra code in the production code.
2. It might add more cost to the customer

First we have to understand that, the reason why we want to test the application is to ensure that our application works well and conforms to certain requirements given by the customer. We need to weigh the cost of maintaining these tests also. Customer pays money for the product, and the testing is the extra burden we are putting on the customer to ensure we deliver something right.

When we deliver the nested class with the production code, we are in fact sending something that was not requested by the customer. This class in turn might introduce its own defect.

Let us take a simple analogy, process of car manufacturing. Consider that the testing team inserts a device into the car during car manufacturing. This device would ensure that they can test "engine temperature" accurately. This device would go with the car to the customer also. Problem here is, we may not know the impact of this device on mileage of the car !!. Even though it has made the lives of developers easy, we are charging the customer for this device too.

I strongly feel that, if we want to test something, we should do so without touching the production code.

Document style Vs RPC

2007-02-03T17:38:00.000-08:00

Here is a good introduction bringing out the difference between RPC Vs document style web services

Distributed SOA

2007-01-09T18:52:00.000-08:00

Nice article on distributed SOA

It's hard to turn anywhere today without seeing something about
service-oriented architecture, or SOA, and a debate about the "right"
way to do it. That's not surprising, I guess, since every new
computing trend generates debate and every vendor tries to promote
their technology as the right technology – the right product – that
will allow customers to take the most advantage of a new approach.
It's a scramble as vendors try to aggressively reposition their
existing product suites to take advantage of customer interest in a
hot IT trend. It's unfortunate, though, because this behavior often
creates a lot of confusion and potential disillusionment, as promises
made often do not turn into promises kept and technology solutions
sold as appropriate for SOA may turn out not to be.

To set the right perspective on this, it's important to note that SOA
is, by definition, distributed. The purpose of a service is to
communicate remotely with another service, typically to share data.
The purpose of an SOA is to change the approach of IT from building
bespoke, monolithic applications to building applications that are
developed and integrated more and more using assets from a collection
of shared, reusable functionality, i.e. services.

A distributed SOA infrastructure represents the easiest way to deploy
and consume shared, reusable services, facilitating incremental
adoption (both economically and technically) and enable greater
deployment flexibility, adaptability and maintainability (e.g., single
services can be certified for update more easily than an entire
application) .

Unfortunately, centralized approaches to SOA infrastructure continue
to be developed and proposed. Vendors will go to great lengths to
convince the technology buying public that what they're offering is
already SOA compliant, always was, always will be and was truly
designed from the beginning to facilitate their customers' move to
SOA, no matter whether it was originally designed to be a JEE
application server or EAI system.

In other words, vendors taking an opposing view to distributed SOA
infrastructure often do so because that's the nature of the software
infrastructure they already have. A refried EAI hub or JEE-based stack
or any other solution that requires request messages to be passed
through a central control point, cannot be considered truly
distributed since all access to services must be routed through a
central hub or a server. This centralized approach to SOA adds cost,
limits reuse, reduces flexibility and introduces a potentially
expensive bottleneck. In the worst case it could even negate the
reasons for moving to SOA in the first place. People are bound to be
disappointed if the flexibility of their SOA infrastructure does not
meet their requirements.

One only has to look to the World Wide Web to see an example of a
distributed application that very successfully meets its users'
requirements. The Web is the largest distributed application ever
built and it's distributed by nature, like an SOA should be. When you
use a browser to click on a link to a URL, your request is not routed
through some kind of central controlling authority deployed in a
server or a hub. Your request goes directly from your browser to the
Web server hosting the page you have requested. This approach works
fine for the Web and it also works fine for an enterprise's SOA. Web
endpoints can be updated individually without breaking clients,
affecting other sites or requiring any update to a central hub or
server, since requests do not have to pass through one in the first
place. A good SOA infrastructure also supports these capabilities.

Fortunately, an infrastructure solution exists that embraces the
distributed nature of SOA. The distributed approach to SOA
infrastructure uses smart endpoints that service enable applications
and allow them to find and directly communicate with other services.
Enterprise qualities of service, such as high availability or advanced
security, can also be included in the endpoints to preserve the
capabilities upon which existing mission critical applications rely.
Distributed SOA infrastructure is about creating an IT environment
that is platform neutral, standards-based and highly flexible, so that
it can respond better to an ever-changing technology and business
landscape. A distributed SOA environment is therefore better able to
support the technical and economic requirements of an SOA based
application. Finally, a distributed approach to SOA infrastructure
allows you to move at your own pace, deploying services one or two at
a time, adding features such as orchestration, registry/repository ,
management and so on as needed and not before.

I'm not saying that EAI systems, hub and spoke based applications or
JEE server centric approaches to SOA infrastructure are all bad or
wrong. Many times existing corporate application functionality depends
upon one or more of these implementation styles. All I'm saying is
that a good SOA infrastructure shouldn't constrain your design options
to what any one of these things can do – in fact a good SOA
infrastructure embraces and includes them among the collection of
reusable service assets.

A parallel between the benefits of distributed SOA and the airline
industry can be seen in the way in which the low-cost operators are
challenging the established carriers. The approach of the established
operators is based on an expensive hub and spoke model that funnels
passengers through a small number of dedicated travel hubs. Large
planes that cost more to operate, fly from spoke airport to hub
airport, where passengers are processed for further travel to their
final destinations. In this model the planes cost more to operate and
airport facility charges are higher. With the rise of low-cost
airlines, which operate on a more distributed, point-to-point model
(smaller planes directly flying to smaller airports), the airlines
that are tied to the traditional hub model are taking a significant
financial hit.

SOA customers do not need more of the same old bloated and expensive
software stacks. Customers need better software specifically designed
for the requirements represented by the SOA trend – to improve the way
in which existing (and new) IT functional assets are provide to
applications. SOA designs need a good way to create and deploy
reusable services that can be called upon simply and directly when and
where needed. Customers need low cost options that allow them to start
small with incremental adoption, using point-to-point communication
solutions that avoid expensive new servers and hubs, adding quality of
service and other features as required. In short, they need SOA
infrastructure that really meets the inherently distributed nature of
an SOA.

You can read the above article here

Socio-Political and Commercial aspect of WS/SOA

2006-12-11T00:51:00.000-08:00

Nice article and a good retrospective.

http://atownley.org/2006/12/socio-political-and-commercial-motivations-for-ws/

Things to know about SOAP before using it - Very funny though

2006-12-02T08:30:00.000-08:00

Here is the most admired post, put together nicely about what SOAP is all about !! Don't hate me if you are a SOAP proponent.

RMI, CORBA and DCOM

2006-11-23T10:47:00.000-08:00

Gregg Wonderly brings out a clear distinction among RMI, CORBA and DCOM usage in one of the tech discussion forums:

I really find it interesting that people continue to bash RMI as something to
put in the same space as CORBA and DCOM. Clearly people have used RMI in much
different/worse systems than I. Based on some of the arguments we've had here,
it seems that the biggest problems people have had with RMI are based on
misunderstandings of the technology and hence misuse of the features. A lot of
people seem to have just made every object extends UnicastRemoteObject, or used
that class to export everything, instead of looking closer and granularity. The
other falling off point is serialVersionUID and versioning overall.

One of the key things about the RMI programming model is that version #1, had
many limitations. Version #2 is present in the Jini platform, created by the
engineers who were part of the CORBA system design and development as well as
RMI. So, they know all of the issues that people waved in their faces over the
years.

The predominate arguments against RMI are always based on "granularity". With
RMI programming, you can design systems that pass big objects, no objects, small
objects, lots of text, or whatever you want. What Jini gives you in an RMI
programming model, is the ability to (with published specs and standards), plug
in any endpoint or invocation technology that you need. Thus, you can take
advantage of all the features of the Jini platform while still providing outward
interfaces using other technologies such as the web or WS-*.

CORBA is a invocation layer technology. DCOM is an operating system specific
invocation layer technology. RMI might be considered an invocation layer
technology. But, it is actually a programming model which includes something
much larger and that's mobile code. Jini expands the RMI programming model with
more features and provides services that use the underlying technologies to
really expand the possibilities.

Lumping RMI in with CORBA and DCOM, I think, really hides the power of what is
available in that programming model. In particular versioning is greatly easier
to deal with when you can exploit mobile code to allow clients to continue to
see an old version of the interface while the implementation is actually much
different. Providing this level of flexibility is what makes it possible to
grow a service with more features and still maintain backward compatibility.

Google-Maps is a great example of the use of mobile code for version control. I
have old google-maps which use old versions of their interface. I haven't had
to convert those to the new system because I download mobile javascript code
that manages that issue for me.

At some point, they might retire that support and I'll have to switch. But, the
point is that there's not an instantaneous moment where I have to be compatible
just so that they can move on to create a better system. They can do it
continuously.

Duties of chief Software Architect

2006-11-10T17:32:00.000-08:00

My recent post on duites of Chief software architect is availble here

Developer Or Architect ?

2006-10-06T13:51:00.000-07:00

I stumbled across this nice article trying to define developer and architect !!

Microsoft launches Architect Certification Program

2006-10-05T10:36:00.000-07:00

Being a Sun Certified Enterprise Architect, I am aware of very few certifications available in the market. I went through the criteria needed to get Microsoft Certified Architect(MCA) program and looks interesting.

Web Development Directory structure

2006-07-10T03:34:00.000-07:00

We have started the new web development and I was discussing about the directory structures with the leads. Initially we had created the directory structure based on technology. I would like to call that as "Technology based directory structure". Recently while we were reviewing one of the open source product, we found that there directory structure is based on "Requirements/Features". Combining the above two we came out with Requirements-->Technology directory structure.

Examples:
Technology based directory structure:
Service
|___ api
|___ impl
|___ dao

Feature driven Directory structure:
Service
|___ usermanagement
| |_ api
| |_ impl
| |_ dao
|___ groupmanagement
|_ api
|_ impl
|_ dao

Java Heap and Windows Operating System

2006-07-01T06:01:00.000-07:00

Today we were trying to deploy confluence integrated with Valtech cockpit on production. The result was an eye opener. Thanks to the confluence which consumes enough memory to push the heapsize to the limit.

As we were doing a test integration, we encountered our first "Out of memory" error within the first 15 minutes. I went back and tweaked the cache parameters within confluence by reducing some of the params like "time to live in memory" and also "number of objects to be in memory". I felts it worked great for next 24 minutes. Even though the "System information" section showed the "heap size" being used only 83%. Suddenly it crashed by throwing "Out of memory" exception.

This tweaking continued until we were able to make it work for next 45 minutes and, we felt this does not make sense to fight without proper information in place about the caches. Anyways, the point is during this struggle to make it work I found this article about setting memory size and its relation with the operating system. I know now, for serious application deployment we should think of linux/solaris or 64 bit systems.

Impact of rewriting the code from scratch

2006-06-20T02:17:00.000-07:00

I was going through Joel's
website, and came across the cardinal law of programming.

It's
harder to read code than to write it

In fact this feels so correct. In the morning, I was trying out ways to
build a javascript function for "inline editing" in one of the custom
grid we have build. I found a sample source code on the website, and when I
opened it, the first thing I felt was this looks like a mess, there are no
proper comments, code is scattered !!! I prefer to just understand some
part of the code and rewrite the whole stuff by myself rather than reusing the
same, which holds good for many developers.

As human beings each one of us are unique, and I believe the same applies for
us when we take the roles of programmers. We want to be unique.

Result: 1. A lot of time gets wasted in rewriting the code

2. Disaster can happen like for Netscape, where it seems they tried rewriting
Netscape 4.0 and it was all over the place, and it took nearly 3 years for them
to put there code together to release Netscape 6.0 (Jumping 5.0), and now they
have lost nearly 80% of the market.

Moral of the story: Never plan to rewrite an entire product from scratch
without clearly analyzing the impact

Testing the class that uses API and not the API itself

2006-06-13T23:28:00.000-07:00

I read the following post from Uncle bob's Website:

It's not enough to write tests for an API you develop, you have to write unit tests for code that uses your API.

When you do, you learn first-hand the hurdles that your users will have to overcome when they try to test their code independently.

Bulletproofing SOA

2006-05-29T23:06:00.000-07:00

I found this nice article on the web on how to bulletproof SOA:

http://news.zdnet.com/2100-9593_22-6076996.html?tag=zdnn.alert

SOA 2.0 - Moving towards Event driven architecture

2006-05-25T00:15:00.000-07:00

Here is an article about future of SOA 1 i.e. SOA 2.0

"SOA 2.0 is the term that we're using to talk about the combination
of service-oriented architecture and event-driven architecture," said
Steve Harris, vice president of Oracle Fusion middleware.

The term, SOA 2.0, also is being championed by Gartner's Yefim Natis,
a vice president and distinguished analyst at the firm. Contacted by
telephone, Natis stressed event-driven architecture as the main
distinction between SOA 2.0 and the first, client-server driven
iteration of SOA.

"SOA as we know it today deals with a client-server relationship
between software modules," with services being subroutines serving
clients, Natis said. "However, not all business processes and
software
topologies fit this model."

With SOA 2.0, an event-driven architecture is deployed in which
software modules are related to business components, and alerts and
event notifications are featured. The initial SOA concept has not
been
event-driven but instead has featured direct calls from one piece of
software to another in a client-server process, Natis said. SOA
implementations have focused on Web services and subordinates to
clients, he said.

SOA 2.0 applications could include order processing systems, hospital
admissions processes or bank transactions, Natis said.

Oracle is positioning its Fusion middleware components as a solution
for SOA. Oracle sees the Java Platform, Enterprise Edition 5 (Java EE
5), SOA 2.0 and Web 2.0 coming together to produce a more productive
application platform, said Thomas Kurian, Oracle senior vice
president. Web 2.0 features more dynamic clients.

You can read this in full at:

Cruise Control Step by Step procedure

2006-05-24T06:41:00.000-07:00

Following steps might be useful while installing cruise control:

Please Note:
1. These steps were created in one of our projects and by a team member. Many of the folders are hard coded. The developer needs to modify the folder names appropriately.
2. There could be other ways to set up and more easily.

Installation of the Cruise Control
-----------------------------------
Version : Cruise Control 2.3

INSTALL PROCEDURE

NOTE: It is VERY, VERY important that you follow this procedure carefully and exactly with NO changes.
CruiseControl can be quite finicky and takes a long time to debug if it doesn't work right!

Pre-requisite: (on the machine where cruise control is running)
---------------------------------------------------

Tortoise CVS should be installed.
Tomcat 5.0 is installed
JSDK1.4.2 version or above
ANT 1.6 or above

Folder Structure
---------------------------------------------------
-Create a Folder continuousintegration on c:
c:\continuousintegration
-cruisecontrol
-builds
-artifacts
-checkout

Installation Steps:
-------------------

1) Create the Folder structure as shown in above.

2) Install the Tortise clint on the machine where the cruise control is running.
(required to update the files from repository)

3) Install the Java SDK 1.4.2_06 in "c:\j2sdk1.4.2_06" and set JAVA_HOME to the same.
or set the JAVA_HOME where you have the JSDK installed.

4) Install Tomcat 5.0 in "c:\Tomcat5.0" (no spaces!) and set CATALINA_HOME to "c:\Tomcat5.0". Use port 80 during the installation and note down the administrator username and password tht you supply(username:admin password: admin).

5) set ANT_HOME variable in the System's environment to "C:\continuousintegration\apache-ant-1.6.2"
or set the ANT_HOME where you have the ant folder.

6) download the cruisecontrol-2.3.0.1.zip version from the below link and extract this folder in the path
C:\continuousintegration\cruisecontrol downloadlink :http://cruisecontrol.sourceforge.net/download.html

- And set CCDIR variable in the System's environment to
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main"
(This is path of the cruise control which you extracted)

- copy the config.xml file attached with this document into path
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin"

7) Prepend "%JAVA_HOME%\bin;%ANT_HOME%\bin" to the PATH variable in the system environment

8) Restart the machine. This is necessary for the PATH changes to take effect for creating a Service

9) Start Tomcat. Go to "http://localhost/manager/html" and login in using the administrator login and password.

10) Before deploying the cruisecontrol.war on tomcat, build the cruisecontrol.war through command prompt.
follow steps
-go to command pomopt "C:\Downloads\cruisecontrol-2.3.0.1\reporting\jsp"
-execute command C:\Downloads\cruisecontrol-2.3.0.1\reporting\jsp>build war;
-build will start now and will ask for the fallowing inputs so plese input associated values
as given below.
-set.log.dir:
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin\log"
-set.status.file:
"currentbuildstatus.txt"
-set.artifaacts.dir:
"C:\continuousintegration\cruisecontrol\builds\artifacts"

-confirm that your build is successfull.

11) Using the "WAR file to deploy" section, deploy
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\dist\cruisecontrol.war" into
"C:\Tomcat5.0\wepapps" Tomcat. You should be able to see the cruisecontrol jsp application in a browser at "http://localhost/cruisecontrol". This does NOT mean that cruisecontrol process is running.

12) Check out your project, and copy/cut the entire "checked out source code" folder and paste it into "C:\continuousintegration\cruisecontrol\builds\checkout".

13) Go into the "C:\continuousintegration\cruisecontrol\builds\checkout\" folder and run "ant war" to verify that an ant build works in this directory.

14) Run "InstallCruiseControlService.bat" from directory "C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin" in a command shell.

15) If you go to "Start->Control Panel->Administrative Tools->Services", you should now be able to see a service called "CruiseControl".

16) Change the service to "Automatic" and start it. This should run the service. Check by typing "http://localhost:8000" into a browser. This should bring up the cruisecontrol's JMX control panel.

17) Click on the link named "CruiseControl Project:name=" To view the attributes set for the cruisecontrol.

18) Run "cruisecontrol.bat" from directory
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin" in a command shell.
If the console did't throw any exception then Hopefully your cruise control will be working fine
and it will continously look for the modification at your repository.

19) See your console for your cruise controle activities or you can see the log files from
C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin\logs

Some of the Usefull Reference Sites:
http://cruisecontrol.sourceforge.net/
http://cruisecontrol.sourceforge.net/main/configxml.html
http://www.javaranch.com/journal/200409/DrivingOnCruiseControl_Part1.html
http://www.javaranch.com/journal/200410/DrivingOnCruiseControl_Part2.html

Configuration files
---------------------
1. config.xml ==> Generally available in: C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin

2. CruiseBuild.xml ==> available in your source code folder. Should contain the CVSRoot info.

3. use "\" appropriately while mentioning folder structure based on your operating system.

4. Take special care while specifying the environment variables. I got stuck while appending "%ANT_HOME%"\bin to the PATH. Finally, I expanded ANT_HOME to proper windows directory and pasted onto PATH.

5. Ensure that the log file directory is properly set. Mostly it would be:
"C:\continuousintegration\cruisecontrol\cruisecontrol-2.3.0.1\main\bin\logs\
You can also set the log directory at the time of building the Cruisecontrol WAR OR you can change the log dir in web.xml after deplopying Cruisecontrol on tomcat

Amazon being a technology company

2006-05-18T04:07:00.000-07:00

All these days when somebody talked about Amazon, first thing I used to visualize was some software book image on the web browser !!! But following article changed the way I look at amazon, as a Technology company !!

http://www.acmqueue.com/modules.php?name=Content&pa=showpage&pid=388&page=3

I remember reading it somewhere that McDonald's is not really into making burgers but are into real estate. Now I can see what I read !!!

Difference between Transfer and Transport protocol

2006-05-17T05:02:00.000-07:00

Here is a good definition of transfer and transport protocol found on SOA discussion forum.

They're two different protocols of the stack that play
entirely different, non-overlapping roles. Transport is for
moving bits around the network. Transfer is for exchanging
data between applications. Transfer uses transport.

In OSI-speak (since somebody brought it up) IIOP, SOAP (as
commonly used), etc.. are layer 5/6 protocols, while transfer
protocols are layer 7. That's why I've always got a chuckle
about those try to put SOAP over HTTP 8-)

Big Upfront Framework design (BUFD)

2006-04-03T20:13:00.000-07:00

Recently I have been thinking is it really worth doing Big Upfront Framework Design(BUFD).
I have taken part in designing several frameworks in my past, but never thought(or didnt get a chance) the best phase to design frameworks. It is agreed by default that frameworks are designed upfront before product development begins. Many highly intelligent architects, designers sit together for days and nights without proper sleep and design meta data driven,XML based,database independent frameworks!!!. But if we carefully look into this, upfront framework design is not really agile, and secondly, ROI is also bad.

* Doing Upfront Framework Design(UFD), would force the designers and developers to design application or develop application to fit the framework, rather than steering the development effort in satisfying the customer's requirements.

* UFD, is not profitable to the customer, because frameworks are generally designed to be as generic as possible keeping future requirements in mind, and due to which, customer would be spending money on "future" requirements in the present!!!

In fact I was trying to think can UFD be applied to Project development scenario, where the project's duration is less than a year ???... Now I feel that it does not suit here too. The reason being, any framework design and development would take atleast 3-4 months, and I feel this effort is not worth spending for a shorter duration project !!

Ok, the best possible solution could be:

* Start thinking about framework from the beginning (dont stop yourself), but dont start the design until you pass the inception pase.

* Start laying the foundation from Elaboration phase.

* As the product development progress, design, tweak the framework iteratively.

* The Framework should evolve over a period of time, and at the same time ensure that is "usable" (need not be complete) before construction phase !!

* keep refactoring, evolving and be agile

Cleared SCEA Part 1 Exam

2006-04-02T20:37:00.000-07:00

March 31st 2006: I cleared the Sun Certified Enterprise Architect exam. I was planning to take up this exam from some time, and in the last 3 days I really put some effort and passed the exam with good scores.

I have scored 100% in many of the following objectives, especially the ones that I am passionate about like Design patterns, EJB, Applicability of J2EE, Legacy Connectivity(even though I dont like this subject I know a bit), protocols, messaging.

Exam Objectives

Section 1: Concepts
* Draw UML Diagrams
* Interpret UML diagrams.
* State the effect of encapsulation, inheritance, and use of interfaces on architectural characteristics.

Section 2: Common Architectures
* Recognize the effect on each of the following characteristics of two tier, three tier and multi-tier architectures: scalability maintainability, reliability, availability, extensibility, performance, manageability, and security.
* Recognize the effect of each of the following characteristics on J2EE technology: scalability maintainability, reliability, availability, extensibility, performance, manageability, and security.
* Given an architecture described in terms of network layout, list benefits and potential weaknesses associated with it.

Section 3: Legacy Connectivity
* Distinguish appropriate from inappropriate techniques for providing access to a legacy system from Java code given an outline description of that legacy system

Section 4: Enterprise JavaBeans Technology
* List the required classes/interfaces that must be provided for an EJB technology.
* Distinguish stateful and stateless Session beans.
* Distinguish Session and Entity beans.
* Recognize appropriate uses for Entity, Stateful Session, and Stateless Session beans.
* State benefits and costs of Container Managed Persistence.
* State the transactional behavior in a given scenario for an enterprise bean method with a specified transactional deployment descriptor.
* Given a requirement specification detailing security and flexibility needs, identify architectures that would fulfill those requirements.
* Identify costs and benefits of using an intermediate data-access object between an entity bean and the data resource.

Section 5: Enterprise JavaBeans Container Model
* State the benefits of bean pooling in an EJB container.
* State the benefits of Passivation in an EJB container.
* State the benefit of monitoring of resources in an EJB container.
* Explain how the EJB container does lifecycle management and has the capability to increase scalability.

Section 6: Protocols
* Given a scenario description, distinguish appropriate from inappropriate protocols to implement that scenario.
* Identify a protocol, given a list of some of its features, where the protocol is one of the following: HTTP, HTTPS, IIOP, JRMP.
* Select from a list, common firewall features that might interfere with the normal operation of a given protocol.

Section 7: Applicability of J2EE Technology
* Select from a list those application aspects that are suited to implementation using J2EE.
* Select from a list those application aspects that are suited to implementation using EJB.
* Identify suitable J2EE technologies for the implementation of specified application aspects.

Section 8: Design Patterns
* From a list, select the most appropriate design pattern for a given scenario. Patterns will be limited to those documented in Gamma et al. and named using the names given in that book.
* State the benefits of using design patterns.
* State the name of a design pattern (for example, Gamma) given the UML diagram and/or a brief description of the pattern's functionality.
* Select from a list benefits of a specified design pattern (for example, Gamma).
* Identify the design pattern associated with a specified J2EE feature

Section 9: Messaging
* Identify scenarios that are appropriate to implementation using messaging, EJB, or both.
* List benefits of synchronous and asynchronous messaging.
* Select scenarios from a list that are appropriate to implementation using synchronous and asynchronous messaging.

Section 10: Internationalization
* State three aspects of any application that might need to be varied or customized in different deployment locales.
* Match the following features of the Java 2 platform with descriptions of their functionality, purpose or typical uses: Properties, Locale, ResourceBundle, Unicode, java.text package, InputStreamReader and OutputStreamWriter.

Section 11: Security
* Select from a list security restrictions that Java 2 environments normally impose on applets running in a browser.
* Given an architectural system specification, identify appropriate locations for implementation of specified security features, and select suitable technologies for implementation of those features.

Who is an Architect ?

2006-03-22T08:31:00.000-08:00

I found this interesting definition as per James Mcgovern:

think of a good architect as someone who really understands the systems they oversee - not just the classes and the collaborations but the real 'soul' of the system. They're the sort of person who, given a particular change in requirements for their system, will come up with three different solutions but will instinctively know which is the right one to go for (and will then find all the technical justification in terms of changability, performance, robustness, etc.) because they know the system so well. They probably love the system a bit too.

Interesting definition of Enterprise Architecture

2006-02-25T10:10:00.000-08:00

I found this interesting definition of EA:

Enterprise Architecture is an infrastructure and a set of Machines constructed in order to manage a chaotic, dynamic, unpredictable, complex, organic, prone to error, frustrating, Enterprise IT, which has to support an ever increasing, dynamic portfolio of products and services, through constant "ASAP, Now, Right-Away" modifications of business processes.

What you choose

2006-02-21T21:29:00.000-08:00

You can make it happen when you truly choose to do so. You always have, and you always will.
If something is important enough to you, you'll surely find a way. Look back on your life up to this point, and you'll see a manifestation of what you've cared most about.
Now take a look at what you care most about in this very moment. Those are the things you will give your energy and attention to, and those are the things that will surely happen for you.
You are plenty capable of pushing yourself relentlessly toward what you choose. For you do it every day and you've had a lifetime of practice.
The big question is this. What exactly do you choose?
Whatever it is, whatever you truly care about in your hjavascript:void(0);
Publish Post eart of hearts, you'll find a way to make it real. With that in mind, always choose the very best you can imagine.
-- Ralph Marston

Out of your vulnerabilities will come your strength.
-Sigmund Freud

Spring to implement Failover mechansim

2006-02-17T07:08:00.000-08:00

<bean id="highAvailabilityBean" class="org.springframework.remoting.support.FailoverProxyFactoryBean">
<property name="serviceInterface" value="com.x.MyInterface"> <property name="serviceBeans"> <list>  <ref bean="primaryServiceProvider"> <ref bean="fallBackServiceProvider"> </ref> </ref></list>
package org.springframework.remoting.support;import java.lang.reflect.InvocationTargetException;import java.util.Iterator;import java.util.List;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;import org.springframework.aop.framework.ProxyFactory;import org.springframework.beans.factory.FactoryBean;import org.springframework.beans.factory.InitializingBean;import org.springframework.remoting.support.RemoteAccessor;/*** Factory bean for proxies to redundant services. Behaves like theproxied* service when used as bean reference, exposing the specified service* interface, but with transparent fail-over. All call to the proxy are* delegated to the first object in the list of service providers (@see* #setServiceProviders(List)). When this delegated call fails, thenext* provider in the list will be called, etc.** @author be324288**/public class FailoverProxyFactoryBean extends RemoteAccessor implementsMethodInterceptor,InitializingBean, FactoryBean {private Object serviceProxy;private List serviceProviders;/*** The list of (redundant) objects that implement the interfacespecified* with {@link RemoteAccessor#setServiceInterface(java.lang.Class)}** @return*/public List getServiceProviders() {return serviceProviders;}/*** @param serviceProviders*/public void setServiceProviders(List serviceProviders) {this.serviceProviders = serviceProviders;}public void afterPropertiesSet() throws Exception {if (getServiceInterface() == null) {throw new IllegalArgumentException("serviceInterface isrequired");}if (serviceProviders == null || serviceProviders.isEmpty()) {throw new IllegalArgumentException("serviceBeans isrequired");}for (Object o : serviceProviders) {if (!getServiceInterface().isInstance(o)) {throw new IllegalArgumentException(o.getClass()+ " does not implement the serviceInterface: "+getServiceInterface());}}this.serviceProxy =ProxyFactory.getProxy(getServiceInterface(), this);}public Object getObject() {return this.serviceProxy;}public Class getObjectType() {return getServiceInterface();}public boolean isSingleton() {return true;}public Object invoke(MethodInvocation mi) throws Throwable {Iterator iter = serviceProviders.iterator();while (iter.hasNext()) {Object bean = iter.next();try {returnbean.getClass().getMethod(mi.getMethod().getName(),(Class[])mi.getMethod().getParameterTypes()).invoke(bean,mi.getArguments());} catch (InvocationTargetException e) {// try next bean or throw exception if this is the lastbeanif (!iter.hasNext()) {throw e.getCause();}}}return null;}}

Failover mechansim using Spring

2006-02-17T06:59:00.000-08:00

Here is a sample code snippet about how spring can be used to handle fail over mechansim: (Ref: from a Spring framework discussion forum)

class="org.springframework.remoting.support.FailoverProxyFactoryBean">

package org.springframework.remoting.support;

import java.lang.reflect.InvocationTargetException;
import java.util.Iterator;
import java.util.List;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.remoting.support.RemoteAccessor;

/**
* Factory bean for proxies to redundant services. Behaves like the
proxied
* service when used as bean reference, exposing the specified service
* interface, but with transparent fail-over. All call to the proxy are
* delegated to the first object in the list of service providers (@see
* #setServiceProviders(List)). When this delegated call fails, the
next
* provider in the list will be called, etc.
*
* @author be324288
*
*/
public class FailoverProxyFactoryBean extends RemoteAccessor implements
MethodInterceptor,
InitializingBean, FactoryBean {

private Object serviceProxy;

private List serviceProviders;

/**
* The list of (redundant) objects that implement the interface
specified
* with {@link RemoteAccessor#setServiceInterface(java.lang.Class)}
*
* @return
*/
public List getServiceProviders() {
return serviceProviders;
}

/**
* @param serviceProviders
*/
public void setServiceProviders(List serviceProviders) {
this.serviceProviders = serviceProviders;
}

public void afterPropertiesSet() throws Exception {
if (getServiceInterface() == null) {
throw new IllegalArgumentException("serviceInterface is
required");
}
if (serviceProviders == null || serviceProviders.isEmpty()) {
throw new IllegalArgumentException("serviceBeans is
required");
}
for (Object o : serviceProviders) {
if (!getServiceInterface().isInstance(o)) {
throw new IllegalArgumentException(o.getClass()
+ " does not implement the serviceInterface: "
+
getServiceInterface());
}
}
this.serviceProxy =
ProxyFactory.getProxy(getServiceInterface(), this);
}

public Object getObject() {
return this.serviceProxy;
}

public Class getObjectType() {
return getServiceInterface();
}

public boolean isSingleton() {
return true;
}

public Object invoke(MethodInvocation mi) throws Throwable {
Iterator iter = serviceProviders.iterator();
while (iter.hasNext()) {
Object bean = iter.next();
try {
return
bean.getClass().getMethod(mi.getMethod().getName(),
(Class[])
mi.getMethod().getParameterTypes()).invoke(bean,
mi.getArguments());
} catch (InvocationTargetException e) {
// try next bean or throw exception if this is the last
bean
if (!iter.hasNext()) {
throw e.getCause();
}
}
}
return null;
}

}

Tao of Software Architect

2006-01-18T15:45:00.000-08:00

The Tao of the Software Architect

I read about this article from one of the architect’s discussion forum

Lao-Tsu, revisited by
Philippe Kruchten
This is a very liberal reading of Lao-Tsu’s Tao Te Ching for the use of software architects, based on various French and English translations. The number refers to the original tablets.
The architect observes the worldbut trusts his inner vision.He allows things to come and go.His heart is open as the sky. (12)
The architect doesn't talk, he acts.When this is done,the team says, "Amazing:we did it, all by ourselves!" (17)
When the architect leads, the teamis hardly aware that he exists.Next best is a leader that is loved.Next, one who is feared.The worst one who is despised. (17)
A good traveler has no fixed plansand is not intent upon arriving.A good artist lets his intuitionlead him wherever it wants.A good scientist has freed himself of conceptsand keeps his mind open to what is. Thus the architect is available to everybodyand doesn't reject anyone.He is ready to use all situations and does not waste anything.This is called embodying the light. (27)
If you want to shrink something,you must first allow it to expand.If you want to get rid of something,you must first allow it to flourish.If you want to take something,you must first allow it to be given.This is called the subtle perceptionof the way things are.The soft overcomes the hard.The slow overcomes the fast.Let your workings remain a mystery.Just show people the results. (36)
When the process is lost, there is good practice.When good practice is lost, there are rules.When rules are lost, there is ritual.Ritual is the beginning of chaos.*(38)
The architect concerns himselfwith the depth and not the surface,with the fruit and not the flower. (38)
The architect allows things to happen.He shapes events as they come.He steps out of the waysand let the design speak for itself. (45)
The architect gives himself upto whatever the moment brings.He knows that he is going to leave,and he has nothing left to hold on to:no illusions, no resistance in his mind.He holds nothing back from the project,therefore is ready for departure†,as a man is ready for sleepafter a good day's work. (50)
The great way is easy,yet programmers prefer the side paths.Be aware when things are out of balance.Remain centered within the design. (53)The architect's power is like this.He let all things come and goeffortlessly, without desire.He never expect results;thus he is never disappointed.He is never disappointed,thus his spirit never grows old. (55)
Those who know don't talk.Those who talk don't know. (56)
Alternate:
Those who do not have a clue are still debating about the process.Those who know, just do it. (56)
The architect is contentto serve as an exampleand not to impose his will.He is pointed, but doesn't pierce.Straightforward, but supple.Radiant, but easy on the eyes. (58)
If you want to be a great leader,stop trying to control.Let go of fixed plans and concepts andthe team will govern itself.The more prohibitions you have,the less disciplined the team will be.The more coercion you exert,the less secure the team will be.The more external help you call,the less self-reliant the team will be. (57)
————* Sounds a bit like the SEI CMM! Jim Archer said: "First you pay for results, Then you pay for effort, Finally you pay for attendance."† Especially when he’s only a Rational consultant.