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Ever heard of Factory Methods?

Wed, 04 Feb 2009 02:26:00 +0100

Whenever we want an object to initialize itself, we normally go for public constructor definition. But have you ever think about static factory method? A class can provide similar or some addition fetchers as in constructor to its clients with static factory method.

Factory methods are simply methods that instantiate objects. Some factory methods in the Java 2 API that you would likely have used are the getInstance() and valueOf() methods. getInstance() is the conventional instantiation method in singletons, while valueOf() are often type-conversion methods, like in String.valueOf(int i).

Constructor allows object to initialize themselves when they are created. Once defined, the constructor is automatically called immediately as the object is created, before the new operator completes.

A simple example of constructor:

ConstructorExample.java
class ConstructorDemo
{
    public int a=42;
    ConstructorDemo()
    {
        System.out.println(”a = ” + a);
    }
}

class ConstructorExample
{
    public static void main(String [] args)
    {
        ConstructorDemo ConObj = new ConstructorDemo();
    }
}

Output:
a = 42

There is a less popular technique that should also be a part of every programmer’s toolkit for the similar propose of constructor. A class can provide a public static factory method, which is simply a static method that returns an instance of the class. When a method is static, it can be accessed before any objects of its class are created, and without reference to any object.
Static factory methods have names

Static factory methods have names
A class can have only a single constructor with a given signature, which is a restriction in cases where a class needs to be able to be instantiated using identical parameter lists. In cases like this, you can replace constructors with static factory methods with more intuitive names that highlight their differences.

Static factory methods can improve performance
This is because static factory methods do not have to actually instantiate new objects each time they are invoked. This is what allows for the Singleton pattern, where a single instance is returned. It also allows instances to be cached within the object in cases where object instantiation is expensive (like for the case of instantiation of fields from a database) or frequently done.

Static factory methods can return a subtype of their return type
This allows for interfaces to be returned by static factory methods, which is best exemplified in the Collections Framework. Needless to say, forcing a client to refer to the returned object by its interface rather than its actual class is a good practice.

Also, the class of the object returned can be private (non-public), so there is a degree of encapsulation where the private class can be modified without impacting clients of the API (possibly for bug-fixing or improvements, or just plain maintainence). The private classes can also vary depending on the parameters to the static factory, so long as they are subtypes of the return type, allowing for greater flexibility.

Classes without public or protected constructors cannot be subclassed
This is an unavoidable fact, so classes designed for inheritance must have at least 1 public constructor to be able to be subclassed.

A simple example of a static factory method:

StaticExample.java
class StaticDemo
{
    static int a=42;
    static void callme()
    {
        System.out.println(”a = ” + a);
    }
}
class StaticExample
{
    public static void main(String [] args)
    {
        StaticDemo.callme();
    }
}

Output:
a = 42

Providing a static factory method instead of a public constructor has both advantages and disadvantages.

The advantages of static factory method are:

Unlike constructor, it has names which make class easier to use.
Unlike constructor, they are not required to create a new object each time they are invoked.
Unlike constructor, they can return an object of any subtype of their return type.

The disadvantages of static factory methods are:

Classes without public or protected methods cannot be subclassed.
They are not readily distinguishable from other static method.

In conclusion, you can use static factory methods for a more intuitive API, to improve performance via object-caching, to implement singletons, in interface-based frameworks, and to return objects of private classes; and use constructors in classes designed for inheritance (there shouldn’t be many of these) and for greater visibility in API documentation (since they appear in a separate table in standard Javadocs).

LAU Byblos Computer Science School in action

Thu, 22 Jan 2009 14:24:42 +0100

Wednesday, January 21st, 2009, 2:00 pm. That was the date when the computer science department, faculty and students, met for discussions.

It was kinda cool gathering in a friendly atmosphere that allowed the students to chit-chat with their teachers. The new generation of LAU’s computer scientists was introduced to the seniors as well as to the faculty of the school.

The first thread was about the concerns and unsatisfactions of the new and continuing students according to their learning experience at the Computer Science Program. The new students had wonderful ideas to claim as well as the more experienced students who called for learning a second programming language in the program.

Later on, the gathering became multithreaded in a very funny way where every two or three students started a conversation with one of the faculty members. Nevertheless, it was very profiting for the new students who some of them is getting ready to an interview about his knowledge in Java, for he might start working on a university project with a faculty member and get his first professional income. The seniors as well, they preferred to pick threads about their graduate programs and universities and asked the faculty for some advising.

Some handouts were distributed to the attendees, mentioning the educational objectives and learning outcome of both the program and the student.

The program must prepare computer science graduates for computer science related careers, locally and abroad, with a broad knowledge of the computing field, related principles, tools, and theories. That means LAU computer science graduates must fit easily in local and international computing field related careers.

The program must develop graduates who are committed for a life-long learning, capable to work effectively in teams, and who possess good communication skills. That means the graduate student must always be prepared for updates in his field.

The program must introduce, outreach and engage by allowing computer science faculty and students to contribute to the community at large. Like organizing training camps for high school students let’s say, or even helping the community on an individual basis like introducing the program to highschoolers of the neighborhood.

The program must make the graduates aware of cultural, social, legal, and ethical issues inherent in the discipline of computing. The best example is the “Social and Professional Issues in Computing” course which is also known among students as “Computer Ethics”.

The students shall be able to apply their computational and mathematical knowledge in order to solve computational problems of varying complexity.

Students shall develop the ability to analyze a problem, identify, define, and verify the computing requirements appropriate to its solution.

Students shall have the ability to design, evaluate, and implement an efficient and correct algorithm, computer-based system, process, component, or program that meet desired needs.

Students shall learn to work effectively and interactively in teams in order to accomplish a common goal.
Students shall develop an understanding of the ethical and social issues related to computing.

Students shall have the ability to effectively present, transmit, and communicate their work, written as well as orally, to colleagues and to clients.

Students shall develop the ability to analyze the local and global impact of the computing field on individuals, organizations, and society.

Students shall have an understanding of current technology trends as well as future directions and shall recognize the need and develop the necessary skills for continued and professional development.

Student shall develop the ability to use current techniques, skills, and tools necessary for computing practices.

Students shall develop the ability to apply mathematical foundations, algorithmic principles, and computer science theory in the modeling and design of computer-based systems in a way that demonstrates comprehension of the tradeoffs involved in design choices.

Students shall develop an understanding of the life cycle for software system development including requirements elicitation, specification, prototyping, design, GUIs, implementation, testing and documentation.

And finally, students shall develop an understanding of complexity analysis and various algorithmic paradigms.

Power User's Guide to Firefox 3

Fri, 19 Dec 2008 13:12:57 +0100

You already know about Firefox 3's marquee new features, but now it's time to dig deep and unearth the shortcuts, tweaks, and even Easter eggs that Mozilla marketing doesn't mention. In honor of today's official release of Firefox 3—at 10AM Pacific Time—let's dive in past Firefox 3's most talked-about feature-set into its lesser-known power uses, tricks, and customizations.

Shrink the Super-sized Back Button

The very first thing you notice in Firefox 3 is its extra large Back button. While it's actually quite handy—less chance of missing your target!—if the Back button's just too big for your tastes, it's as easy as pie to reduce. Just right-click on Firefox's toolbar, and choose Customize. In the dialog box, select "Use small icons."

Adjust the Smart Location Bar's Number of Suggestions

adjustsuggestion.pngThe Firefox 3 feature that you'll get to know and love the most is the new smart location bar's as-you-type suggestions that learn where you probably want to go as you browse. But if you're feeling like the number of suggestions is too high or too low? Adjust it to your liking in Firefox's configuration area. Here's how.

Enter about:config into the address bar and hit Enter.
Press the "I'll be carefull. I promise!" button. (Because you will be.)
Enter browser.urlbar.maxRichResults in the Filter field to reach this preference.
Set it to your desired number of suggestions. Three shown here.

Delete Mistyped URL Suggestions and Other Auto-complete Entries

shiftdelete.pngWhile the Smart Location bar is quite intelligent, if you enter an incorrect URL—say, to a page that doesn't exist, or a parked domain—Firefox 3 will still remember it and suggest it again later. (Garbage in, garbage out, as they say.) To remove a mistyped URL from your suggestion list forever, key down to the suggestion and type Shift+Delete on the Mac, and just Delete on Windows. This trick also works for any form auto-complete entry, like if you mistype a username into a login form.

Ditch Obselete Extensions

Firefox's philosophy seems to be "stay lean and mean and leave the extras to add-ons." Nevertheless, Firefox 3 does bake in some functionality that makes some extensions you might love unnecessary. Here are five extensions you won't need with Firefox 3.

Revert the "AwesomeBar" with Oldbar

oldbar.png Firefox's smart location bar (a.k.a. "AwesomeBar")—which drops down a suggestion list of destinations as you type into it—is extra verbose and extra-tall, since it includes both web site titles and URLs. If you're missing Firefox 2's classic one-line drop-down look, the Oldbar extension can revert the "AwesomeBar" to something less awesome—or at least something that looks less awesome.

Trick Out Your Smart Bookmarks

smartbookmarks1.png Like iTunes Smart Playlists and saved search folders in OS X and Vista, Firefox 3's Smart Bookmarks are dynamic lists of URLs generated by certain search criteria. Here's how to create your own collections of Smart Bookmarks using search parameters. Hint: Add the most frequent pages you visit on Lifehacker.com by bookmarking place:queryType=0&sort=8&maxResults=5&domain=lifehacker.com.

Set Gmail as Your Default Email client—Without an Add-on

gmailfx3.png Firefox 3's filetype handling mechanism can now associate web applications as well as desktop applications with certain files. This opens the door to possibilities like automatically launching links to ical files in your web-based calendar app, or opening your webmail when you click on email links. While most webapps have to catch up to Firefox 3 to enable this functionality, one we already know and love is already there. Here's how to launch Gmail when you click mailto: links on web pages.

Say Hello to the Firefox Robots

You already know about the age-old Firefox about:mozilla Easter egg. Well, Firefox 3 has a new Easter egg that pays homage to its robot mascot. Type about:robots into the Firefox 3 address bar to get a fun page with a list of robot pop culture references, from I, Robot to Blade Runner to Battlestar Galactica to Futurama.

Enable Spellchecking in One-line Input Fields

typo.png This tweak goes back to Firefox 2, but is still just as useful and functional in Firefox 3, especially if you're a web writer. In about:config, set layout.spellcheckDefault value equal to 2 to enable spell-checking in single line input fields as well as textareas. (Less typos in your email subject lines and blog post titles!) Here are a few more Firefox about:config tweaks.

Mac Users: Add Favicons to Your Bookmark Toolbar

Mac users who are rockin' Firefox 3's new slick Mac-like theme—but who miss their bookmarks' favicons—can easily add web site icons to their toolbar with a little tweak.

What are 3G networks??!

Thu, 18 Dec 2008 23:20:52 +0100

What exactly are 3G networks, and why should we care? Here’s the story.. ;)

Phoning It In

3G is shorthand for the third generation of wireless network technology. 3G networks allow you to do all the science fiction things that weren’t possible to do before. :d

With 3G, mobile phones, handheld devices, and notebooks with 3G-compatible modems can easily handle high-speed multimedia content and serve as all-in-one communication, entertainment, and information devices, the promise goes. You’ll be able to hold a video-conference with your coworkers while simultaneously surfing the Web on your mobile phone. E-mail messages with file attachments will instantly download to your PDA or notebook. You can also pull up to an automated car wash, activate the sudsing with your 3G phone, and have the charge added to your phone bill, according to 3GNewsroom.com.

From 1G to 3G

The first generation of wireless networks, known as 1G, was a basic analog voice phone service without data capability.

With second-generation networks, or 2G, wireless technology progressed from analog to digital. These networks are still the most prevalent standard in use today. There are three main 2G network standards: CDMA (Code Division Multiple Access), GSM (Global System for Mobile Communications), and TDMA (Time Division Multiple Access). Each type has its own characteristics and features. For instance, GSM networks are global.

But 2G networks were primarily intended for digital voice services. Under ideal circumstances, 2G networks are painfully slow at sending data, reaching 10 to 19 kilobits per second, which is much less than half the speed of a traditional 56-kbps dial-up modem. And unless they’ve been especially optimized, most Web pages accessed from a 2G network inch across a handheld screen, which makes surfing the Web on a 2G wireless device as efficient as running underwater.

A few network providers introduced an interim standard, 2.5G technology that can handle speeds between 56 and 144 kbps. But for several years, the big push has been toward 3G, which promises data transfer rates of 144 kbps to 2 megabits per second, and an always-on connection.

Beyond the Propaganda

In addition, 3G networks aren’t nearly as prevalent geographically as 2G networks, so coverage can be spotty. And service plans are often expensive and confusingly structured. Users of the Sprint PCS Vision network, for instance, are billed according to the amount of data downloaded, which can be difficult to estimate and control.

Despite 3G’s current limitations, our testers concluded that the new networks are worth the price premium for mobile business users who need frequent access to e-mail and the Internet. But don’t expect to use your cell phone to have your car washed just yet. :P

Can you Flock? it's easy!!

Thu, 18 Dec 2008 23:44:13 +0100

Well, after almost a year and a half of using Mozilla Firefox, upgrading from version to version, Flock was finally released. The most powerful browser used for fun browsing and it can be the best for professional browsing.
Flock is a web browser built on Mozilla’s Firefox codebase that specializes in providing social networking and Web 2.0 facilities built into its user interface. Flock v2 was released on October 14, 2008.

About Flock

Internet users spend a lot of time going from one site to the next, keeping up with a variety of friends and interests. Flock pulls all of your favorite people, places and content together in a convenient view and delivers a more personal experience of the web, where its users are more easily connected to what's important to them.

Flock 2.0 integrates social networking and media services including MySpace, Facebook, YouTube, Twitter, Flickr, Blogger, Gmail, Yahoo Mail, etc. Notably, when logging into any of the supported social services, Flock can track updates from friends: profiles, uploaded photos, and more.

Other features include:

native sharing of text, links, photos and videos;
a "Media Bar" showing preview of online videos and photos as well as subscription to photo and video feeds;
a feed reader supporting Atom, RSS and Media RSS feeds;
a blog editor and reader, allowing direct posting into any designated blog;
a web-mail component allowing users to check supported web-based email off site, compose new messages, and drag-and-drop pictures and videos from the "Media Bar" or web clipboard into a new email message;
support for third-party add-ons, including a number of Firefox extensions

Download Flock 2.0.2 here:

enjoy it Flockstar ;)

Copy & Paste Arrives via Clever Javascript Hack (iPhone)

Thu, 18 Dec 2008 23:32:49 +0100

Yesterday, an online service called Pastebud was announced. So far, it offers what seems to be the best solution to what has been one of the iPhone’s greatest weaknesses, the cutting and pasting of text. However, there is only one caveat, the service only seems to currently work in the iPhone’s Mail app and Safari. Using some clever javascript programming, the developer, Jed Schmidt is able to copy selected text to his servers and then paste it back into the applications.

Mac OS X 10.5.6 fixes sync, graphics issues, more ...

Tue, 16 Dec 2008 13:51:20 +0100

As anticipated last week, Apple has posted its latest update to Mac OS X, v10.5.6. Available through the Software Update service or direct download, the patch consists mostly of dozens of fixes and performance enhancements, for issues such as sync and graphics. Sync reliability has been improved for Address Book, portable home directories and most notably MobileMe, which should now propagate contact, calendar and bookmark changes within a minute of their being saved. Graphics changes include "general improvements" for iChat, Aperture, Cover Flow and iTunes, and unspecified performance enhancements directed at gaming. More critically the update attempts to address problems with graphics distortion, triggered by some AMD/ATI video cards.

The size of the update may vary depending on processor platform and the currently installed OS; upgrading from an Intel Mac with v10.5.5 nets a 377MB download.

Other issues addressed by the update include problems with AirPort, iChat, Mail, networking and Time Machine. AirPort connections should now be more reliable when roaming in large Wi-Fi networks, for example, and iChat should no longer log a user out when changing status to invisible via AppleScript. Time Machine should be able to properly locate backup volumes, and among several Mail adjustments is a solution to junk messages being left in the inbox.

Networking changes incorporate stability and performance enhancements for TCP and AT&T 3G connections, as well as Apple File Service, namely when using a home directory located on an AFP server. The ssh Terminal command, lastly, should now be compatible with more ssh servers.

What is Windows 7?

Thu, 18 Dec 2008 23:45:59 +0100

It's the next version of Windows for PCs, and it's the result of working hand-in-hand with our partners and with people who use Windows in the real world every day. We're paying particular attention to the things they're telling us are important to them and will make their PCs work the way they want them to—things like enhanced reliability, responsiveness, and faster boot and shut-down. We're also trying to make their everyday tasks easier, like connecting and syncing devices, browsing the web, and managing a home network.

Of course, we're also working on new capabilities, so people will be able to do things with Windows 7 that were difficult (or perhaps impossible) to do with PCs before. Finally, we're working hard to ensure that Windows 7 will run on any PC and work with any program that works today with Windows Vista, so upgrading from Windows Vista will be easy.

He said: "Woopra, that was fast!!"

Sun, 28 Dec 2008 11:26:10 +0100

On the 24th of November of 2008, Elie came to LAU after being graduated for almost a year and a half. We all thought that he's coming for a technical presentation about his famous Woopra. But once we gathered ourselves, CSC, COE, ELE and some Graphic Design students, along with the faculty of Maths and Computer Science division and the dean of The School of Arts and Sciences, Elie began his presentation. It was amazing and fast although he covered the most important features of Woopra and how he got the idea to do it. It is never useless to attend that presentation and especially after that Elie Khoury began to chat with the audience about what they should do. He was motivating them indeed. He wanted to see all the CSC and COE students working with websites and blogs. He even offered to host for those who cannot host servers. And that is all for motivating the students to start their road to success.

If worked well, students can go very BIG just like Elie and have their own successful products maybe similar to what Woopra did.

Woopra is a web analytics service offered by iFusion Labs LLC that generates live detailed statistics about the visitors to a website. The service is provided in real-time using a desktop application. Woopra was developed by Elie Khoury and Jad Younan of Lebanon. The two met after winning a computer science national award at university. Statistics junkies frustrated with current web statistics packages, they decided to create their own stats program, breaking all the rules for current online web analytics programs. There are three parts to Woopra: Web and Desktop. Registered Woopra members can monitor their blog stats on the Woopra Member Panel on the Woopra site. Members can also track live statistics on their computers with the Woopra Desktop Client installed and linked to their website through a JavaScript. A WordPress Plugin and other blogging and web platform extensions, add-ons, and plugins are also available to bring Woopra analytics to the member's web interface such as the Woopra WordPress Plugin which allows viewing web analytics on their WordPress Administration Panel. With the upcoming release of the Woopra API, members will be able to develop a wide range of third party applications to enhance Woopra's statistics with their websites and blogs.from: http://en.wikipedia.org/wiki/WoopraLorelle, one of the very famous bloggers, says:"I’m rarely totally and completely blown away by anything, and yesterday at WordCamp Dallas, John Pozadzides blew the whole crowd away with his new blog statistics program, Woopra."John Pozadzides being the author of the popular One Man’s Blog, and an experienced web user who is now the CEO of the iFusion Labs LLC.Myo Kyaw Htun says: "I was long time back that I get a chance to use Woopra but I did not use it since I was already using Google Analytics and reinvigorate for my site. I started testing it since last week and impressed it. Woopra, a site analytics tool got good review as soon as it was released as private beta. Woopra does everything like site analytics tools do but it has additional features that you can’t find in other analytics tools."Cali Lewis, a blogger who attended the WordCamp in Dallas, said in an interview: "Web site stats might be interesting to those of us who have Web sites, but Woopra makes stats addictive and quite frankly, entertaining. It’s sticky, and if you own a Web site, you’re going to want to have it running on a screen, the same way a day trader keeps a stock ticker and CNBC running non-stop."and i agree with Cali. i have a few websites that don't even have a domain name, i'm running Woopra to do their analytics :D and got addicted already. although they have been published not more than a month.

so what Elie asked for is to be motivated and start your own little website/blog, put some adds on it and get some cash. who knows? maybe you will end up like Elie one day; someone who had a vision, got to it with his own effort and became The Entrepreneur he always wanted to be.
Cheers