Latest News from Anil Sharma

AJAX Book Preview: "Controller"

Wed, 16 May 2007 19:30:00 EDT

In the previous section we discussed a set of abstractions that are sub-classes of the component. A component class abstracts some behavior and to implement that, it might add a set of event listeners to its elements. Those event handlers are encapsulated in the component class and serves as its controllers. But in a bigger scheme of things, they are fully contained in the component class and can be considered a part of the View.

The Web Page as an Application

Wed, 16 May 2007 19:15:00 EDT

AJAX is the right technology for a Web-enabled rich user interface (UI). But as with any technology, unstructured software created using it is a recipe for failure. AJAX is a set of powerful and flexible technologies but its disorderly use can result in spaghetti code. If the code isn't structurally sound, the interface it presents to users is unfriendly and non-intuitive, whereas a structurally sound and cohesive system flows smoothly and delights its user.

Real-World AJAX Book Preview: Post Changes to the Servlet

Wed, 18 Apr 2007 08:00:00 EDT

In the MainPage-9.html, we add a new link called 'Save' in the top toolbar. It's used to save the changes made by the user using an AJAX request.

Real-World AJAX Book Preview: Row Selection in the SimpleTable

Tue, 17 Apr 2007 08:00:00 EDT

Note in the 'setData' method of the SimpleTable, the following code. The code to add 'cellClicked' as an 'onclick' listener to each cell. The ID attribute of each attribute is set so that we can parse it to retrieve the row and column of the cell.

Real-World AJAX Book Preview: XMLToDataSet Class

Mon, 16 Apr 2007 08:00:00 EDT

In the previous sections, we've discussed the HTML template and a component class called 'NavBar.' Next we'll discuss more templates and the component classes that are bound to the application data. But before that, we'll discuss how the data is converted to the internal form. The XML document received by the client is converted to the JavaScript object tree. The XMLToDataSet class is responsible for the conversion.

Real-World AJAX Book Preview: Navigation Bar as a Template

Sun, 15 Apr 2007 08:00:00 EDT

Refer to TopNavBar.html. This is a pure HTML document. It's created to act as a template for the navigation bar. Note the 'id' assigned to each anchor element. The screenshot of the navigation bar template is shown below.

Real-World AJAX Book Preview: Source Code Organization - Directory Structure

Sat, 14 Apr 2007 08:00:00 EDT

Let's look at the source code organization in our sample application. It's important from two perspectives: a) it would be useful in browsing the sample code described in the following sections; and b) the directory structure helps visualize the structure of the pages. We use the directory structure below for source code organization.

Real-World AJAX Book Preview: An AJAX UI Versus Server-Side Presentation

Fri, 13 Apr 2007 08:00:00 EDT

JSP, JSF, special tags, configuration files, and tld files are all replaced by client-side HTML templates, components, and controllers. We only need a controller servlet on the server side.

Real-World AJAX Book Preview: Change Set for Server-Client Interaction

Wed, 11 Apr 2007 08:00:00 EDT

When the user makes changes to the data, all the changes can be recorded locally up to some point or sent to the server immediately. It depends on the application situation. In a typical application, there are certain changes that are buffered until the user selects an operation to indicate 'save.'

Real-World AJAX Book Preview: Server Side - Controller Servlet

Tue, 10 Apr 2007 08:00:00 EDT

The controller servlet orchestrates interaction between the client- and server-side components that serve as the real data sources or service providers. The client uses XML messages to send details of server invocations. The controller servlet interprets the XML messages and delegates calls to actual services. It might have to transform these XML messages to different protocols based on what's supported by each service.