Next Stop: JXTA - An Open Platform for P2P

While I was researching on different P2P technologies, JXTA came to my attention. "JXTA (Juxtapose) is an open source peer-to-peer protocol specification begun by Sun Microsystems in 2001. Sun remains actively involved in the development and promotion of JXTA. The JXTA protocols are defined as a set of XML messages which allow any device connected to a network to exchange messages and collaborate independently of the underlying network topology. JXTA is the most mature[citation needed] general purpose P2P framework currently available and was designed to allow a wide range of devices - PCs, mainframes, cell phones, PDAs - to communicate in a decentralized manner." (Quoted from Wikipedia http://en.wikipedia.org/wiki/JXTA)

JXTA is indeed language-independent. There are C/C++, J2SE and J2ME implementation available for now. JXTA is also platform-independent. It can be implemented on different OS platforms. Simply speaking, it is an open technology just like TCP/IP. It sounds perfect, doesn't it? I think it fits into my project because:

• It is an open and generic purpose P2P technology - It defines a set of protocols that developers can use to build almost any P2P application. At the same time, these protocols are flexible enough to be easily adapted to application-specific requirements.
  
• It is platform-independent - This is one of my project's goal.
  
• It is open sourced - Sweet and smile.
  

However, some concerns and uncertainties still exist.

• Is JXTA going to be improved over a long time?
  
• Is JXTA going to be surviving given that Sun will be purchased by Oracle?
  

I've checked JXTA's developers list and list of projects which are using JXTA. I didn't find one significant enough to attract public attention. Is it still too early to adopt an new technology as JXTA? I don't know. I'm not worry about Java, but I'm worry about those guys who are contributing to JXTA project. Without the major supporter Sun, is JXTA able to grow?

Any ways, I know what I'm going to do now. I was inspired by P2P technology. I have decided that my system should be easily integrated with P2P, or should not be tied to a single architecture, e.g. client/server technology, at least when it comes to design phase. A new design class diagram is done. An abstract network/message layer, which will be implemented according to actual underline network, was added. Hopefully this design is flexible enough to be implemented in the future.

P2P or C/S? It Is Not Just A Technical Consideration

I have been always thinking the architecture of new system should ideally not be pure Client/Server because of the concern that

1. server's operating cost potentially will be very high, and
2. it will be very hard to maintain servers with high volume of transactions

I have experienced the difficulties of accessing TOM servers when there were major events hosted on their servers. From what I observed, the maximum number of concurrent users in each server is about 2500 - 3000. I can not even connect to any of their four servers some times because they are all full load. I don't have similar experience with KGS or IGS, but from what KGS shows on their server's statistics page, I can tell the maximum number of concurrent users never exceeds 3000, besides the data traffic is huge (total data for the day of May-06-2009 is about 128GB). See the screen shot at the bottom for reference. I don't think it is easy to run such a system in the early stage before I can get financial support from outside source.

My colleague James introduced me to book P2P - Networking and Applications, 2009 by Elsevier Inc, ISBN: 978-0-12-374214-8. I have to say it is an excellent book. It not only answered me so many questions (theoretical and practical), but also directed me to a much brighter future. I feel it is even more fun to work on this project.

Sure my application is quite different from most popular P2P applications, which are mainly for file sharing or multimedia streaming. But from content delivery point of view, it does the very same thing that is delivering contents to as many receivers as possible by means of high efficiency and low cost. So it is interesting to find out:

1. Is P2P applicable to my system?
2. If it is, what complexity will be added to my system?
3. What will be the impacts of using P2P model in my system from business perspective?
4. Should I build it from scratch or based on third party platform if there is such a platform?

All above questions have to be clearly answered before I move on to next phase of project, which is Architecture Design.

Meet GRASP. It Is Still Not Too Late

I kept reading on Craig's Apply UML and Patterns and came to Chapter 17 - GRASP: Designing Objects with Responsibilities. This is a very important chapter. I'm lucky that I was caught by it in the right time, just before I was otherwise going too far. I thought I should start working on System Architecture design. I now know I have to carefully assign responsibilities to objects in the first place before I move on. It's worth to pause the development progress for a little while, hopefully for a better result.

It's Fun Part

OK. It comes to fun part now. I've finished Sequence Diagram and Design Class Diagram using UMLet. I have to use UMLet instead of Modeler because there is not a Sequence Diagram tool in my current version of Modeler, and I don't want to spent too much time on seeking and configuring newer version. UMLet works just fine as a UML drawing tool. So be it.

To be honest, I had to change my design many times while I was drawing SD and DCD because what I'm developing is not just a IGS client. There are many things that could be done in my project. I have to well plan for them. This project is actually a totally new system, not only from functional perspective but from technology point of view as well.

It's time to consider the system architecture now.

Finish First Domain Model

After coming back from vacation, I finished the first domain model using class diagrams today. I basically followed the guidelines that combine both book of Applying UML and Patterns and UML 2.0 in a Nutshell.

By the way, I went to Seattle and Portland with family for fourdays. It was a wonderful trip.

Complete Reading "Writting Effective Use Cases"

Done. I finally complete reading the book Writing Effective Use Cases (draft). This is a excellent book indeed. I started writing and modifying my use cases following the guideline described by Alistair Cockburn, the author of this book. I feel like a student following the teacher's instructions to achieve the learning goal step by step. How wonderful the learning experiences are!

Now, it is time to move into design.

Is Palm Going To Win Programmers Back with WebOS

Palm announced an early access program for developers to test-drive and provide feedback on the their Mojo SDK prior to its public release last week. According to what Mitch Allen described in his new book Palm webOS (O'Reilly, 2009), it seems like WebOS is a very interesting mobile platform. It provides multi-task (background application) capability that iPhone lacks, flexible notification system (Popup and Banner vs. iPhone's Popup only), and rich services (native on-device services and cloud services). I think supporting cloud services makes a lot sense. Because it not only widens the application rang that a mobile device can be used for, but also makes the mobile development far more easier. However, how all of these promises are going to work in reality? Is Palm able to deliver what they have promised? Is Palm going to win programmers back? Let's see.