In this article I would like to give you a tutorial in order to invoke SAP web services with Flex using Cairngorm framework. Cairngorm is one of the primary MVC open source frameworks for application architecture in Adobe Flex. Objects in the view are bounded with view locator application objects and throws events such as Clicked , Dragged , Dropped and so on. Command: Manage the business logic of your application.
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Each view is defined in its own mxml file in the "uk. Notice how the selectedIndex property of the ViewStack is bound to the.
This means that the currently selected view may be changed by changing the model. So now let's drill down into the InitialView component. We can then see the details of what is presented to the user, and what happens when the user responds to that interface. InitialView is itself an mxml component based upon the standard VBox component. It contains some script and some UI components. Firstly, the script contains a bindable reference to the AppModelLocator singleton.
Below this text component there is a button "translate". Clicking this button calls an actionscript method in the script on the page. The method is called translate. It could at that point do some validation, or request further input. However, in this case all that we want it to do is fire of a request for the text "Hello everyone" to be translated.
The least impressive Flex app ever. The DataChangeEvent is defined in the "uk. It is a cairngorm event extended to carry our message. We can create events that can carry whatever data we need to be passed to a command. For example, a user types their username and password into a login box, this is then wrapped in a LoginEvent, and the event dispatched. A LoginCommand receieves the event and attempts a login using a LoginDelegate and login service. If succesful, the command changes the current view to one appropriate to a signed in user.
The next step is to dispatch that event and its message to the Cairngorm controller. This should then get passed on to the required "command" object the command object contains the code for executing the requested command.
But how does the controller know which command object to use? Events are mapped on to commands in the control. This is where we do the work that results in the translation.
In this simple example, the. However, we could instead refer to an English-Steswana dictionary to retrieve the translation. This might even require the use of an external data service. The DataChangeCommand would then delegate the work of sending this external request to a Delegate class in the "business" folder. The delegate, on retrieving the required translation, calls back to the DataChangeCommand to complete the requried command, or alternatively calls a seperate command.
So, with the text control on the current view bound to the. But what if we also need to change the current view, for example to the AlternativeView control in the ViewStack? The command simply alters the. As the selectedIndex property of the ViewStack is bound to.
Look - it speaks Setswana! Transversality - Robert O'Toole. The app doesn't do much, initially displaying "hello everyone", along with a button that translates that message, and a second button that changes the background colour of the component. Exciting stuff! But the Cairngorm framework is. Download the source code for my demo application. Read the full article Explanation Here is a screenshot of the Navigator window for the project: The Cairngorm source code is included in the "com" folder although it could be compiled and included as an external library.
The "uk. This has six subfolders, each containing classes responsible for different parts of the MVC architecture: view, control, command, business actually meaning data and comms services , model, vo value object. As with all Flex applications, there is a single container mxml file, called Main. I'll start my explanation of this app and Cairngorm with this top-level container.
The Main. Conclusion This may be a simple example, but I can already see how using the Cairngorm framework will simplify the task of building very complex applications, resulting in better, more rational and sustainable code. No comments. Add a comment You are not allowed to comment on this entry as it has restricted commenting permissions. Search this blog.
Getting Started With Cairngorm 3
Each view is defined in its own mxml file in the "uk. Notice how the selectedIndex property of the ViewStack is bound to the. This means that the currently selected view may be changed by changing the model. So now let's drill down into the InitialView component. We can then see the details of what is presented to the user, and what happens when the user responds to that interface. InitialView is itself an mxml component based upon the standard VBox component.
List of Flex frameworks
Over the past few years, Cairngorm architecture has been hugely embraced for developing enterprise Flex applications. While there are a lot of sources available online that demonstrate building flex applications using Cairngorm Architecture, not many serve the cause if you intend to develop Modular Flex Applications using Cairngorm Architecture. Brief description of Flex Modules: Flex Modules are code functionality compiled to dynamically-loadable SWF files that can be loaded and unloaded by an application at run-time. Modules let you split your application into several pieces, or modules.
Agile Enterprise Application Development with Flex by Tony Hillerson
A collaboration of recognized design patterns, Cairngorm exemplifies and encourages best-practices for RIA development advocated by Adobe Consulting, encourages best-practice leverage of the underlying Flex framework, while making it easier for medium to large teams of software engineers deliver medium to large scale, mission-critical Rich Internet Applications. Cairngorm follows the principle of separating the view and business logic which is known as the Model-View-Controller pattern MVC. The following list shows the different elements that form the framework. View : Contains UI controls for user interaction and displays the state of the models data.
Cairngorm Framework for Flex Developers
The architectural framework Cairngorm was created by Alistair McLeod and Steven Webster while they were working at the company iteration::two they are presently employed by Adobe Consulting. It was open sourced in the summer of Cairngorm was designed to ensure that UI components do not need to know where data is located. The business layer retrieves data from the servers and stores it in the memory objects that represent the data model, which use binding to notify the UI components about data arrival or changes.