In this release the following remarkable changes and additions have been made:
the IoC container is now ActionScript 3 compatible
command factories for Cairngorm’s FrontController
more PureMVC experimenting
ActionScript 3 compatibility
We got lots of reactions from people who wanted to use Prana in ActionScript projects but couldn’t because Prana relied heavily on some Flex framework specific classes. Well, we have now resolved this issue by completely refactoring the IoC container and parser so that all Flex dependencies are removed. As a result we now have 2 different application context implementations. The first one is the standard XMLApplicationContext which is aimed to be ActionScript 3 compatible. The second one is the FlexXMLApplicationContext which actually extends the XMLApplicationContext and adds support for Flex specific classes like ArrayCollection. The application context and the XML parsers are now configurable with XML node parsers and reference resolvers so it would theoretically be possible now to extend the XML dialect with your own tags and have them parsed by the application context.
Command Factories for Cairngorm’s FrontController
In order to reach maximum flexibility in setting up commands and business delegates, we have introduced the option to create custom command factories that plug into Cairngorm’s FrontController. The FrontController actually allready acts as a command factory since it takes an event name, looks up its corresponding command and instantiates that command. We have abstracted that behavior so that it is now possible to write a custom implementation of a command factory and register it with the FrontController. This is very handy when you want commands to handle different implementations of business delegates without the need to instantiate a business delegate directly in a command, making it hard to test and change.
What follows is an example of a command that is configured with a business delegate at runtime via the IoC container.
[AS]public class AuthenticateUserCommand extends AbstractResponderCommand {
override public function execute(event:CairngormEvent):void {
super.execute(event);
var e:AuthenticateUserEvent = event as AuthenticateUserEvent;
IUserDelegate(businessDelegate).authenticate(e.username, e.password);
}
}[/AS]
Notice that we are registering the command factory with the FrontController via the “method-invocation” element. This is a new XML element that was introduced this release and that is actually preprocessed to a MethodInvokingFactoryObject.
Further, we are configuring the FrontController with a BusinessDelegateFactory which is available in the Prana Cairngorm extensions. We need to specify a name of the business delegate class we want the factory to create and also pass in a reference to the appropriate service. We also need to make clear to the FrontController what commands need to be created via this factory. As you can see we added 2 types of commands, a AuthenticateUserCommand and a AuthenticateSSOUserCommand.
When the FrontController receives an event, it will look up the corresponding command (just like it works in Cairngorm), but instead of creating a command via its class name on the fly, the controller will lookup the command factory it needs to use and then use that factory to create the command. In the example, a command will be created and a business delegate will be injected.
More PureMVC Experimenting
The Prana-PureMVC team has been playing around with some new ideas around better integration between the two frameworks. Some of the key changes and improvements are:
changes in internal implementation which are not so much visible from the end user standpoint, but can potentially have some impact on wider prana/puremvc acceptance
new feature which enables significant reduction of name constants during registration, retrieval and removal of puremvc elements (proxies, mediators and commands)
new feature which enables additional and different startup idiom with which prana can be initialized late instead of up front as it had to be before
For a full and in depth discussion on these changes, please see the text file at “prana-sample-anotherArch101Demo/resources/docs/pranaPureMvcIntegration-FurtherDevelopment.txt”.
Conclusion
We hope you enjoy this release and we are always interested to hear from you. So if you have any comments or suggestions, be sure to join our forum at http://prana.herrodius.com.
In this release we further focused on bringing the core Inversion of Control container API closer to that of the well known Spring API. In addition, the release also contains the following:
an XSD for editing object definition XML files
application context classes that extend the object factory
support for external property files to be used in an application context
support for multiple configuration files
updated support for PureMVC 2.0.3
updated samples
several new utility methods and enhancements to the existing ones
complete new build system and project layout
setup wizard to configure prana inside eclipse
minor bugfixes
Using the XSD
The XML Schema Definition (XSD) is a useful aid in creating object definition XML files. It has the advantage that your object definition XML files will be validated as you create them and a good XML editor will also give you code hinting on the available elements and attributes. In order to use it, make sure you are using an XML editor that has XSD support and place the following in your XML file:
Note: There is a free XML editor available for Eclipse in the Eclipse Europa release. See the Web Tools Platform for more details.
The Application Context
As of this release, we have introduced the concept of the application context. This is actually an extension class of the object factory that offers additional functionality. As a result, we recommend updating your code to use the XMLApplicationContext instead of the XMLObjectDefinitionsLoader.
What follows is an example of how to use the XMLApplicationContext. All samples in this release have been updated to also use the XMLApplicationContext.
[AS]// load a single ‘applicationContext.xml’ config
var applicationContext:XMLApplicationContext = new XMLApplicationContext(”applicationContext.xml”);
applicationContext.addEventListener(Event.COMPLETE, onApplicationContextComplete);
applicationContext.load();
// load multiple config files
var applicationContext:XMLApplicationContext = new XMLApplicationContext([”applicationContext-1.xml”, “applicationContext-2.xml”]);
applicationContext.addEventListener(Event.COMPLETE, onApplicationContextComplete);
applicationContext.load();[/AS]
Note: There is no support for the <import> tag at this moment.
External Properties
Is some scenarios it might be useful to store certain properties of the config XML file externally so that you can easily change them without having to go through the entire config. The application context now allows you to specify external properties in separate Ant like *.properties files. You can then define property placeholders in your config files with the ${…} syntax.
Here’s an example. Note that the path to the *.properties file is relative to the path of the config file.
[XML]// in a file called strings.properties
s1=First string
s2=Second string
// in the config file
[/XML]
Building Prana and Setting up your Eclipse Environment
The way the Prana source tree is structured has changed drastically. The new project layout now allows us to create separate branches of the main source tree, the samples and the additional support projects. If you plan on building the sources yourself, please see the prana-install project and the documentation (prana-install/resources/docs/installation-instructions.txt) that contains instructions on how to set it up.
Here’s the relevant part of the docs to give you a head start.
- Checkout “prana-install” project from https://prana.svn.sourceforge.net/svnroot/prana/prana-install/trunk
- Checkout other projects that you want to have in your Flex Builder workspace. You don’t have to checkout all of them, but you must keep original names (”prana-main”, “prana-main-tests” etc.) since a build system relies on them:
https://prana.svn.sourceforge.net/svnroot/prana/prana-main/trunk
https://prana.svn.sourceforge.net/svnroot/prana/prana-main-tests/trunk
https://prana.svn.sourceforge.net/svnroot/prana/prana-sample-cairngormStore/trunk
https://prana.svn.sourceforge.net/svnroot/prana/prana-sample-movieApp/trunk
https://prana.svn.sourceforge.net/svnroot/prana/prana-sample-puremvcArch101Demo/trunk
- Open main build file from “prana-install” project (prana-install/ant/build.xml) and run and “setup-projects” target.
- Answer to questions in GUI wizard.
- Wait until Flex Builder finishes building a workspace.
- That’s it. Your workspace should now be fully configured.
To check if everything is set up correctly, you can try some of targets from each project’s main build file located in “[project-name]/ant/build.xml”.
For example:
- prana-main/ant/build.xml -> “release” target
- this target creates release archives in “prana-main/antbuild/release”
- prana-main-tests/ant/build.xml -> “tests-run” target
- this target runs tests and creates HTML report in “prana-main-tests/antbuild/reports/tests/html”
- prana-sample-[sample-name]/ant/build.xml -> “run-defaultApp” target
- this target runs the sample in a configured browser
If you don’t want to checkout the sources from SVN, you can download the prana-projects-0.5.zip file that contains all projects. It is then possible to import those projects in your Eclipse environment. Please see the readme file that comes with the prana-projects-0.5 distribution for more info.
Conclusion
We hope this release will prove valuable to all Flex developers out there. Whether you’re just using Prana’s utilities, the Cairngorm or PureMVC extensions or the full blown IoC container, there definitely will be something helpful for you.
Don’t hesitate to get in touch with the development team and other Prana users via our mailinglist. We appreciate all feedback, be it questions, comments, new ideas or code contributions.
