Open Source Cloud Authors: Liz McMillan, Rostyslav Demush, Jason Bloomberg, Yeshim Deniz, Stackify Blog

Related Topics: Open Source Cloud

Open Source Cloud: Article

AjaxWord: An Open Source Web Word Processor

AjaxWord: An Open Source Web Word Processor

Initializing the Application User Interface and Asynchronous Communications
After all script files have been downloaded, AjaxWord initializes its user interface by loading the following HTML document (ajaxword.html). It, in turn, loads two additional HTML documents, nwWordIEMenubar.html and nwWordBg.html. The entire user interface is defined by these two HTML documents. The former defines the menu bar and toolbar. The latter defines the application's MDI environment. Listing 5 is the HTML document (ajaxword.html) responsible for initializing the application user interface

After ajaxword.html finishes loading, the "onLoad" event will cause the "initDoc" method defined in this HTML document to be executed, which in turn loads nwWordIEMenubar.html and nwWordBg.html into separate container panels.

As you might have noticed from Listing 15.5, ajaxword.html also defines a few hidden "Iframe" objects. These Iframe objects are used for asynchronously communicating with the server. XML HttpRequest is not the only way to do asynchronous communication in the AJAX model. In some cases, it's actually more convenient to use the hidden "Iframe" instead. When AjaxWord was written, "Iframe" was the only option.

Further, ajaxword.html contains a few "form" elements that all fields are hidden fields. These forms are actually used to do asynchronous communications as well. When the AjaxWord client needs to send a message to the server in the background, the message is actually inserted into a hidden form field and posted to the server side as a "multipart/form-data" URL request.

Connecting the UI to Application Logic
After the nwWordIEMenubar.html file is loaded, nwWord.js is loaded in the background (actually it was already loaded by the initial loading progress screen and then cached by the browser) and the "initWord" method is called at the "onLoad" event:

<body scroll="no" class="toolbarBody"
      onselectstart="event.cancelBubble=true;return false;"

The "initWord()" method defined in "nwWord.js" initializes the AjaxWord client logic. It instantiates the menu bar and toolbar JavaScript controllers and associates them with the actual view objects. It also instantiates a "nwWordGUIActionListener" that listens to the menu bar and toolbar events. This is done by calling the global event manager and registering this listener object with "MenuClick," "BUTTONCLICK," "FOCUS," and "BLUR" events. "initWord" also registers the "onWordExit" method to handle the browser window close event - a subject that will be explained later in this chapter.

Event Processing
"nwWordGUIActionListener.js" defines the event-handling code for this application. After it's instantiated and registered as the event handler for all menu bar and toolbar events, the event manager will route these events to this object.

This object contains two methods: onMenuClick and onButtonClick. These two methods are actually implemented by the same JavaScript function called "menuClicked." For each event, this JavaScript function will examine the "command" parameter and the source object, and route the event to the appropriate destination for processing

Handling the Application's Exit
Unlike classic Web application developers, AJAX application developers have to pay special attention to the client-side "exit" event (say the user clicks the "close" button in the browser window). The reason is that AJAX applications typically hold state information on the client side. If the browser window is closed without proper handling, the client-side state will be lost and cause problems for the application.

AjaxWord is a good example. When the user is editing a document, if he somehow clicks the "close" button on the browser window by mistake, the browser window will be closed and his document lost.

A general way to handle this situation is to register an event handler for the "onbeforeunload" event of the "window" object. The event handler can do processing before the browser window is closed.

The code below is the "onbeforeunload" event handler for AjaxWord. It loops though all the currently opened editing windows (stored in the "winArray" variable). For each visible editing window, it tries to save the content (the logic defined in the "onClose()" method for the "window" object). In the end, the event handler asks the user whether he or she really wants to exit from AjaxWord. If the user chooses "cancel" from the dialog, the event will be cancelled. If the user chooses "ok" from the confirmation dialog, the browser window will be closed and the application terminated on the client side.

The event handler code is:

function _onWordExit()
   for(var i=0;i<winArray.length;i++)
     var wi=winArray[i];
           event.returnValue="Exit from AjaxWord?";
         return false;
   if(event) event.returnValue="Exit from AjaxWord?";
   return true;

AjaxWord Server Logic
AjaxWord server code is actually fairly simple, straightforward Java code. It does user registration, verification, and loads and saves files. Such tasks are trivial to Java developers and so we're not going to elaborate on them.

AjaxWord is a Web-based word processor that aims to mimic Microsoft Word. It closely resembles the look-and-feel of Microsoft Word with a rich graphical user interface, partial screen update, and asynchronous server communications. Its Web-based nature lets users securely store user documents on the server and so gives users the flexibility to use the application from anywhere.

Writing complex applications like AjaxWord requires careful design - otherwise there will be significant development and maintenance challenges. AjaxWord uses a central controller to manage and dispatch requests on the server side. On the client side, it separates all rich UI widget-related code into a generic AJAX toolkit and uses an "event dispatching" mechanism to process client events.

AJAX applications tend to keep state information on the client side. This requires developers to pay attention to state consistency. For example, it's recommended that they write code to handle application state when the user closes the browser window.

AjaxWord is open source. It's available as a free service at www.ajaxword.com. Developers can also download the entire code from this Web site.

More Stories By Coach Wei

Coach Wei is founder and CEO of Yottaa, a web performance optimization company. He is also founder and Chairman of Nexaweb, an enterprise application modernization software company. Coding, running, magic, robot, big data, speed...are among his favorite list of things (not necessarily in that order. His coding capability is really at PowerPoint level right now). Caffeine, doing something entrepreneurial and getting out of sleeping are three reasons that he gets up in the morning and gets really excited.

Comments (2) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

Most Recent Comments
bijalvp 10/07/09 03:08:00 AM EDT

Great post. Thank you for sharing about what seems to be a great platform. Your website www.ajaxword.com is not accessible however so cannot get to the source code. Can you kindly tell me how to access this information and/or website?

Thanks again.


arun_in_1980 11/01/08 05:09:44 AM EDT

i have gone through your site http://ajax.sys-con.com/node/345840 and found that ajaxword is a very good application.
as stated that www.ajaxword.com has all the necessary information and source code for this application, this site (www.ajaxword.com) is not working.

Please look into the matter and please give me some other link or other source to get source code of this application.

Given the listings of code at http://ajax.sys-con.com/node/345840 are not appropriate as they only give the technical overview of the application.

So please provide me the full source code so that i can take advantage of it.

[email protected]

@ThingsExpo Stories
DevOpsSummit New York 2018, colocated with CloudEXPO | DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City. Digital Transformation (DX) is a major focus with the introduction of DXWorldEXPO within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of bus...
Cloud Expo | DXWorld Expo have announced the conference tracks for Cloud Expo 2018. Cloud Expo will be held June 5-7, 2018, at the Javits Center in New York City, and November 6-8, 2018, at the Santa Clara Convention Center, Santa Clara, CA. Digital Transformation (DX) is a major focus with the introduction of DX Expo within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive ov...
DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
DXWorldEXPO LLC announced today that ICOHOLDER named "Media Sponsor" of Miami Blockchain Event by FinTechEXPO. ICOHOLDER give you detailed information and help the community to invest in the trusty projects. Miami Blockchain Event by FinTechEXPO has opened its Call for Papers. The two-day event will present 20 top Blockchain experts. All speaking inquiries which covers the following information can be submitted by email to [email protected] Miami Blockchain Event by FinTechEXPO also offers s...
DXWorldEXPO | CloudEXPO are the world's most influential, independent events where Cloud Computing was coined and where technology buyers and vendors meet to experience and discuss the big picture of Digital Transformation and all of the strategies, tactics, and tools they need to realize their goals. Sponsors of DXWorldEXPO | CloudEXPO benefit from unmatched branding, profile building and lead generation opportunities.
Dion Hinchcliffe is an internationally recognized digital expert, bestselling book author, frequent keynote speaker, analyst, futurist, and transformation expert based in Washington, DC. He is currently Chief Strategy Officer at the industry-leading digital strategy and online community solutions firm, 7Summits.
Digital Transformation and Disruption, Amazon Style - What You Can Learn. Chris Kocher is a co-founder of Grey Heron, a management and strategic marketing consulting firm. He has 25+ years in both strategic and hands-on operating experience helping executives and investors build revenues and shareholder value. He has consulted with over 130 companies on innovating with new business models, product strategies and monetization. Chris has held management positions at HP and Symantec in addition to ...
Cloud-enabled transformation has evolved from cost saving measure to business innovation strategy -- one that combines the cloud with cognitive capabilities to drive market disruption. Learn how you can achieve the insight and agility you need to gain a competitive advantage. Industry-acclaimed CTO and cloud expert, Shankar Kalyana presents. Only the most exceptional IBMers are appointed with the rare distinction of IBM Fellow, the highest technical honor in the company. Shankar has also receive...
Enterprises have taken advantage of IoT to achieve important revenue and cost advantages. What is less apparent is how incumbent enterprises operating at scale have, following success with IoT, built analytic, operations management and software development capabilities - ranging from autonomous vehicles to manageable robotics installations. They have embraced these capabilities as if they were Silicon Valley startups.
Poor data quality and analytics drive down business value. In fact, Gartner estimated that the average financial impact of poor data quality on organizations is $9.7 million per year. But bad data is much more than a cost center. By eroding trust in information, analytics and the business decisions based on these, it is a serious impediment to digital transformation.
Predicting the future has never been more challenging - not because of the lack of data but because of the flood of ungoverned and risk laden information. Microsoft states that 2.5 exabytes of data are created every day. Expectations and reliance on data are being pushed to the limits, as demands around hybrid options continue to grow.
The standardization of container runtimes and images has sparked the creation of an almost overwhelming number of new open source projects that build on and otherwise work with these specifications. Of course, there's Kubernetes, which orchestrates and manages collections of containers. It was one of the first and best-known examples of projects that make containers truly useful for production use. However, more recently, the container ecosystem has truly exploded. A service mesh like Istio addr...
Digital Transformation: Preparing Cloud & IoT Security for the Age of Artificial Intelligence. As automation and artificial intelligence (AI) power solution development and delivery, many businesses need to build backend cloud capabilities. Well-poised organizations, marketing smart devices with AI and BlockChain capabilities prepare to refine compliance and regulatory capabilities in 2018. Volumes of health, financial, technical and privacy data, along with tightening compliance requirements by...
As IoT continues to increase momentum, so does the associated risk. Secure Device Lifecycle Management (DLM) is ranked as one of the most important technology areas of IoT. Driving this trend is the realization that secure support for IoT devices provides companies the ability to deliver high-quality, reliable, secure offerings faster, create new revenue streams, and reduce support costs, all while building a competitive advantage in their markets. In this session, we will use customer use cases...
Business professionals no longer wonder if they'll migrate to the cloud; it's now a matter of when. The cloud environment has proved to be a major force in transitioning to an agile business model that enables quick decisions and fast implementation that solidify customer relationships. And when the cloud is combined with the power of cognitive computing, it drives innovation and transformation that achieves astounding competitive advantage.
With 10 simultaneous tracks, keynotes, general sessions and targeted breakout classes, @CloudEXPO and DXWorldEXPO are two of the most important technology events of the year. Since its launch over eight years ago, @CloudEXPO and DXWorldEXPO have presented a rock star faculty as well as showcased hundreds of sponsors and exhibitors! In this blog post, we provide 7 tips on how, as part of our world-class faculty, you can deliver one of the most popular sessions at our events. But before reading...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
The IoT Will Grow: In what might be the most obvious prediction of the decade, the IoT will continue to expand next year, with more and more devices coming online every single day. What isn’t so obvious about this prediction: where that growth will occur. The retail, healthcare, and industrial/supply chain industries will likely see the greatest growth. Forrester Research has predicted the IoT will become “the backbone” of customer value as it continues to grow. It is no surprise that retail is ...
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
DXWorldEXPO LLC announced today that "Miami Blockchain Event by FinTechEXPO" has announced that its Call for Papers is now open. The two-day event will present 20 top Blockchain experts. All speaking inquiries which covers the following information can be submitted by email to [email protected] Financial enterprises in New York City, London, Singapore, and other world financial capitals are embracing a new generation of smart, automated FinTech that eliminates many cumbersome, slow, and expe...